6. Conceptual Design

Transmission Project Preparatory Survey Phase III

Final Report (Advanced Release)

6-1

6. Conceptual Design

6.1. Overhead Transmission Line Design Concept The design concept, including the following criteria focused on cost reduction, will be implemented

based on the information collected and organized. The details of each criterion will be discussed with

the counterpart organization based on the results of the field survey. For the 500kV Pharyargyii ~ Sar

Ta Lin transmission line, in order to systematically connect the Pharyargyii ~ Hlaingthaya transmission

line to the Pharyargyii Substation in the future, the same equipment specifications were implemented

considering system reliability and O&M for the 500kV transmission system. The 230kV transmission

line will also be matched with the existing transmission line in Yangon city, so that the equipment

specifications will not conflict, for reasons of system reliability and O&M. In addition, if the

transmission line is heavily loaded with current flow, the application of low-loss conductor technology

will be considered.

Normal ACSR Conductor Low-loss Conductor

Figure 6.1-1 Normal ACSR Conductor and Low-loss Conductor

6.2. 500kV Transmission Line Design

Overview of Transmission Line Route The route connecting Pharyargyii Substation and Sar Ta Lin Substation has an approximate route

distance of 70km. Most of the route is along the river side.

Figure 6.2-1 Route of 500kV Pharyargyii S/S – Sar Ta Lin S/S

Design Conditions The basic design conditions are as mentioned below.

Pharyargyii－Sar Ta Lin 500kV T/L

Route

Pharyargyii S/S

Sar Ta Lin

S/S



6-2

(1) Ambient Temperature Maximum air temperature 46 ºC

Minimum air temperature 10 ºC

Annual average temperature 27 ºC

(2) Conductor Temperature Maximum temperature 75 ºC

Minimum temperature 10 ºC

(3) Wind Velocity Maximum wind velocity 35 m/s

(4) Wind Pressure Tower 2,150 Pa

Conductor 900 Pa

Ground wire 970 Pa

Insulator 900 Pa

(5) Stringent (the most severe design) Conditions and EDS (Every Day Stress) Conditions

Conductors: Condition Temperature Wind Tension

Stringent 15 ºC 900 Pa 40.0% UTS

EDS 27 ºC Still air 22.2% UTS

Ground Wires: Condition Temperature Wind Tension



*UTS: Ultimate Tension Strength

(6) Pollution Level Medium (IEC standard); 34.7 mm/kV

(7) Other conditions assumed Maximum humidity 100%

(8) Voltage Level for Insulation Design Lightning Impulse Withstand Voltage 1, 550 kV

Switching Impulse Withstand Voltage 1,175 kV

Maximum System Voltage 550 kV

(9) Air Clearance Normal condition (D1) 4,700 mm

Normal wind condition (D2) 4,200 mm (swing angle: 15º - 20º)

Maximum wind condition (D3) 1,900 mm (max. swing angle: 60º)

(10) Safety Factors Required minimum safety factors for the transmission line facilities were determined as

follows.

(a) Towers

1.6 to yield strength of the material under normal conditions (= stringent conditions)

1.3 to yield strength of the material under broken-wire conditions (= normal conditions +

one ground wire or one phase conductor breakage)

(b) Conductor/Ground wire

2.5 to UTS (Ultimate Tensile Strength) for stringent conditions

4.5 to UTS for Everyday Stress (EDS) condition at average temperature in still air at

supporting point

(c) Insulator string

2.5 to RUS (Rated Ultimate Strength) for maximum working tension at supporting point

(d) Foundation

2.0 under normal conditions



6-3

1.5 under broken wire conditions

Conductor and Ground Wire Design

(1) Conductor and ground wire The results from power flow system analysis showed that 4 bundles of ACSR 468 mm2 (Drake) for

conductors are appropriate for the project. Therefore, ACSR 468 mm2 for conductor and OPGW 115

mm2 and AS 110 mm2 for ground wire are applied. The technical characteristics of the conductor and

ground wires are shown in the following tables.

Table 6.2-1 Technical Characteristics of Conductor Type ACSR 468 ASTM (Drake)

Component of stranded wire (Nos./Dia.) Al: 26/4.442 mm

St: 7/3.454 mm

Overall Diameter 28.13 mm

Cross Sectional Area of Aluminum wires 402.8 mm2

Cross Sectional Area (Total) 468.6 mm2

Nominal Weight 1,628 kg/km

Ultimate Tensile Strength 140.2 kN

Modulus of Elasticity 76.0 GPa

Co-efficient of linear expansion 19.1 x 10-6/℃

DC Resistance at 20℃ 0.07167 Ω/km

Table 6.2-2 Technical Characteristics of Ground Wires Type OPGW115 mm2 AC110 mm2

Component of stranded wire (Nos./Dia.)

AA: 12/2.85 mm

AS: 19/2.85 mm

SUS: 1/2.80 mm

20SA: 19/2.7 mm

Overall Diameter 14.25 mm 13.5 mm

Cross Sectional Area (Total) 114.83 mm2 108.8 mm2

Nominal Weight 483 kg/km 722.5 kg/km

Ultimate Tensile Strength 72.4 kN 145.8 kN

Modulus of Elasticity 97.7 GPa 155.2 GPa

Co-efficient of linear expansion 17.5 x 10-6/℃ 12.6 x 10-6/℃


(including OP unit) 0.787 Ω/km

Number of Optical Fibers 24 –

(2) Maximum Tension and Every Day Stress (EDS) The standard span length was assumed as 450 m. The values of the maximum working tension and

the EDS of both the conductor and the ground wires satisfy the determined safety factors shown in the

following table.

Table 6.2-3 Maximum Working Tension and Every Day Stress Type UTS Tension Safety Factors

ACSR 468 mm2

(Drake) 140.2 kN

Maximum Tension 53.2 kN 2.63 > 2.5

Every Day Stress 31.0 kN 4.52 > 4.5

OPGW115 mm2 72.4 kN Maximum Tension 26.5 kN 2.73 > 2.5


AC110 mm2 145.8 kN Maximum Tension 32.0 kN 4.55 > 2.5


(3) Sag and tensions of the ground wires The sags of the ground wires under EDS conditions must be below 80% of the conductors’ sag at

the standard span length to avoid a reverse flashover from the ground wires to the conductors and

direct lightning stroke to the conductors. The tensions of the ground wires are determined to satisfy

the safe separation of conductors and ground wires in the mid-span.

(4) Standard Span Length The standard span length between towers is 450 m



6-4

(5) Right of Way (ROW) The right of way of the 500kV transmission line is assumed to be 60.96m

Insulator Design

(1) Insulator type and size The insulator unit applied to the transmission line is a standard disc type porcelain insulator with

ball and socket, complying with IEC 60305. 210kN type insulators are applied for the suspension

towers and 300kN type insulators are applied for the tension towers. The technical characteristics of

the insulators are shown in the following table

Table 6.2-4 Technical Characteristics of the Insulator Rated Ultimate Strength 210 kN 300 kN

IEC Designation U210B U300B

Shell Diameter 280 mm 320 mm

Unit Spacing 170 mm 195 mm

Nominal Creepage Distance 405 mm 505 mm

Ball & Socket Coupling 20 mm 24 mm

(2) Number of insulator units per string The number of insulator units per string is 30 units for the suspension towers and 26 units for the

tension towers.

(3) Determination of Number of Insulator Strings per set The determinations of the number of insulators per string are as shown below.

Contamination design

Contamination level: Medium

Creepage distance per voltage: 34.7 mm/kV

Highest Voltage, Um:

500 kV × 1.2/1.1 ≒ 550 kV

Total Insulator Creepage Distance:

550 kV ÷ √3 × 34.7 mm/kV ≒ 11,100 mm

Number of insulator units:

U210B: 11,100 mm ÷ 405 mm = 27.41 ≒ 28 units/string


Lightning Impulse Withstand Voltage

Taking highest voltage, Um = 550 kV

Horn gab distance is 4,200 mm as specified by DPTSC in MYP8 project. However, referring to

IEC60071-1-2006, standard rated lightning impulse withstand voltage at 550 kV is 1,550 kV

and minimum horn gap distance is 3,100 mm. The ratio of horn gap distance to length of

insulator string length (Z/Zo) is decided as 85% from standard practices across the world.


U210B: 4,200 mm ÷ 0.85 ÷ 170 mm = 29.06 ≒ 30 units/string


Switching Impulse Withstand Voltage (SIWV)

Given, Surge multiplier: 2.0; Insulation deterioration coefficient: 1.1; Withstand voltage

coefficient: 1/0.85

50% Switching Surge Flashover Voltage, V50:

V50 = Um × √2 ÷√3 × 2.0 × 1.1 × 1/0.85 = 1162.3 kV

Horn gap distance without flashover in V50:

V50 = k × 1080 × ln(0.46d+1); where k: gap factor = 1.32

d = 2.74 m


U210B: 2,740mm ÷ 0.85 ÷ 170 mm = 18.96 ≒ 19 units/string

U300B: 2,740mm ÷ 0.85 ÷ 195 mm = 16.53 ≒ 17 units/string



6-5

Table 6.2-5 Determination of Number of Insulators per Strings

Type of

Insulator

Contamination

Level

Number of Insulators by

Contamination

Design

Lightningt

Impulse

Withstand

Voltage

Switching

Impulse

Withstand

Voltage

Result

U210B Medium 28 30 19 30

U300B Medium 22 26 17 26

(4) Mechanical Strength of Tension Insulator For the suspension towers, the number of insulator strings per set is either single or double 210kN

insulators, which was determined in accordance with the transmission line crossing places. For the

tension towers, the number of insulator strings per set is double the 300kN insulator. The tension

insulators must satisfy the safety factor at RUS for maximum working tension at the standard span of

450 m, as follows.

Table 6.2-6 Tension Insulator Assembly

Conductor Maximum Tension

(Span length: 450m) Insulator Tension Safety Factor

ACSR 468 mm2

"Drake'' 212.8kN (53.2kN × 4)

Double strings 600kN

(300kN × 2) 2.81 > 2.5

(5) Tension Insulator Assembly Insulator assembly fittings also have to maintain the same strength as the insulators.

Table 6.2-7 Tension Insulator Assembly

Conductor Maximum Tension


ACSR 468 mm2

"Drake'' 212.8kN (53.2kN × 4)

Double strings 600kN

(300kN × 2) 2.81 > 2.5

(6) Ground Clearance The most severe state for the ground clearance of the conductors will occur when the conductor’s

temperature rises to 75 ºC under still air conditions. The minimum height of the conductor above

ground at the 500 kV level is determined as per the below.

Table 6.2-8 Minimum Height of the Conductor above Ground Classification Applied areas for the project Clearance

Areas where people rarely enter, such as

mountains, forests, waste fields, etc.

Bush lands, forests, grass land and narrow

rivers 11.0 m

Area where people enter or will enter

frequently

Paddy fields with mosaic of croplands,

general roads and wide rivers 14.0 m

River crossing 20.0 m

Determination of Tower Configuration

(1) Electrical Clearance

Table 6.2-9 Swing Angle and Insulation Clearance

Normal Middle Abnormal

Wind velocity 0 to 10 m/s 10 to 20 m/s 20 to 35 m/s

Swing angle of suspension strings (Type DA) 0 to 15 deg 15 to 20 deg 20 to 60 deg

Swing angle of tension strings without

jumper loop (Type DB) 0 to 15 deg 15 to 20 deg 20 to 60 deg

Swing angle of tension strings with jumper

loop (Type DC, DD, DE) 0 to 15 deg N/A N/A

Clearance 4,700 mm 4,200 mm 1,900 mm

(2) Length of String Set and Drop of Jumper Loop Length of the suspension string set and drop of jumper loop are estimated as follows.



6-6

Table 6.2-10 Length of Suspension String Set and Drop of Jumper Loop Type Determination Length

Length of suspension string set

for U210B

170 mm × 30 units＋1,535 mm (fitting length) + 65 mm

(margin) 6,700 mm

Length of tension string set for

U300B

195 mm × 26 units＋2,050 mm (fitting length) + 80 mm

(margin) 7,200 mm

Drop of jumper loop for tension

string set

4,700 mm (normal insulation distance) × 1.2＋200 mm

(half of length between conductors) + 60 mm (margin) 5,900 mm

Length of support insulator

string set for DC, DD

170 mm × 30 units + 1,250 mm (fitting length) + 50 mm

(margin) 6,400 mm

(3) Clearance Diagram Clearance diagrams of suspension insulator string and drop of jumper loop are shown as follows.

Suspension Tension

Type DA Type DB Type DC, DD, DE

Figure 6.2-2 Clearance Diagram

(4) Clearance to Ground and Obstacles Clearances above ground and to each obstacle are determined as follows, including some errors

which might happen in drawings, survey, and construction.

Table 6.2-11 Clearances to Ground and Obstacles Object Conditions Clearance

Ground (Mountains or forest area)

At maximum conductor

temperature of 75 ºC

11.0 m

Ground (Paddy field) 14.0 m

River crossing (Above highest water level) 20.0 m

Road 15.0 m

Railway 16.0 m

Trees (Rubber plants, etc.) 7.0 m

Distribution line (including pole) 8.0 m

Transmission line (including tower) –

66 kV transmission line 9.0 m



Other 7.0 m

Towers

(1) Type of Towers (a) Type DA

Suspension type tower on a straight section of the line or on a section of the line with a

horizontal deviation angle up to 3 degrees with suspension insulator sets.

(b) Type DB

Tension type tower on a section of the line with a horizontal deviation angle up to 20

degrees with tension insulator sets.

(c) Type DC

Tension type tower on a section of the line with a horizontal deviation angle from 20

degrees to 40 degrees with tension and jumper suspension insulator sets.



6-7

(d) Type DD

Tension type tower on a section of the line with a horizontal deviation angle from 40

degrees up to 60 degrees with tension and jumper suspension insulator sets.

(e) Type DE

Tension type tower used at the terminal of the line with tension insulator sets having

jumper insulator sets where required with a horizontal angle up to 40 degrees.

Table 6.2-12 Tower Types and the Applied Conditions Type Position of Use Angle of Deviation [deg.] String Type

DA Straight line 0 – 3 Suspension

DB Angle 4 – 20 Tension

DC Angle 21 – 40 Tension

DD Angle 41 – 60 Tension

DE Terminal 0 – 40 Tension

(2) Design Span The design of all towers will provide for the following wind spans and weight spans.

Table 6.2-13 Design Span Tower Type Wind Span [m] Weight Span [m]

DA 450 700

DB 450 700

DC 450 700

DD 450 700

DE 450 350

(3) Maximum Sag Calculation and Standard Height of Towers Conductor temperature: 75 deg.

Wind pressure: still air

Table 6.2-14 Maximum Sag and Standard Height of Towers Suspension type Tension type

Maximum conductor sag 15.3 m 15.3 m

Insulator length 6.7 m -

Ground Clearance 14.0 m 14.0 m

Standard height of tower above

ground

(below bottom cross arm)

36.0 m 29.5 m



6-8

(4) Shape of Tower

Figure 6.2-3 Type DA Tower Figure 6.2-4 Type DB Tower

Figure 6.2-5 Type DC Tower Figure 6.2-6 Type DD Tower



6-9

Figure 6.2-7 Type DE Tower

(5) Unit Weight of Towers The unit weights of types of towers for different extension lengths are shown below.

Table 6.2-15 Unit Weight of the Towers (Estimated)

Tower extension [m] Unit weight of towers [ton]

DA DB DC DD DE

0 42.9 48.3 60.0 64.1 70.0

+3 46.7 50.9 65.7 67.1 –

Tower Foundations

(1) Tower load condition The foundation loads that are transmitted from each tower at ±0.0 m extension

Table 6.2-16 Tower Load Conditions ( 2 cct 500 kV）

Quantities of the Transmission Line Materials

(1) Number of Towers and Total Weight of Towers The assumed tower types, number of towers and the tower weight for the transmission lines are

summarized in the following table.

Table 6.2-17 Numbers of Towers and Tower Weight

Tower type Extension

[m]

Unit weight

[ton]

No. of towers

[unit]

Total weight

[ton]

Tower type Compressive load

[kN]

Tensile load

[kN]

DA 1393.6 1090.2

DB 1909.5 1573.7

DC 2671.2 2266.6

DD 3228.4 2803.6

DE 2554.0 2031.4



6-10

DA: Suspension

(Horizontal angle: 0 – 3 deg.)

0.0 42.9 117 5019.3

+3.0 46.7 5 233.5

Subtotal 122 5252.8

DB: Tension


0.0 48.3 4 193.2

+3.0 50.9 2 101.8

Subtotal 6 295.0

DC: Tension


0.0 60.0 9 540.0

+3.0 65.7 4 262.8

Subtotal 13 802.8

DD: Tension


0.0 64.1 6 384.6

+3.0 67.1 3 201.3

Subtotal 9 585.9

DE: Dead-end

(Horizontal angle: 0 – 40 deg.) 0.0 70.0 2 140.0

Subtotal 2 140.0

Total 152 7076.5

(2) Quantities of Conductors and Ground Wire The quantities of conductors and ground wires for the transmission line are computed by

multiplying the numbers of conductors or ground wires by the route length, and multiplying that

number by 1.05 for the sag allowance and margin for stringing work.

Table 6.2-18 Quantities of Conductors and Ground Wire

Conductor/Ground wire type No. of

bundles

No. of

phases

No. of

circuits

Route length

[km]

Line length

[km]

LL-ACSR 728 mm2 4 3 2 70.0 1764.0

OPGW115 mm2 1 – 1 70.0 73.5

AC110 mm2 1 – 1 70.0 73.5

(3) Quantities of Insulators and Insulator Assemblies The quantities of insulators and insulator assemblies for the transmission line are computed from

the number of suspension and tension towers, considering the number of strings.

Table 6.2-19 Quantities of Insulators and Insulator Assemblies

Insulator

type Tower type

Assembly

type

No. of

insulators

per set [pcs]

No. of

strings per

tower [set]

No. of

towers

[unit]

Subtotal

of strings

[set]

Subtotal of

insulators

[pcs]

U210B Suspension

Double 54 6 5 30 1620

Single 26 6 117 702 18252

Jumper support Single 26 6 22 132 3432

Total number for U210B 864 23304

U300B Tension Double 60 12 28 336 20160

Dead-end Double 60 12 2 24 1440

Total number for U300B 360 21600

(4) Quantities of Foundation Concretes Quantities of reinforced concrete of the foundations for 5 types of 500kV towers based on dfferent

geological type are summarized in the following table.

Table 6.2-20 Quantities of Foundation Concretes Type of

foundation Tower type Geological type

Unit concrete

[m3]

No. of tower

[unit]

Total concrete

[m3]

Pile

DA Standard 44.0 73 3212.0

Flood area 42.8 31 1326.8

DB Standard 45.6 2 91.2

Flood area 43.6 1 43.6

DC Standard 59.2 7 414.4

Flood area 63.6 4 254.4

DD Standard 96.8 4 387.2



6-11

Flood area 108.4 2 216.8

DE Standard 53.6 1 53.6

Subtotal 125 6000.0

Pad

DA – 86.6 18 1558.8

DB – 131.1 3 393.3

DC – 179.0 2 358.0

DD – 219.1 3 657.3

DE – 163.8 1 163.8

Subtotal 27 3131.2

TOTAL 152 9131.2

6.3. 230kV Transmission Line Design

Overview of Transmission Line Route The 230kV transmission line routes are described below and shown in Figure 6.3-1 and Figure 6.3-2.

The route connecting Sar Ta Lin Substation to Hlawga Substation has an approximate route

length of 17km. The overhead transmission line branches into underground line 5km before

Hlawga Substation due to there being a populated residential area around Hlawga Substation.

The towers used in this route are 4 circuit transmission towers.

The route connecting Sar Ta Lin Substation to East Dagon Substation has an approximate

route length of 19km. The towers used in this route are 2 circuit transmission towers.

Figure 6.3-1 230kV Sar Ta Lin S/S – Hlawga S/S and Sar Ta Lin S/S – East Dagon Transmission Line Route Map

The route connecting Hlawga Substation to East Dagon Substation has an approximate route

length of 22km. The overhead transmission line branches into underground line 5km before

Hlawga Substation due to there being a populated residential area around Hlawga Substation.

The new 2 circuit transmission towers will be constructed in the same position as the existing

one circuit transmission towers.

Sar Ta Lin－Hlawga 230kV T/L Route

Sar Ta Lin－East Dagon 230kV T/L Route

Sar Ta Lin

S/S

Hlawga S/S

East Dagon S/S



6-12

Figure 6.3-2 230kV Hlawga S/S – East Dagon S/S Transmission Line Route Map

Design Conditions The basic design conditions are as mentioned below.

(1) Ambient Temperature

Maximum air temperature 46 ºC

Minimum air temperature 10 ºC

Annual average temperature 27 ºC

(2) Conductor Temperature

Maximum temperature 75 ºC

Minimum temperature 10 ºC

(3) Wind Velocity Maximum wind velocity 35 m/s

(4) Wind Pressure Tower 2,150 Pa

Conductor 900 Pa

Ground wire 970 Pa

Insulator 900 Pa

(5) Stringent (the most severe design) Conditions and EDS (Every Day Stress) Conditions

Conductors: Condition Temperature Wind Tension



Ground Wires: Condition Temperature Wind Tension



*UTS: Ultimate Tension Strength

(6) Pollution Level Heavy (IEC standard); 43.3 mm/kV

(7) Other Conditions Assumed Maximum humidity 100%

Hlawga－Thaketa 230kV T/L Route

Hlawga S/S

Thaketa S/S



6-13

(8) Voltage Level for Insulation Design Lightning Impulse Withstand Voltage 1, 050 kV

Switching Impulse Withstand Voltage 460 kV

Maximum System Voltage 245 kV

(9) Air Clearance Normal condition (D1) 2,480 mm

Normal wind condition (D2) 1,760 mm (swing angle: 10º - 30º)

Maximum wind condition (D3) 550 mm (max. swing angle: 60º)

(10) Safety Factors Required minimum safety factors for the facilities of the transmission line were determined as

follows.

(a) Tower

1.6 to yield strength of the material under normal conditions (= stringent conditions)

1.3 to yield strength of the material under broken-wire conditions (= normal conditions +

one ground wire or one phase conductor breakage)

(b) Conductor/Ground wire

2.5 to UTS (Ultimate Tensile Strength) for stringent conditions

4.5 to UTS for Everyday Stress (EDS) conditions at average temperature in still air at

supporting point

(c) Insulator string

2.5 to RUS (Rated Ultimate Strength) for maximum working tension at supporting point

(d) Foundation

2.0 under normal conditions

1.5 under broken wire conditions

Conductor and Ground Wire Design

(1) Conductor and ground wire The results of the power flow system analysis showed that 2 bundles of ACSR 1272MCM 644 mm2

(Pheasant) conductor are appropriate for the project. However, since a large amount of current is

expected to flow in the three 230kV T/L in the future, the LL-ACSR 782mm2 conductors, which have

13% lower loss in conductivity and the same weight and outer shape as Pheasant, is applied. Therefore,

LL-ACSR 782mm2 for conductors, and OPGW 115 mm2 and AS 110 mm2 for ground wire, are applied.

The technical characteristics of the conductors and ground wires are shown in the following tables.



6-14

Table 6.3-1 Technical Characteristics of Conductors

Type

ACSR 1272

MCM

(Pheasant)

LL-ACSR/AS

728 mm2

Component of stranded wire (Nos./Dia.) Al: 54/3.899 mm

St: 19/2.339 mm

16/TW*1 – AL

12/TW – AL

8/TW – AL

7/3.25 –

14EAS*2


Cross Sectional Area of Aluminum wires 644.5 mm2 727.5mm2

Cross Sectional Area (Total) 726.4 mm2 785.6 mm

Nominal Weight 2,434 kg/km 2,434 kg/km




DC Resistance at 20℃ 0.04501 Ω/km 0.0392 Ω/km

Cross Sectional View

*1 TW: Trapezoid shaped wire

*2 14EAS: Extra high strength aluminum clad steel with 14% IACS conductivity

Table 6.3-2 Technical Characteristics of Ground Wires Type OPGW115 mm2 AC110 mm2

Component of stranded wire (Nos./Dia.)

AA: 12/2.85mm

AS: 19/2.85 mm

SUS: 1/2.80 mm

20SA: 19/2.7 mm


Cross Sectional Area (Total) 114.83 mm2 108.8 mm2

Nominal Weight 483 kg/km 722.5 kg/km





(including OP unit) 0.787 Ω/km

Number of Optical Fibers 24 –

(2) Maximum Tension and Every Day Stress (EDS) The standard span length was assumed as 400 m. The values of the maximum working tension and

the EDS of both the conductors and the ground wires satisfy the determined safety factors shown in

the following table.

Table 6.3-3 Maximum Working Tension and Every Day Stress Type UTS Tension Safety Factors

LL-ACSR 728 mm2 194.1 kN Maximum Tension 66.0 kN 2.94 > 2.5


OPGW115 mm2 72.4 kN Maximum Tension 24.5 kN 2.95 > 2.5


AC110 mm2 145.8 kN Maximum Tension 30.0 kN 4.86 > 2.5


(3) Sag and tensions of the Ground Wires The sags of the ground wires under EDS conditions must be below 80% of the conductors’ sag at

the standard span length to avoid a reverse flashover from the ground wires to the conductors and

direct lightning stroke to the conductors. The tensions of the ground wires are determined to satisfy



6-15

the safe separation of conductors and ground wires in the mid-span.

(4) Standard Span Length The standard span length between towers is 400 m.

(5) Right of Way (ROW) The right of way for the 230kV transmission line is assumed to be 45.72m.

Insulator Design

(1) Insulator type and Size The insulator unit applied to the transmission line is a standard disc type porcelain insulator with

ball and socket, complying with IEC 60305. 210kN type insulators are applied for the suspension

towers and the tension towers. The technical characteristics of the insulators are shown in the following

table.

Table 6.3-4 Technical Characteristics of the Insulators Rated Ultimate Strength 210kN

IEC Designation U210B

Shell Diameter 280 mm

Unit Spacing 170 mm

Nominal Creepage Distance 405 mm

Ball & Socket Coupling 20 mm

(2) Number of insulator Units per String The number of insulator units per string is 17 units for the suspension towers and 15 units for the

tension towers.

(3) Determination of number of Insulator Strings per Set The determinations of the number of insulators per string are as shown below.

Contamination design

Contamination level: Heavy

Creepage distance per voltage: 43.3 mm/kV

Highest Voltage, Um:

230 kV × 1.15/1.1 ≒ 241 kV

Total Insulator Creepage Distance:

241 kV ÷ √3 × 43.3 mm/kV ≒ 6,025 mm



Light Impulse Withstand Voltage

Taking highest voltage, Um = 241 kV ≒ 245 kV

Referring to IEC60071-1-2006, standard rated lightning impulse withstand voltage at 245 kV

is 1,050 kV and minimum horn gap distance is 2,100 mm. The ratio of horn gap distance to

length of insulator string length (Z/Zo) is decided as 75% from normal practice in the world.



Switching Impulse Withstand Voltage (SIWV) Given, Surge multiplier: 3.3; Insulation deterioration coefficient: 1.1; Withstand voltage

coefficient: 1/0.9

50% Switching Surge Flashover Voltage, V50:

V50 = Um × √2 ÷√3 × 3.3 × 1.1 × 1/0.9 = 793.6 kV

Horn gap distance without flashover in V50:

V50 = k × 1080 × ln(0.46d+1); where k: gap factor = 1.24

d = 1.76 m




6-16


Table 6.3-5 Determination of Number of Insulators per Strings

Type of

Insulator

Contamination

Level

Number of Insulator by

Contamination

Design

Light

Impulse

Withstand

Voltage

Switching

Impulse

Withstand

Voltage

Result

U210B Heavy 15 17 14 17

(4) Mechanical Strength of Tension Insulators For the suspension towers, the number of insulator strings per set is either the same as, or double

the amount of, the 210kN insulators, which was determined in accordance with the transmission line

crossing places. As for the tension towers, the number of insulator strings per set is double the number

of 300kN insulators. The tension insulators must satisfy the safety factor at RUS for maximum

working tension at the standard span of 400 m, as follows.

Table 6.3-6 Tension Insulator Assembly Conductor

Maximum Tension


LL-ACSR 728 mm2 132.0kN (66.0kN × 2) Double strings 600kN

(300kN × 2) 4.54 > 2.5

(5) Tension Insulator Assembly Insulator assembly fittings also have to maintain the same strength as the insulators.

Table 6.3-7 Tension Insulator Assembly Conductor

Maximum Tension


LL-ACSR 728 mm2 133.0kN (66.0kN × 2) Double strings 600kN

(300kN × 2) 4.54 > 2.5

Ground Clearance The most severe state for the ground clearance of the conductors will occur when the conductor’s

temperature rises to 75 ºC under still air conditions. The minimum height of the conductor above

ground at 230 kV level is determined as below.

Table 6.3-8 Minimum Height of the Conductor above Ground Object Clearance

Ground (Paddy field) 8.0 m

Road 10.0 m

Railway 20.0 m

Determination of Tower Configuration

(1) Electrical Clearance

Table 6.3-9 Swing Angle and Insulation Clearance Normal Middle Abnormal

Wind velocity 0 to 10 m/s 10 to 20 m/s 20 to 35 m/s

Swing angle of suspension strings (A) 0 to 10 deg 10 to 30 deg 30 to 60 deg

Swing angle of tension strings without jumper

loop (B) 0 to 5 deg 5 to 15 deg 15 to 40 deg

Swing angle of tension strings with jumper

loop (C, D, E) 0 to 15 deg N/A N/A

Clearance (suspension strings) 2,760 mm 1,910 mm 700 mm

Clearance (tension strings) 2,530 mm 1,910 mm 700 mm

*The above figures considered the length of the step bolts and thickness of materials.



6-17

(2) Length of String Set and Drop of Jumper Loop The length of the suspension string set and drop of jumper loop are estimated as follows.

Table 6.3-10 Length of Suspension String Set and Drop of Jumper Loop Type Determination Length

Length of suspension string set

for U210B 170mm × 17units＋1,080mm (fitting length) 3,970mm

Length of tension string set for

U210B 170mm × 17units＋1,035mm (fitting length) 3,925mm

Drop of jumper loop for tension

string set 2,480mm* × 1.2＋100mm (influence of slope) 3,080mm

Length of support insulator

string set for C, D, 4C, E 170mm × 17units＋785mm (fitting length) 3,675mm

*Air clearance (Normal conditions): 2,480mm

(3) Clearance Diagram Clearance diagrams of suspension insulator strings and drop of jumper loop are shown below.

Suspension Tension

A B, 4B C, D, E, 4C

Figure 6.3-3 Clearance Diagram

Towers

(1) Types of Towers (a) Type A

Suspension type towers on straight sections of the line or on sections of the line with a

horizontal deviation angle up to 3 degrees with suspension insulator sets.

(b) Type 4A

4 circuits Suspension type tower on straight sections of the line or on sections of the line

with a horizontal deviation angle up to 3 degrees with suspension insulator sets.

(c) Type B

Tension type tower on sections of the line with a horizontal deviation angle up to 20

degrees with tension insulator sets.

(d) Type 4B

4 circuits tension type tower on sections of the line with a horizontal deviation angle up to

20 degrees with tension insulator sets.

(e) Type C

Tension type tower on sections of the line with a horizontal deviation angle from 20

degrees to 40 degrees with tension and jumper suspension insulator sets.

(f) Type 4C

4 circuits tension type tower on sections of the line with a horizontal deviation angle from

20 degrees to 40 degrees with tension and jumper suspension insulator sets.

(g) Type D

Tension type tower on sections of the line with a horizontal deviation angle from 40

degrees up to 60 degrees with tension and jumper suspension insulator sets.



6-18

(h) Type E

Tension type tower used at the terminal of the line with tension insulator sets having

jumper insulator sets where required, with a horizontal angle up to 40 degrees.

Table 6.3-11 Tower Types and the Applied Conditions Type Position of Use Angle of Deviation [deg.] String Type

A, 4A Straight line 0 – 3 Suspension

B, 4B Angle 4 – 20 Tension

C, 4C Angle 21 – 40 Tension

D Angle 41 – 60 Tension

E Terminal 0 – 40 Tension

(2) Design Span The design of all towers will provide for the following wind spans and weight spans.

Table 6.3-12 Design Span Tower Type Wind Span [m] Weight Span [m]

A, 4A 400 600

B, 4B 400 600

C, 4C 400 600

D 400 600

E 400 300

(3) Maximum Sag Calculation and Standard Heights of Towers Conductor temperature: 75 deg.

Wind pressure: still air

Table 6.3-13 Maximum Sag and Standard Heights of Towers (Proposal) Suspension type Tension type

Maximum conductor sag 13.3 m 13.3 m

Insulator length 4.0 m - m

Ground Clearance 10.0 m 10.0 m

Standard height of tower above

ground

(below bottom cross arm)

27.3 m 23.3 m



6-19

(4) Shape of Tower

Figure 6.3-4 Type A Tower Figure 6.3-5 Type B, C, D Tower

Figure 6.3-6 Type E Tower



6-20

Figure 6.3-7 Type 4A Tower Figure 6.3-8 Type 4B, 4C Tower

(5) Unit Weight of Towers The unit weights of towers for different extension lengths are shown below.

Table 6.3-14 Unit Weight of the 2 Circuit Towers

Tower extension

[m]

Unit weight of towers [ton]

A B C D E

0 23.8 32.0 38.3 42.2 48.4

+3 28.3 38.7 45.9 51.8 –

Table 6.3-15 Unit Weight of the 4 Circuit Towers

Tower extension

[m]

Unit weight of towers [ton]

4A 4B 4C

0 58.4 87.3 116.3



6-21

Tower Foundations

(1) Tower load conditions The foundation loads that are transmitted from each tower at ±0.0 m extension

Table 6.3-16 Tower Load Conditions (2 cct 230 kV）

Table 6.3-17 Tower Load Conditions (4 cct 230 kV）


[kN]

Tensile load

[kN]

4A 1619.9 1135.3

4B 2686.2 2016.8

4C 3960.1 3148.5

Quantities of the Transmission Line Materials

(1) Number of Towers and Total Weight of Towers The assumed tower types, number of towers and the tower weight for the transmission line are

summarized in the following table.

Table 6.3-18 Numbers of Towers and Tower Weight (Sar Ta Lin S/S to East Dagon S/S)


[m]

Unit weight

[ton]

No. of towers

[unit]

Total weight

[ton]

A: Suspension


0.0 23.8 33 785.4

+3.0 28.3 1 28.3

Subtotal 34 813.7

B: Tension


0.0 32.0 2 64.0

+3.0 38.7 – –

Subtotal 2 64.0

C: Tension


0.0 38.3 2 76.6

+3.0 45.9 1 45.9

Subtotal 3 122.5

D: Tension


+3.0 51.8 – –

Subtotal 4 168.8

E: Dead-end


Subtotal 2 96.8

Total 45 1265.8

Table 6.3-19 Numbers of Towers and Tower Weight (Sar Ta Lin S/S to Hlawga S/S)


[m]

Unit weight

[ton]

No. of towers

[unit]

Total weight

[ton]

4A: Suspension


Subtotal 33 1927.2

4B: Tension


Subtotal 3 261.9

4C: Tension


Subtotal 5 581.5


[kN]

Tensile load

[kN]

A 642.5 494.4

B 996.2 771.0

C 1438.0 1131.7

D 1855.1 1524.8

E 2122.3 1668.4



6-22

E: Dead-end


Subtotal 4 193.6

Total 45 2964.2

Table 6.3-20 Numbers of Towers and Tower Weight (Hlawga S/S to Thaketa S/S)


[m]

Unit weight

[ton]

No. of towers

[unit]

Total weight

[ton]

A: Suspension


0.0 23.8 38 904.4

+3.0 28.3 4 113.2

Subtotal 42 1017.6

B: Tension


0.0 32.0 4 128.0

+3.0 38.7 – –

Subtotal 4 128.0

C: Tension


0.0 38.3 1 38.3

+3.0 45.9 – –

Subtotal 1 38.3

D: Tension


0.0 42.2 – –

+3.0 51.8 – –

Subtotal – –

E: Dead-end

(Horizontal angle: 0 – 40 deg.) 0.0 48.4 4* 193.6

Subtotal 4 193.6

Total 51 1377.5

*2 type E towers branch to Kyaikkasan S/S.

(2) Quantities of Conductors and Ground Wire The quantities of conductors and ground wires for the transmission line are computed by

multiplying the numbers of conductors or ground wires by the route length, and multiplying that

number by 1.05 for the sag allowance and margin for stringing work.

Table 6.3-21 Quantities of Conductors and Ground Wire Conductor/Ground wire

type

No. of

bundles

No. of

phases

No. of

circuits

Route length

[km]

Line length

[km]

LL-ACSR 728 mm2

Sar Ta Lin – East Dagon

T/L 2 3 2 19.0 239.4

Sar Ta Lin – Hlawga T/L 2 3 4 17.0 428.4

Hlawga – Thaketa T/L 2 3 2 17.0 214.2

Total 882.0

OPGW115 mm2


T/L 1 – 1 19.0 19.95

Sar Ta Lin – Hlawga T/L 1 – 1 17.0 17.85

Hlawga – Thaketa T/L 1 – 1 17.0 17.85

Total 55.65

AC110 mm2


T/L 1 – 1 19.0 19.95

Sar Ta Lin – Hlawga T/L 1 – 1 17.0 17.85

Hlawga – Thaketa T/L 1 – 1 17.0 17.85

Total 55.65

(3) Quantities of Insulators and Insulator Assemblies The quantities of insulators and insulator assemblies for the three transmission lines are computed

from the number of suspension and tension towers considering the number of strings.



6-23

Table 6.3-22 Quantities of Insulators and Insulator Assemblies

Insulator

type Tower type

Assembly

type

No. of

insulators

per set [pcs]

No. of

strings per

tower [set]

No. of

tower

[unit]

Subtotal

of strings

[set]

Subtotal of

insulators

[pcs]

Sartalin – East Dagon T/L

U210B

Suspension Double 34 6 1 6 204

Single 17 6 33 198 3366


Tension Double 34 12 9 108 3672


Subtotal 390 8976

Sartalin – Hlawga T/L

U210B


Single 17 12 32 384 6528




Subtotal 744 16932

Hlawga – Thaketa T/L

U210B


Single 17 6 38 228 3876




Subtotal 390 8874

TOTAL 1524 34782

(4) Quantities of Foundation Concretes Quantities of reinforced concrete of the foundations for different types of 230kV towers based on

dfferent transmission lines are summarized in the following table.

Table 6.3-23 Quantities of Foundation Concretes Type of

foundation Tower type

Unit concrete

[m3]

No. of tower

[unit]

Total concrete

[m3]

Sartalin – East Dagon T/L

Pile

A 43.6 34 1482.4

B 44.0 2 88.0

C 45.6 3 136.8

D 45.6 4 182.4

E 45.6 2 91.2

Subtotal 45 1980.8

Sartalin – Hlawga T/L

Pile

4A 45.6 33 1504.8

4B 45.6 3 136.8

4C 150.0 5 750.0

E 45.6 4 182.4

Subtotal 45 2574.0

Hlawga – Thaketa T/L

Pile

A 43.6 42 1831.2

B 44.0 4 176.0

C 45.6 1 45.6

D 45.6 0 0.0

E 45.6 4 182.4

Subtotal 51 2235.2

TOTAL 141 6790.0

Table 6.3-24 Total Quantities of Insulators

Insulator type Total No. of insulators [pcs]

U210B 18462

U300B 9600



6-24

Obstacle Limitation Surface The height of the towers within the obstacle limitation surface of Yangon International Airport are

shown in Figure 6.3-9 and the height limitation of obstacles is illustrated in Figure 6.3-10. The height

of the towers (Hlawga – Thaketa T/L) within the 2.0% slope area must be within 60m and the height

of the towers (Sar Ta Lin – Hlawga T/L) within the horizontal area must be within 150m.

Figure 6.3-9 Obstacle Limitation Surface of Yangon International Airport

Figure 6.3-10 Illustration of the Limitation Surface

6.4. Design of Foundations

Soil Conditions Most of the 500 kV and 230 kV TL routes are Alluvium, which is new and relatively soft. Therefore,

pile foundations will be applied for most of the towers. In addition, we judged that pile foundations

were appropriate based on the results of boring logs shown in Figure 3.3-6 to Figure 3.3-11. It is

necessary to conduct a detailed soil investigation at each TL tower position before implementing the

detailed design to determine the type of each tower foundation and the depth of the support layer.

(1) Soil Conditions for Pile Foundations The concept for the supporting layer of pile foundations is in accordance with the Basic Design in

"500kV TRANSMISSION LINE BETWEEN PHARYARGYII AND HLAING THARYAR FOR

NATIONAL POWER TRANSMISSION NETWORK DEVELOPMENT PROJECT PHASE I". A



6-25

supporting layer should be a clay layer for which the N-value is 20 or more, or a sand layer, gravel or

rock for which the N-value is 30 or more.

The depth of supporting layer is BH1 (21.0m), BH2 (30.0m), BH3 (40.5m*), BH4 (28.5m), BH5

(40.5m*) and BH6 (40.5m*) based on boring logs shown in Figure 3.3-6 to Figure 3.3-11, and the

average depth is 33.5m. Here, the depths of 40.5 m in three logs - BH3, BH5 and BH6 - are considered

to be almost enough to satisfy the supporting conditions.

In addition, the following boring logs from near East Dagon SS, published on the website, were

referenced. The data source is "The Project for the Improvement of Water Supply, Sewerage and

Drainage System in Yangon City Vol IV Water Supply System Feasibility Study, Appendix". The depth

of the supporting layer is 33.0 m.

From the above results, the supporting layer depth of pile foundations in the Alluvium was estimated

to be about 33.0 m.

Figure 6.4-1 Location of Boring Logs near East Dagon SS

East Dagon S/S



6-26

Figure 6.4-2 Soil Conditions of Pile Foundation (1/5)



6-27




6-28




6-29




6-30




6-31

(2) Soil Conditions for Pad and Chimney Foundations Near Phayargi S/S, near the middle of the TL route between Pharyargyii S/S and Sar Ta Lin S/S is

the Irrawaddy Formation, which is relatively solid from Miocene to Pliocene. The TL route near

Phayargi S/S is shown in Figure 6.4-7. The TL route between Phayargi S/S and Sar Ta Lin S/S is

shown in Figure 6.4-8.

According to basic design in “500kV TRANSMISSION LINE BETWEEN PHARYARGYII AND

HLAING THARYAR FOR NATIONAL POWER TRANSMISSION NETWORK DEVELOPMENT

PROJECT PHASE I”, most of the tower foundations on Irrawaddy were Pad and Chimney, and the

soil conditions of this Irrawaddy were applied for Type II in Table 6.4-1.

Table 6.4-1 Classification of Foundations

Figure 6.4-7 Geology Near Phayargi S/S

Paddy field

4

IV

high

Paddy field

1 2 3

III

fewsubsoil water

15

10

0

100

130

Foundation type

Yielding bearing capacity

Unit weight of soil

Angle of repose

(kN/m3)Wc

ｗ

θ

(kN/m3)

(゜）

24

14

0

200300

20

16

24

250

Unit weight of concrete

750 400

Underground water level lowfew

subsoil water

Land use

(kN/m2)

We

30

II

Hilly area, Solid farm

Soft farm

I

Yielding bearing capacity for lateral force ｗf

Selective number for calculation

(kN/m2)

18

24

600

Irrawaddy

Alluvium



6-32

Figure 6.4-8 Geology between Phayargi S/S and Sar Ta Lin S/S

Loads Conditions for Pile Foundations The tower load conditions for 230kV TL are shown in Table 6.4-2 and those for 500kV TL are

shown in Table 6.4-3.

Legends by tower angle are shown below.

A： 0°～3° (Suspension)

B： 3°～20° (Tension)

C： 21°～40° (Tension)

D： 41°～60° (Tension)

E： 0°～40° (Terminal)

Table 6.4-2 Tower load conditions for 230kV TL

Irrawaddy

Alluvium



6-33

Table 6.4-3 Tower load conditions for 500kV TL

Results of Foundation Design The specifications and shape of the foundations need to be determined through a detailed design

based on the soil investigation results at each tower before construction. The basic design for the

foundations was conducted based on the current geological and loading conditions. In addition, the

depth of the support layer for the pile foundations was assumed to be 33m, where the N value becomes

24 or more in cohesive soil based on “Soil Conditions of Pile Foundation (4/5) in Table 6.4-4.

(1) Pile Foundations for 500kV (2 circuits) The dimensions of the pile foundations for 500kV (2 circuits) are shown in Table 6.4-4.



6-34

Table 6.4-4 Dimensions of the pile foundations for 500 kV (2 circuits)

(2) Pile Foundations for 230kV (2 circuits) The dimensions of the pile foundations for 230kV (2 circuits) are shown in Table 6.4-5.

DA DB DC DD DE

(a) m 0.60 0.75 0.75 0.75 0.75

(b) m 0.85 1.00 1.00 1.00 1.00

(f') m 0.50 0.50 0.50 0.50 0.50

(h1) m 1.50 1.50 1.50 1.50 1.50

(B) m 3.20 3.20 3.70 4.80 3.50

(t) m 1.00 1.00 1.00 1.00 1.00

(H) m 2.00 2.00 2.00 2.00 2.00

Length (L) GL-m 34.00 34.00 34.00 34.00 34.00

Diameter (D) mm 800 800 800 800 800

No. of Piles (n) - 4 4 4 4 4

Pad

Depth of Pad Bottom

Pile

Chimney

Tower Type



6-35

Table 6.4-5 Dimensions of the pile foundations for 230kV (2 circuits)

A B C D E

(a) m 0.55 0.60 0.75 0.75 0.75

(b) m 0.80 0.85 1.00 1.00 1.00

(f') m 0.50 0.50 0.50 0.50 0.50

(h1) m 1.50 1.50 1.50 1.50 1.50

(B) m 3.20 3.20 3.20 3.20 3.20

(t) m 1.00 1.00 1.00 1.00 1.00

(H) m 2.00 2.00 2.00 2.00 2.00

Length (L) GL-m 34.00 34.00 34.00 34.00 34.00

Diameter (D) mm 800 800 800 800 800

No. of Piles (n) - 4 4 4 4 4

Pile

Chimney

Pad

Depth of Pad Bottom

Tower Type



6-36

(3) Pile Foundations for 230kV (4 circuits) The dimensions of the pile foundations for 230kV (4 circuits) are shown in Figure 6.4-6.

Table 6.4-6 Dimensions of the pile foundations for 230kV (4 circuits)

4A 4B 4C

(a) m 0.75 0.75 0.75

(b) m 1.00 1.00 1.00

(f') m 0.50 0.50 0.50

(h1) m 1.50 1.50 1.50

(B) m 3.20 3.20 5.50

(t) m 1.00 1.00 1.20

(H) m 2.00 2.00 2.20

Length (L) GL-m 34.00 34.00 34.00

Diameter (D) mm 800 800 800

No. of Piles (n) - 4 4 4

Chimney

Pad

Depth of Pad Bottom

Pile

Tower Type



6-37

(4) Pad and Chimney Foundations for 500kV (2 Circuits) The dimensions of Pad and Chimney foundations for 500kV (2 circuits) are shown in Table 6.4-7.

Table 6.4-7 Dimensions of the Pad and Chimney foundations for 230kV (4 circuits)

DA DB DC DD DE

II II II II II

(a) m 0.60 0.80 0.80 0.80 0.80

(b) m 1.20 1.40 1.40 1.50 1.40

(f') m 0.50 0.50 0.50 0.50 0.50

(h1) m 3.50 3.60 3.90 4.00 3.80

(B) m 4.30 5.30 6.30 7.00 6.00

(t) m 1.00 1.00 1.00 1.00 1.00

(H) m 4.00 4.10 4.40 4.50 4.30

Geological Type

Chimney

Pad

Depth of Pad Bottom

Tower Type



6-38

6.5. Preliminary Design for Underground Transmission Lines

Design for Burial Method There are, in general, two types of underground transmission line systems: direct burial and duct

burial. The optimal construction method will be selected in consideration of economy, construction

period, surrounding environment, etc.

In particular, the duct burial method is effective for narrow roads in urban areas in order to prevent

traffic jams and avoid disturbing daily life, as it does not require a prolonged excavation because it

can be backfilled on the same day after excavating and installing duct pipes. The duct burial method

is basically examined at the preliminary design stages.

Source: JICA survey team

Figure 6.5-1 Overview of direct burial method and duct burial method


Figure 6.5-2 Overview of duct burial method


Figure 6.5-3 Horizontal Directional Drilling Method



6-39

Table 6.5-1 Evaluation of direct burial and duct burial method Direct burial Duct HDD

Length of one driving ◎

None

◎

None

△

Less than 1000m

Shaft Not needed Not needed Need for connection to next duct

Temporary Yard ◎

Dairy yard

◎

Dairy yard

△

Wide and Long Period (HDD

machine at start and end site)

Workability

△

Backfilling can

only be done after

installing the cable

◎

Backfilling can be done after

installing duct (the same day)

◎

No backfill

Maintenance ○

◎

Cable replacement is possible

in the event of an accident or

expansion

◎

Cable replacement is possible in

the event of an accident or

expansion

Cost (at the time of an

accident) △ ◎ ◎

Overall Evaluation ○ ◎ ○

Note: ◎---Very good, ○----Good, △----Not suitable Source: JICA survey team

Direct burial method and Duct burial method are evaluated via the items of workability,

maintenance, and cost (at the time of an accident) etc. The duct burial method does not require a

prolonged excavation because it can be backfilled on the same day after excavating and installing duct

pipes. After commissioning of the power cable, cable replacement in an accident and replacement of

old cables can be performed in the duct without digging the road. The duct burial method is more

advantageous than the direct burial method in terms of workability, maintenance and so on. The HDD

method is applied for crossing rivers and railways, which present difficulties in digging the road.

Design of Ducts The recommended material for duct pipes is Polyester Concrete Fiberglass Reinforced

Plastic Pipe (PFP), which is widely used in Japan for multi-pipe conduit.

Source: Kurimoto web site and so on

Figure 6.5-4 Overview of HDPE duct (right) and PFP duct (left)



6-40

Source: kurimoto web site

Figure 6.5-5 Overview of PFP duct

This table shows an evaluation of HDPE duct and PFP duct.

Table 6.5-2 Evaluation of HDPE duct and PFP duct

HDPE PFP

Workability ◎

Workers can carry one.

Easy handling by worker

Unit of straight length: 10m

Easy duct to duct connection

Weight: around 17kg/m

(nominal diameter: 250mm)

〇

Workers can carry one.

Heavier than HDPE

Unit of straight length: 2m

Weight: around 31kg/m (nominal diameter:

250mm)

Maintenance ◎ ◎

Strength △ Weaker than PFP and it has

never been used with pipe clieats.

◎ Resilient to outer damage with polycon

Fiber Reinforced and widely used with

pipe clieats in Japan.

Cost ◎ 〇

Overall

Evaluation △ ◎


Note: ◎---Very good, ◯----Good, △----Not suitable

HDPE ducts are more advantageous in terms of workability and cost. However, in this project nine

pipes will be arranged in horizontal 3 rows and vertical 3 rows with pipe clieats, so the recommended

material for duct pipes is Polyester Concrete Fiberglass Reinforced Plastic Pipe (PFP).

Design of Manholes and Joint Bays There are two types of cable connection construction methods for underground transmission lines:

the joint bay method (generally used abroad) and the manhole method (generally used in Japan). The

manhole method is expensive in terms of the initial construction costs, but maintenance costs can be

reduced by adopting the manhole system integrally with the duct pipe method, because cable

replacement in an accident and replacement of old cables can be performed from the manhole neck.

The manhole method is also effective for narrow roads in urban areas in terms of preventing traffic

jams and avoiding disturbances to daily life, because all maintenance work can be performed from the



6-41

manhole neck. This figure shows an overview of the joint bay and manhole.


Figure 6.5-6 Overview of Joint Bay

Source: TEPCO PG leaflet

Figure 6.5-7 Overview of Manhole

This table shows an evaluation of the Joint Bay and Manhole.

Table 6.5-3 Evaluation of Joint Bay and Manhole Joint Bay Manhole

Workability ○ ◎

Cable joint work in a manhole is not affected by weather conditions with workers entering from the manhole neck

Maintenance △ ◎

Maintenance of cables in the manhole and replacement of cables in an accident with workers entering from the manhole

Expandability △ ◎ It is possible to expand the duct and make branch ducts in the future

Cost (at the time of an accident） △ ◎

Overall Evaluation ○ ◎

Note: ◎---Very good, ○----Good, △----Not suitable

Joint

Joint

Joint

Manhole

Cable Jointing



6-42


The Manhole method is superior to the Joint Bay method in terms of workability and maintenance,

with the maintenance staff entering the manhole through manhole neck. With a manhole, it is possible

to expand the duct and make branch ducts in the future, so the Manhole method is superior to the Joint

Bay method in terms of expandability.

After commissioning of the power cable, cable replacement in an accident and replacement of old

cables can be performed in the duct without digging the road. The duct burial method is more

advantageous than the direct burial method in terms of workability, maintenance and so on.

The manhole method is expensive in terms of the initial construction costs, but maintenance costs

can be reduced by adopting the manhole system integrally with the duct pipe method, because cable

replacement in an accident and replacement of old cables can be performed from the manhole neck

without digging the road. Furthermore, if a manhole is made in a precast system, manufactured at a

local plant and installed at the site using a truck crane, the construction period can be significantly

shortened, and it is also possible to reduce the impact of construction on the surrounding environment.

Figure 6.5-8 Overview of precast manhole

The features of precast manholes are as follows.

Molding concrete with reinforced rod into precast manhole in factory

Each piece of precast manhole is connected with a bolt at the construction site

Attach rubber packing along the Jointing

Waterproof treatment to the surface of molding concrete

Jointing with mortar at the construction site

Design of Cable The recommended material for the 230kV Cable is cross-linked polyethylene insulated vinyl sheath

cable (XLPE cable), which is the dominant material used abroad.

Cable conductor size is calculated via required transmission capacity after confirmation of

conditions. The optimal cable specification is selected taking the employer’s needs, site conditions

and so on into consideration. This figure shows two types of cable, with aluminum sheath and lead

sheath.



6-43


Figure 6.5-9 Typical cross-section of Extra High Voltage cable with different metallic sheath (left figure: lead sheath, right figure: Aluminum sheath)

This table shows an evaluation of cable specifications with different metallic sheaths.

Table 6.5-4 Evaluation of cable specifications with different metallic sheaths

Type of metallic sheath Lead alloy Extruded corrugated

Aluminum

Short-current of

Xx kA - y second

○: Additional copper wire layer is

required ◎

Continuous Current Capacity ◎ ◎

Water Impermeability ◎ ◎

Corrosion in Water ◎: Steady ○:Sensitive

Flexibility ◎ ◎:Required annular

shaped corrugation

Weight of Cable ○: (As 100%)

◎: (Approx.60- 70%)

[Less Cable pulling tension,

compared to lead sheath]

Mechanical Protection ○ ◎

Cost ○ (As 100%) ◎：（Approx.80－90%）

Environmental Effects △:Toxic ◎

Overall Evaluation ○ ◎

Note: ◎---Very good, ○----Good, △----Not suitable Source: JICA survey team

For the cable, there are concerns about corrosion in terms of sensitivity to water, but the cable can

be covered by an outer sheath. In view of the permissible short circuit current, cable with an extruded

corrugated aluminum sheath is more advantageous than lead sheath in terms of workability (30% less

weight than lead sheath) and cost (approximately 10 – 20 % less than lead sheath).

Preliminary Design

(1) Basic Conditions for Design

Basic Conditions (Common Items) This table shows the basic conditions for the preliminary design. The route for the underground

transmission line is shown in Chapter 3. Required transmission capacity is in accordance with Chapter

1.



6-44

Table 6.5-5 Basic conditions for design

Item Value Unit Remarks

Voltage 230 kV

Number of circuits 4 Circuit Sar Ta Lin SS – Hlawga SS

2 Circuit Hlawga SS – Thaketa SS

Maximum conductor

temperature

90 Centigrade

Maximum ambient

temperature in tunnel

40 Centigrade

Wind velocity in tunnel Less than

3

m/s Maximum wind velocity during work

(TEPCO guidelines)

Air temperature at

ventilation tower

28 Centigrade

Ambient temperature of

soil

30 Centigrade IEC60287-3-1

Thermal resistivity of soil 1.0 K.m/W IEC60287-3-1

Necessity network fault

current and continuous

time

40 ☓ 1 kA ☓ sec Earth fault

40 ☓ 3 kA ☓ sec Phase fault


The ambient temperature of soil and thermal resistivity of soil is decided in accordance with

IEC60287. These tables show the ambient temperature of soil and thermal resistivity of soil in IEC

standards.

Table 6.5-6 Ambient temperature of soil

Climate

Ambient temperature of soil at depth of 1m

Unit: ℃ (centigrade)

Min Max

Tropical 25 40

Subtropical 15 30

Temperate 10 20 Source: IEC60287

Table 6.5-7 Thermal resistivity of soil

Thermal resistivity of

soil (K.m/W)

Soil Conditions Weather Conditions

0.7 Very Moist Continuously moist

1.0 Moist Regular rainfall

2.0 Dry Seldom rain

3.0 Very Dry Little or no rain Source: IEC60287

The climate in Myanmar is an almost subtropical climate, and 30° C is selected as the maximum

ambient temperature of soil.

For thermal resistivity of soil, Myanmar has a rainy season and a dry season, and 0.7 K.m/W is

selected when considering only the rainy season. However, there are also dry periods in the year, and

1.0Km/W may be selected considering safety.

The cable selected is single core type 2500mm2 with corrugated aluminum sheath. This table shows

the technical particulars of the cable.



6-45

Table 6.5-8 Technical Particulars of the selected 230kV 1C Cable

Item Unit Particulars

Conductor

Size mm2 2500

Material - Copper

Shape - Segmental Compact round

Diameter mm 62.2

Thickness of conductor shielding mm 1.5

Thickness of insulation mm 22

Thickness of semi-conductive layer mm 2

Alu

min

um

sh

eath

Thickness of swellable layer mm 1.9

Diameter over the cable core mm 117

Thickness of Al-sheath mm 2.5

Average diameter of Al-sheath mm 126.52

External diameter of Al-sheath mm 136.04

Thickness of PE jacket layer mm 5

Outside diameter of cable mm 151

Estimated unit weight of cable Kg/m 36

DC conductor resistance at 20℃ Ω/km 0.0072

Electro-static capacitance at 20℃ μF/km 0.25


Calculation of transmission capacity for cable conductor size Calculation in normal operation is carried out in accordance with IEC60287. Calculation of short

circuit rating is carried out based on IEC60949.

The necessary conditions for the design are as follows:

1) Number of circuits

2) Continuous current rating (MVA/circuit or ampere)

3) Ambient temperature of soil (degrees centigrade)

4) Thermal resistivity of soil

5) Necessity network fault current and continuous time (kA, sec)

Design for ducts and tunnels The study team uses the “duct burial system” in sections of 2 circuits between branch towers to the

NH3 road, for every underground transmission line, taking the results of the calculation of

transmission capacity into consideration. This is identified as an appropriate distance between ducts

(cables).

The study team uses the “tunnel system” in sections of more than 4 circuits between the MH3 road

to Hlawga substation, taking the results of the calculation of transmission capacity into consideration.

This is identified as an appropriate distance between cables in a tunnel. A ventilation system is applied

for tunnels, with ventilation towers to secure the state temperature in tunnels. The interval between

ventilation towers is around 500m.



6-46


Figure 6.5-10 Conceptual diagram of Underground transmission system

Manhole design Manhole design is carried out after the decision on cable conductor size via a calculation of the

required transmission capacity. Manhole design is carried out in accordance with the permissible

bending radius of cable (15D: D is the overall diameter of the cable). The necessary manhole size is

also decided.

(2) Results of the Calculation of the Capacities based on the Power Flow in 2027 This sections shows the results of the calculation of the capacities based on the following

assumptions of the power flows in 2027 (Figure 1.5-13).

Sar Ta Lin SS – Hlawga SS: 770 MVA for 4 circuits

Hlawga SS – Thaketa SS: 430 MVA for 2 circuits

Results of calculation (Duct burial system) This table shows the results of the calculation in accordance with IEC60287, with a cable conductor

size of 2500mm2. Other conditions are as follows:

Depth of duct from ground: 1.2m

Distance ducts: 345mm (manufacturer’s standard)

Table 6.5-9 Result (Duct system: Sar Ta Lin - Hlawaga)


The number of circuits is 4. Conductor temperature is 42 centigrade at normal operation to around

Operational conditions Transmission

capacity

(MVA/circuit)

Number of

circuits

Total

(MVA)

Conductor

temperature

(Centigrade)

Normal 200 2 400 42

N-1 622 1 622 90



6-47

400MVA/2 circuits of each route. This result is good because it is less than 90 centigrade. In the case

of N-1 operation, the result of the calculation is 622MVA at 90 centigrade conductor temperature. This

result is good as it is more than 400MVA, which is the required transmission capacity.

Required transmission capacity from Thaketa to Hlawga is 423MVA per 2 circuits at normal

operation. This table shows the results of the calculation for Thaketa to Hlawga in the duct system.

Conductor temperature is 44 centigrade at normal operation to around 440MVA/2 circuits. This result

is good because it is less than 90 centigrade. In the case of N-1 operation, the result of the calculation

is 622MVA at 90 centigrade conductor temperature. This result is good as it is more than 430MVA,

which is the required transmission capacity.

Table 6.5-10 Results (Duct system: Thaketa - Hlawga)


Results of calculation (Tunnel system) It is necessary to carry out the calculation to maintain the state temperature in the tunnel. It is also

necessary to take the inlet temperature from the ventilation tower and the interval of ventilation towers

into consideration.

Monthly average temperature in Yangon city between Jan. 2013 to Jan. 2020 is as follows:

Average temperature: 27.6 degree centigrade

Average high temperature: 33.5 degree centigrade

Average low temperature: 21.7 degree centigrade

This figure shows three average temperatures between Jan. 2013 and Jan. 2020 in Yangon city.

Average temperature is less than 30 degree centigrade between the terms. 28 degree centigrade is

appropriate for inlet air temperature from ventilation tower to tunnel.

Source: JICA survey team arrangement based on the Japan Meteorological Agency website

Figure 6.5-11 Monthly average temperature in Yangon city

An appropriate state temperature is maintained by this ventilation system, which locates ventilation

towers on the tunnel between Hlawga and the NH3 road. The ventilation system is set with a fan in

ventilation towers. The interval between ventilation towers is around 500m. The disposition of three

Phase cable is trefoil in tunnels.


capacity

(MVA/circuit)

Number of

circuits

Total

(MVA)

Conductor

temperature

(Centigrade)

Normal 220 2 440 44

N-1 622 1 622 90



6-48

1) Results for normal operation (Power flow in 2027, Figure 1.5-13)

This table shows the results of the calculation for the tunnel system.

Table 6.5-11 Results (Tunnel system: Sar Ta Lin - Hlawga)

Table 6.5-12 Tunnel (Tunnel system: Hlawga –Thaketa)


In conditions of maximum tunnel temperature, 40 degree centigrade, conductor temperature is less

than 90 degree centigrade. This result secures the required transmission capacity of 200MVA and

220MVA.

The next step is to carry out calculations for required wind velocity in conditions of 500m intervals

of ventilation towers to maintain less than 40 degree centigrade in the tunnel.

Table 6.5-13 Wind velocity in tunnel (Normal operation)



Figure 6.5-12 Interval of ventilation towers and Air Temp. (1.1 m/s)

Required wind velocity in tunnels is 1.1m/s to maintain less than 40 degree centigrade in tunnels.

The next calculation is for N-1 operation.

Operational

conditions

Transmission

capacity

(MVA/circuit)

Number of

circuits

Total

(MVA)

Conductor

temperature

(deg. C)

Normal 200 4 800 47

Operational

conditions

Transmission

capacity

(MVA/circuit)

Number of

circuits

Total

(MVA)

Conductor

temperature

(Centigrade)

Normal 220 2 440 48


capacity

(MVA/route)

Total heat loss

(W/cm)

Required wind

velocity

(m/s)

Sar Ta Lin – Hlawga 800 1.1 1.1

Thaketa - Hlawga 440 0.6



6-49

2) Results for N-1 conditions (Sar Ta Lin – Hlawga) (Power flow in 2027, Figure 1.5-13)

This table shows the results of the calculation in the case of N-1 conditions (Sar Ta Lin – Hlawga).

Table 6.5-14 Results of calculation for N-1 (Sar – Hlw) in 2027


Table 6.5-15 Wind velocity in tunnel (N-1 Sar - Hlw)



Figure 6.5-13 Interval of ventilation towers and Air Temp. (N-1 Sar - Hlw)

Conductor temperature is 50 centigrade and less than 90 centigrade in the case of N-1 conditions.

Required wind velocity in tunnels is 1.4m/s to maintain less than 40 degree centigrade in tunnels, with

500m intervals between ventilation towers.

3) Results for N-1 conditions (Thaketa – Hlwaga) (Power flow in 2027, Figure 1.5-13)

This table shows the results of the calculation in the case of N-1 conditions (Thaketa – Hlwaga).

Conditions Transmission

capacity

(MVA)

Circuits Conductor

temperature

(Centigrade)

Sar Ta Lin – Hlawga

(N-1)

4 circuits --> 3 circuits

800 3 50

Thaketa – Hlawga 440 2 48

Line Transmission

capacity

(MVA/route)

Total heat loss

(W/cm)

Required wind

velocity (m/s)

Sar Ta Lin – Hlawga

(N-1)

4 circuits --> 3 circuits

800 1.4 1.4

Thaketa - Hlawga 440 0.6



6-50

Table 6.5-16 Results of calculation for N-1 (Tha – Hlw) in 2027

Table 6.5-17 Wind velocity in tunnel (N-1 Tha - Hlw)



Figure 6.5-14 Interval of ventilation towers and Air Temp. (N-1 Tha - Hlw)

Conductor temperature is 62 centigrade and less than 90 centigrade in the case of N-1 conditions.

Required wind velocity in tunnels is 1.5m/s to maintain less than 40 degree centigrade in tunnels, with

500m intervals between ventilation towers.

(3) Results of the calculation of the capacities based on the power flow in 2030

Study for normal conditions 230kV underground transmission lines capacities are calculated based on the power flow in 2030

(Figure 1.5-14).

1) Normal conditions in 2030

Sra Ta Lin – Hlawga: 1492MVA (373MVA×4 circuits)

Thaketa – Hlawga: 777MVA (388MVA×2 circuits)

◎Results of calculation (Duct burial system)

Permissible transmission capacity is 527MVA per circuit at 90 centigrade in normal operation for

the duct burial system.

Conditions Transmission

capacity

(MVA)

circuit Conductor

temperature

(Centigrade)

Sar Ta Lin – Hlwaga 800 4 47

Thaketa – Hlwaga

(N-1)

2 circuits --> 1 circuit

440 1 62

Line Transmission capacity

(MVA)

Total heat loss

(W/cm)

Required wind

velocity (m/s)

Sar Ta Lin - Hlwaga 800 1.1

1.5 Thaketa - Hlawga

(N-1)

2 circuits --> 1 circuit

440 1.1



6-51

Table 6.5-18 Results of calculation for Duct burial system


Sar Ta Lin – Hlwaga 373MVA < 527MVA

Thaketa – Hlwaga 388MVA < 527MVA

This figure (527MVA) is enough to meet the demand (373MVA and 388MVA) in normal

operation in 2030 for the duct burial system.

◎Results of calculation (Tunnel system)

This table shows the results of the calculation for cables with trefoil formation in the tunnel

system.

Table 6.5-19 Results of calculation for Tunnel system (trefoil)


The required velocity to keep the temperature in the tunnel below 40 centigrade is 3.1 m/ s, which

exceeds the allowable wind speed in the tunnel of 3.0 m/s.

Cable spacing is secured between conductor axes of more than the Cable Diameter and a

recalculation was carried out to reduce the total heat loss generated from the cable in the tunnel.

The cable spacing is 200 mm.

Table 6.5-20 Results of calculation for Tunnel system (phase separation)


This result is enough to meet the demand (1492MVA and 777MVA) in normal operation in 2030

for the tunnel system. Temperature in the tunnel is 40 centigrade. Required wind velocity is 2.2m/s.

◎Results

These results are enough to meet the power flow in 2030 in normal operation for the duct burial

sections and tunnel sections.

Sra Ta lin – Hlawag: 1492MVA (373MVA×4 circuits)

Conditions Permissible

transmission

capacity

(MVA/circuit)

Number of

circuits

Total

capacity

(MVA)

Conductor

temperature

(Centigrade)

Normal 527 2 1054 90

Name of line Transmission

capacity

(MVA)

Total heat loss

(W/cm)

Temperature in tunnel

(Centigrade)

Required wind

velocity (m/s)

Sar Ta Lin – Hlwaga 1492 3.3 40.0 3.1

Thaketa – Hlawga 777 1.8

Name of line Transmission

capacity

(MVA)

Total heat loss

(W/cm)

Required wind

velocity(m/s)

Sar Ta Lin – Hlwaga 1492 2.3 2.2

Thaketa – Hlawga 777 1.2



6-52

Thaketa – Hlwaga: 777MVA (388MVA×2 circuits)

Sar Ta Lin – Hlwaga in the case of N-1 conditions 230kV underground transmission line capacities are calculated in the case of N-1 for the Sar Ta Lin

– Hlwaga line.


Figure 6.5-15 Conceptual diagram of Underground transmission system (N-1 Sar – Hlw)


This table shows the permissible transmission capacity for N-1 conditions in duct sections.

Table 6.5-21 Results of calculation in Duct for N-1 (Sar – Hlw)


Permissible transmission capacity is 622MVA per circuit in the case of N-1 (Sar Ta Lin – Hlwaga)


This table shows the permissible transmission capacity of Sar Ta Lin (3 circuits) in the case of

N-1 conditions with an indication of the transmission capacity for the Thaketa - Hlwaga line (2

circuits), which is installed in the same tunnel as the Sar Ta Lin – Hlwaga line. Wind velocity is

2.9m/s.

Condition Permissible

transmission

capacity

(MVA/circuit)

Conductor

temperature

(Centigrade)

N-1 622 90



6-53

Table 6.5-22 Results of calculation for Tunnel (N-1 Sar – Hlw)

Transmission capacity (MVA)

Thaketa -

Hlwaga 0 796

Sar Ta Lin

- Hlwaga 1912 1581


Transmission capacity of the Sar Ta Lin – Hlwaga line is 1912MVA in tunnel sections at 0MVA

capacity of the Thaketa – Hlwaga line. However, transmission capacity of the Sar Ta Lin line is

1581MVA (527MVA x 3 circuits) in the duct burial section. Permissible transmission capacity

of the Sar Ta Lin line is 1581MVA in N-1 conditions.

◎Results

Permissible transmission capacity of the Sar Ta Lin – Hlwaga line is 1581MVA in the case of

N-1 conditions. Therefore, transmission capacity of the Thaketa – Hlwaga line is 796MVA.

Thaketa – Hlwaga in the case of N-1 conditions

230kV underground transmission line capacities are calculated in the case of N-1 for

the Thaketa – Hlwaga line.


Figure 6.5-16 Conceptual diagram of Underground transmission system (N-1 Tha – Hlw)


This table shows the permissible transmission capacity for N-1 conditions in duct sections.



6-54

Table 6.5-23 Results of calculation in Duct for N-1 (Tha – Hlw)


Permissible transmission capacity is 622MVA per in the case of N-1 (Thaketa – Hlwaga).


This table shows permissible transmission capacity for the tunnel system.

Permissible transmission capacity is 828MVA per circuit at maximum conductor temperature.

Table 6.5-24 Results of calculation of permissible transmission capacity for Tunnel


This table shows permissible transmission capacity for the Thaketa – Hlwaga line (1 circuit)

in the case of N-1 conditions, with an indication of the transmission capacity for the Sar Ta Lin

line (4 circuits), which is installed in the same tunnel as the Thaketa – Hlwaga line. Wind velocity

is 2.9m/s.

Table 6.5-25 Results of calculation for Tunnel (N-1 Tha – Hlw)

Transmission capacity (MVA)

Sar Ta Lin -

Hlwaga 1418 1492

Thaketa -

Hlwaga 828 777


Permissible transmission capacity for the Thaketa – Hlwaga line is 828MVA in N-1 conditions.

Then transmission capacity of the Sar Ta Lin line is 1418MVA.

◎Results

Permissible transmission capacity of the Thaketa – Hlwaga line is 828MVA in the case of N-1

conditions. Then transmission capacity of the Sar Ta Lin line is 1418MVA. The figure of 828MVA

is defined for tunnel sections. In actual fact, the permissible transmission capacity of the Thaketa

– Hlwaga line in the case of N-1 conditions is 622MVA because of the limited transmission

capacity of 622MVA in duct sections.

This figure shows the ventilation system to meet the power flow in 2030. Ventilation fans may

be required for each ventilation tower.

Condition Permissible

Transmission

Capacity

(MVA/circuit)

Conductor

temperature

(Centigrade)

N-1 622 90

Permissible

transmission capacity

(MVA/circuit)

Conductor

temperature

(Centigrade)

828 90



6-55

Figure 6.5-17 Example of ventilation system (cross section)


Figure 6.5-18 Example of ventilation system (plane figure)

(4) Design for short and ground fault currents The study team calculates for short and ground currents in accordance with IEC 60949. The below

two tables show the other conditions.

Table 6.5-26 Basic conditions (Short fault) for conductor

Item Unit Description Remarks

S mm2 2500 for copper conductor

θf deg. C 250 final temperature

θi deg. C 90 initial temperature

Table 6.5-27 Basic conditions (Ground fault)

for metallic sheath

Item Unit Description Remarks

S mm2 1820 for aluminum sheath

θf deg. C 150 final temperature

θi deg. C 85 initial temperature



6-56

Table 6.5-28 Results for short and ground faults

Permissible short-circuit current and

continuous time

Necessity network fault and continuous

time

Conductor 208kA > 40kA 3sec 40kA 3sec

Metallic sheath 122kA > 40kA 1sec 40kA 1sec


This result indicates that characteristics of the conductor and metallic sheath meet those for short

and ground fault currents.

(5) Design for Ducts Duct dispositions are basically designed with 345mm intervals from the results for transmission

capacity and the manufacturer’s standards. There are two types of duct material: PFP and HDPE. PFP

is more advantageous than HDPE in terms of strength. This figure shows the standard positons for

ducts.


Figure 6.5-19 Standard distance for ducts (left) and Spacer (right)

This table shows standard depth and other specifications.

Table 6.5-29 Duct specifications

Item Value Remarks

Standard depth 1200 mm

Duct Interval 345 mm Refer to spacer catalog

PFP

φ250

Outer diameter 286 mm

Inner diameter 250 mm


(6) Design of Tunnel Cut and Cover Tunnels (Box Culvert Tunnel) or Non-Cut and Cover Tunnels (Shield Tunnel) can

be considered for tunnel methods for Underground TL 230kV 6-circuit and 4-circuit sections from

Hlawga S/S to Sar Ta Lin S/S.

A comparison table of tunnel construction methods is shown in Table 6.5-30. In

consideration of the impact on the surrounding area, road width, traffic congestion,



6-57

noise and vibrations from the 230kV 6-circuit and 4-circuit sections, Non-Cut and

Cover Tunnels (Shield Tunnel) are proposed. A cross section of a Shield Tunnel with

jointing cables in the tunnel is shown in Source: JICA survey team

Figure 6.5-20.

Table 6.5-30 Comparison table of tunnel construction methods



Figure 6.5-20 Cross section of Shield Tunnel

Per the survey results for the existing buried underground TL from Hlawga S/S to Sar Ta Lin S/S,

the following existing buried facilities were confirmed on the underground TL route. The detailed

report on existing facility investigation for the underground TL route is to be referred attached “Final

Report for Route Study and Geological Survey for Transmission Lines under The Republic of the

Union of Myanmar National Power Transmission Network Development Project - Preliminary Survey

& Site Survey for Underground Transmission line on Phase III project”.



6-58

The vicinity of Hlawga S/S

・Φ14” Gas Pipe (Steel) Depth = 6 feet; Crossing Pyay Road

・Φ30” and Φ14” Gas Pipe (Steel) Depth = 6 feet; Buried on the sidewalk of Brochan Road


Figure 6.5-21 Existing facilities in the vicinity of Hlaga S/S

The vicinity of the middle of Hlaga S/S and No. 3 Main Road

・Φ60” Water Pipe (Steel) Depth = 1.7m; Crossing Brochan Road

・Φ30” Gas Pipe (Steel) Depth = 0.7m; Crossing Brochan Road

・Φ30” and Φ14” Gas Pipe (Steel) Road Level; Buried on the sidewalk of Brochan Road

・Φ32” Water Pipe (HDPE) Depth?; Buried on the sidewalk of Brochan Road

・Φ24” Water Pipe (Ductile) Depth?; Buried on the sidewalk of Brochan Road


Figure 6.5-22 Existing facilities in the vicinity of the middle of Hlaga S/S and No. 3 Main Road

The vicinity of the intersection of Brochan Road and No. 3 Main Road

・Φ30” Gas Pipe (Steel) Depth?; Crossing No. 3 Main Road



6-59

・Φ24” Water Pipe (Ductile) Depth?; Buried on the sidewalk of Brochan Road

・Φ48” Water Pipe Depth?; Crossing Brochan Road

・Water Valve and Manholes; Buried on the sidewalk of Brochan Road


Figure 6.5-23 Existing facilities in the vicinity of the intersection of Brochan Road and No. 3 Main Road

The schematic longitudinal section of the Shield Tunnel is shown inSource: JICA survey team

Figure 6.5-24. The boring logs for Hlawga S/S shown in Figure 3.3-28 are adopted. The

groundwater level is estimated to be 4.1m below the ground surface, and the target soil for the Shield

Tunnel is sandy soil with an N value of about 8. The depth of tunnel is determined to be 5.0m

considering existing facilities and the impact on the ground surface due to tunnel excavation.

It will be necessary to consider the results of surveys on existing buried facilities and the results

regarding the cable installation method at the detailed design stage.


Figure 6.5-24 Longitudinal section of Shield Tunnel

(7) Design for Manholes

Manhole design is carried out in accordance with the permissible bending radius of cable (15D: D

is the overall diameter of cable -> around 2300mm). This figure shows a Manhole for a cable joint of

2 circuits and 6 circuits.

Manhole for 2 circuits: length 12.5(m) height 3.4(m) width: 2.1(m)

Manhole for 6 circuits: length 15(m) height 5.7(m) width: 2.5(m)



6-60

A cable joint is fabricated in each manhole in each section of ducts (2 circuits).


Figure 6.5-25 Standard type of manhole (2 circuits)


Figure 6.5-26 Standard type of manhole (6 circuits)

The tunnel for 6 circuits is built using the shield method. A cable joint is fabricated in a tunnel (6

circuits).


Figure 6.5-27 Cable joint in Tunnel

Joint Box

Around 130m/3 circuits



6-61

Figure 6.5-28 Cable joint in tunnel (cross section)

(8) Overall construction schedule for transmission line This figure shows a tentative schedule for civil and cable work. Civil construction is the first step.

Cable installations are implemented after civil work for the section of duct as soon as possible. Then,

cable installations in the tunnel are implemented after the civil work for the shield tunnel.


Figure 6.5-29 Overall construction schedule for cable


Figure 6.5-30 Overall construction schedule for civil work

Joint Box for 1

Phase

(Month)

Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Civil work

Survey and Design

Preparation for work

Installation for cable (Duct) 3teams

Fabrication for cable joint(Duct) 1team/circuit

Inatallation(Tunnel) 3teams

Fabrication for cable joint(Duct) 1team/circuit

Incidential work

Final site test

(month)

Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Design

Preparation for work

Starting Shaft1

Starting Shaft2

Arriving Shaft1

①Shield Tunnel (2.3km)

②Shield Tunnel0 (0.9km)

Ventolaton Tower

Cable work

Restoratiojn for road

BuildingBuilding

Building

shoring

shoring

shoring



6-62

6.6. Substations

General The JICA Survey Team has visited the candidate substation sites and confirmed the availability and

technical viability of the new constructions and extensions, and carried out basic designs for each

substation as described in the subsequent sections.

Design Concepts The following concepts shall be applied to the design of substations to maximize their functions:

(1) General Concept Daily operation and maintenance (O&M) shall be performed safely and in accordance with

approved procedures.

The connection shall be made as simple as possible without affecting the required

performance from installed substation equipment.

If a fault occurs in a substation, the extent of the fault’s impact shall be kept to a minimum,

and the necessary switching operation for shifting loads to other substations shall be

performed immediately, without delay or trouble.

Design considerations must include facilitating future reinforcement and/or augmentation,

when necessary.

Design must be technically and economically feasible.

(2) Type of Substation The standard substation in Myanmar is, in principle, an outdoor type with conventional equipment.

An outdoor type substation is a substation with major facilities, such as main transformers, switchgear

instruments, etc. installed in the open air.

Other options for switchgear are gas-insulated switchgear (GIS) or Hybrid gas-insulated switchgear

(H-GIS). A GIS system requires only 15% of the space necessary for an air-insulated switchgear (AIS)

system, and an H-GIS system, to be applied to Pharyargyii substation in Phase 2, requires 70%. The

costs for the GIS system and buildings, however, are twice those of the AIS system. The GIS system

is mostly suitable for areas with space constraints, such as city centers, industrial areas, etc. or areas

with high air pollution levels.

The basic design considers AIS systems for outdoor, as well as GIS or H-GIS systems depending

on installation requirements and site conditions.

(3) Busbar Arrangement Currently, a one and a half circuit breaker arrangement for 500 kV switchgear and

double busbar arrangement for 230 kV switchgear are employed for the substation

systems in Myanmar, including the Phase 2 project. Therefore, the busbar arrangement

shall be carefully decided considering the following:

- Existing busbar arrangement (in case of extension)

- Supply reliability and security

- Operational performance and flexibility

- Capital costs

- Maintenance and repair requirements

- Space requirements Source: JICA SURVEY TEAM

Figure 6.6-1 One and a Half CB Arrangement

(4) Main Transformers The main transformers which will be installed in the new 500 kV substation are of an

oil-immersed type with on-load tap changer. Three units with single phase transformer (auto

transformer) and with star-star-delta (Y-Y-Δ) winding connections are applied for the main

transformers. Natural oil circulation and natural air cooling (ONAN) conventions and/or a natural oil

circulation and forced air cooling (ONAF) system is applied for the cooling system of the main

transformers.

The unit capacity and number of units of main transformers in a substation are determined

DS

CB

DS

DS

CB

DS

DS

CB

DS

Busbar #1

Busbar #2



6-63

comprehensively taking into account the results of the system analysis in Chapter 1.

(5) Short-Circuit Fault Current Capacity Short-circuit fault current capacity for substation facilities will be determined via the results of the

system analysis. However, in the case of expansion of an existing substation, the rated short-circuit

fault current shall be the same as that of the existing substation or the transmission feeder of the

connected substation.

(6) Transmission Line Protection Protection relays for 500 kV and 230 kV transmission lines are designed with dual protection in

accordance with existing facilities in Myanmar, as follows:

500 kV Transmission Line Protection

Main Protection 1 : Differential Relay (87)

Main Protection 2 : Distance Protection (21)

Back-up Protection : Overcurrent and ground fault protection (50/51N)

230 kV Transmission Line Protection

Main Protection 1 : Differential Relay (87)

Main Protection 2 : Distance Protection (21)

Back-up Protection : Overcurrent and ground fault protection (50/51N)

(7) Control Equipment We understand that there is a vision to collect all data/information from power plants and substations

in Myanmar at the National Control Center (NCC) located in Nay Pyi Taw, and there is a guiding

principle that the equipment for collecting data/information shall be based on IEC 61850. Under these

circumstances, we will propose to configure the Substation Automation System (SAS) based on IEC

61850 after careful confirmation of the intentions and planning by the Myanmar side.

Source: JICA Survey Team

Figure 6.6-2 System Configuration of Substation based on IEC 61850

(8) Tele-protection system Optical telecommunication via OPGW for the main system and Power Line Communication (PLC)

as a back-up system are used in Myanmar. Therefore, the telecommunication system in this Project is

basically an Optical telecommunication system with OPGW, and a PLC system will also be considered,

if necessary.

(9) Other Concepts 1) Earthing system

In the switchyard of the new substation, an underground earthing system should be properly laid in

the form of a meshed grid. In the case of extension of an existing substation, the new earthing system

should connected the existing system.

Station Level Control

Bay Level Control

Process Level Control

Ethernet Switch

ICU

VT CT

MU

VT CTCB

ICU

CB

IEDBay Controller IED IEDBay Controller IED

SCADA CPU GatewayWork

StationNCC

InternetSystem Configuration of

SCADA Based on IEC61850

- Pos s ib le to a c hi ev e th e

u n i f i e d p r o te c t i o n o f e a c h

substation in NCC by digitalizing

all signals from facility level in

substation to high-order system.

- Easy interface because all

signals including measured value

and communication between all

devices are connected in digital

telecommunication network

IED: Intelligent Electronic Device

MD: Merging Unit

ICU: Intelligent Control Unit

CB: Circuit Breaker

CT: Current Transformer

VT: Voltage Transformer

Ethernet Switch

MU

IEC61850 Process Bus

IEC61850 Station Bus



6-64

All equipment installed in a substation should be connected to an earthing system effectively.

Resistance of the earthing system shall be designed based on IEEE 80.

2) Countermeasures for disasters

i) Dust Pollution

For substations constructed in areas affected by dust contamination, appropriate countermeasures

shall be taken into account in the design based on the level of pollution.

ii) Lightning

For the protection of substation equipment from lightning, appropriate measures shall be taken in

the design of the substation to achieve the required network reliability and site-specific conditions.

iii) Fire

Appropriate measures shall be taken to protect operators and equipment from fire or explosions

and, in the worst situations, to localize the fire to within a limited area.

iv) Earthquakes

The effect of earthquakes will be considered in the basic design of substations.

3) Considerations for environment

i) Noise

Include in the planning of a substation, which is to be newly constructed or expanded, necessary

measures to limit noise to within reasonable levels.

ii) Vibration

Include in the planning of a substation, which is to be constructed or expanded, necessary

measures to limit the vibration levels in the substation to within the country-recognized standard

values.

iii) Harmony with environment

For a substation that is to be constructed or expanded, special attention should be given to the

protection of the natural environment in the surrounding areas, and to the presentation of the living

environment, such as sunshine, scenery, radio interference, etc., as well as harmony with the regional

community.

Design Criteria

(1) Applicable Standards The design, materials, manufacture, testing, inspection and performance of all electrical and

electromechanical equipment shall comply with the latest revision of the International Electrotechnical

Commission Standards (IEC), as listed below:

IEC 60044-1 Instrument transformers – Part 1: Current transformers

IEC 60044-1 Instrument transformers – Part 5: Capacitor voltage transformers

IEC 60071 Insulation coordination

IEC 60076 Power transformers

IEC 60099-4 Surge arresters – Part 4: Metal-oxide surge arresters without gaps for a.c.

systems

IEC 60265-2 High-voltage switches – Part 2: High-voltage switches for rated voltage of

52 kV and above

IEC 60694 Common specifications for high-voltage switchgear and control gear

standards

IEC 61850 Communication network and systems in substations

IEC 62271-100 High-voltage switchgear and control gear – Part 100: High-voltage

alternative-current circuit breakers

IEC 62271-102 High-voltage switchgear and control gear – Part 102: Alternative-current

disconnectors and earthing switch

IEC 62271-203 High-voltage switchgear and control gear – Part 203: Gas-insulated metal

-enclosed switchgear for rated voltage above 52 kV

In cases where IEC standards are not applicable to the conditions, international standards such as

ANSI, ASTM, BS, JIS, JEC and JEM will be applied.

(2) Insulation Co-ordination Insulation co-ordination for the design of 500 kV, 230 kV, 66 kV and 33 kV equipment are as



6-65

follows:

(1) Nominal system voltage 500 kV 230 kV 66 kV 33 kV

(2) Rated voltage (Highest voltage) 525 kV 245 kV 69 kV 36 kV

(3) Rated frequency 50 Hz 50 Hz 50 Hz 50 Hz

(4) Insulation levels

Rated short-duration power

frequency withstand voltage

(r.m.s)

80 kV

Rated lightning impulse

withstand voltage (peak value)

1,550 kV 750 kV 350 kV 195 kV

Minimum clearance of phase-to-

earth

4,100 mm 2,100 mm 700 mm 400 mm

Standard clearance of phase-to-

earth

8,000 mm 2,600 mm 1,000 mm 500 mm

Minimum clearance of phase-to-

phase

5,400 mm 3,000 mm 1,100 mm 600 mm

Standard clearance of phase-to-

phase

8,000 mm 4,000 mm 1,500 mm 900 mm

Sar Ta Lin New 500 kV Substation

(1) Location and Current Situation As described in Chapter 2.6, Sar Ta Lin substation will be constructed at latitude 17° 03’ 50” north

and longitude 96° 17’ 28” east on the northern side of the YCDC area. The location map of the new

Sar Ta Lin 500 kV substation is referred to in Figure 2.6-1 and Figure 4.2-4.

Although the land acquisition will be conducted on the initiative of DPTSC, the current situation of

the land is a farm, as shown in the following pictures:


Figure 6.6-3 Photos of Planned Location for Construction of Sar Ta Lin Substation

(2) Scope of Work for the Project The JICA Study Team carried out a site survey and basic design for construction of the new 500 kV

substation considering future expansion and augmentation of the substation.

(3) Busbar Arrangement and Layout 1) Busbar Arrangement

Since the new Sar Ta Lin 500 kV substation will play a significant role in supplying power to

Yangon City, the configuration of the 500 kV switchgear, as a backbone facility, must be reliable.

Therefore, the JICA Survey Team adopted a one and a half circuit breaker arrangement, the same as

the Pharyargyii substation. As for 230 kV switchgear, a double busbar arrangement is adopted

considering expandability and reliability.

2） Layout

In order to avoid influence on surrounding residences, Sar Ta Lin Substation will be constructed



6-66

within land of approx. 530 m x 450 m, as shown in Annexure-6-4-2.

(4) Equipment Procurement and Quantities In this Project, 500 kV switchgear with eight bays of transmission line, three bays of main

transformer having a capacity of 500 MVA per each unit, two bays of 500 kV shunt reactors and 230

kV switchgears with eight bays of transmission lines, three bays of transformers and bus coupler bays

are to be installed in Sar Ta Lin new 500 kV substation. The drawings in Appendix 6-4-1 show the

basic design of new 500 kV substation.

- DWG No. MY-TLP3-NS-SLD_01 Single Line Diagram (Appendix 6-4-1)

1) 500 kV Substation Facility

i) Ten units, including spares for 500/230/33 kV, 166.7 MVA and single-phase main

transformer with on-load tap changer (OLTC)

ii) Two units of 500 kV shunt reactor, 100 MVar

iii) 500 kV switchgear in one and a half circuit breaker arrangement

The 500 kV switchgear in one and a half circuit breaker scheme includes eight (8) transmission

line bays and three (3) transformer bays

- 500 kV GCB 24 sets

- 500 kV DS/ES 60 sets

- 500 kV CT 60 sets

- 500 kV VT 13 sets

- 500 kV CVT 8 sets

- 420 kV SA 12 sets

- Line trap 16 sets

- 500 kV busbar 1 lot (One and a Half CB arrangement)

The associated gantry structures for the above system shall be supplied and installed.

The associated steel support structures and foundations for the above equipment with all

necessary connecting materials shall be supplied and installed.

The connection work between the dead-end towers, associated gantry structures and the

above equipment shall be carried out and all necessary materials for the work such as power

conductors, tension insulator sets, fittings, post insulators, connectors, accessories, power and

control cables, etc. shall be supplied and installed.

The above equipment shall be properly earthed with underground earthing mesh and all

necessary materials such as earthing conductors shall be supplied.

2) 230 kV Switchgear

i) 230 kV double busbar scheme switchgear

The 230 kV double busbar scheme includes eight (8) transmission line bays, three (3) transformer

bays and one (1) bus coupler bay.



- 230 kV DS 22 sets

- 230 kV CT 12 sets

- 230 kV CVT 13 sets

- 196 kV SA 11 sets

- Line trap 16 sets

- 230 kV busbar 1 lot (Double busbar scheme)










3) Installation of Control and Protection panels



6-67

Protection relay panel

- Main transformer protection relay panel 3 panels

- 500 kV shunt reactor protection relay panel 2 panels

- 500 kV transmission line protection relay panels 8 panels

- 500 kV busbar protection relay panels 2 panels


- 230 kV busbar protection relay panels 2 panels

Control panel

- Main transformer primary side control panel 3 panels

- Main transformer OLTC panels 3 panels

- 500 kV shunt reactor control panel 2 panels

- 500 kV transmission line control and synchronizing panel 8 panels


SCADA (SAS)

- Remote control and monitoring system 1 lot

The associated power and control cables with necessary accessories shall be supplied and

installed.

All necessary meters including ammeters, voltmeters and watt-hour meters, etc. shall be

supplied and installed.

SCADA system shall be designed with control, monitoring and measuring of 500 and 230 kV

switchyard, 500/230/33 kV main transformers, 500 kV shunt reactors and 33 kV switchgear

4) Installation of communication equipment

The following optical-fiber telecommunication equipment shall be supplied and installed.

- Optical distribution frame (ODF) for connection and 24 core optical fiber cable

- Patch cables connecting ODF with synchronous transport module -1 (STM-1) and

multiplexer

- Supply STM-1 and multiplexer with multi channels of not less than 2 Mbit/s interface.

- Optical fiber splicing boxes (i.e., for termination of OPGW on the steel gantry structure in

the substation)

5) Miscellaneous electrical equipment

- Indoor type 500 kVA auto start module type diesel generator set with associated

switchgear, power cables and fuel tank

- 400 V AC distribution switchboard equipped with double-throw breaker including

necessary cables and accessories

- 110 V DC system including two sets of 110 kV battery banks, two sets of chargers, and

one set of distribution boards

- 50 V DC system including two sets of 50 V batteries, two sets of chargers, and one set of

distribution board

- Earthing system covering the new substation area including earthing rods, conductors, etc.

- Overhead substation shield wire system including shield wires and supporting structures

for protection against lightning

- Outdoor substation lighting system

6) Civil and building work

The associated civil and building work for the above work shall be carried out as follows:

- Cleaning, cutting, filling, leveling and compacting of the new substation area

- Excavation and backfilling as required

- Gravelling of the complete additional substation area

- Construction of external security fences

- Construction of station service road

- Construction of gantries for 500 kV and 230 kV switchyards

- Construction of steel structures and equipment support

- Construction of concrete foundations for all equipment

- Construction of oil pit from main transformers and shunt reactors

- Construction of drainage pit and conduit

- Construction of cable pit



6-68

- Construction of a complete substation control building with control room, 33 kV cubicle

room, office, workshop, storage room, battery room, kitchen, toilet, etc.

- Construction of guard house for security personnel beside the main gate

- Supply and installation of air conditioning and ventilation equipment for the substation

building

- Supply and installation of water well and storage facility and wastewater and septic tank

facility

- Supply and installation of firefighting equipment associated with air conditioning system

for the control building

- All necessary materials for the above work such as concrete, aggregate, reinforcements,

accessories, etc. shall be supplied.

6) Other work

- Spare parts for at least 5 years of operation

- Tools and erection accessories as required

- Complete documentation for operation and maintenance

- Training for DPTSC staff at manufacturer’s factory and at site

(5) Specifications of Major Equipment 1) 500/230/33 kV Main transformer

i) Type

Single-phase, oil-immersed type, outdoor and ONAN/ONAF cooling type with on-load-tap

changing device, designed in accordance with IEC 60076 and 60289.

ii) Ratings Rated power 166.7 MVA (ONAN/ONAF)

Rated frequency 50 Hz

Rated voltage ratio 500/230/33 kV

Vector group notation YNa0d11

Short circuit impedance About 12.0 %

Rated insulation level HV LV

a) Rated short-duration power-frequency withstand voltage (r.m.s.

value) 750 kV 395 kV

b) Rated lightning impulse withstand voltage (peak value) 1,550 kV 750 kV

iii) On-load tap changing equipment (OLTC)

- Step: ±8 x 1.25 %

- Number of taps: 17 taps

2) 500 kV Shunt Reactor

i) Type

Three-phase, oil-immersed type, outdoor and ONAN cooling type shall be designed in accordance

with IEC 60076 and 60289.

ii) Ratings Rated voltage 500 kV

Rated 100 MVA


Rated insulation level at HV side (LI&PF)/current To be determined in Final Report

3) Gas Insulated Switchgear

i) Type

The GIS or H-GIS shall be metal-enclosed, three-phase busbar and switchgear type, for outdoor

use, and filled with SF6 insulation gas.

ii) Circuit breaker Rated voltage 500 kV

Rated main busbar normal current 6,000 A

Rated feeder normal current 2,500 A


Rated short-circuit breaking current 40 kA, 1 sec.

Rated interrupting time less than or equal to 3 cycle



6-69

Rated operating sequence O - 0.3 sec. - CO - 3 min. - CO

Rated closing operation voltage DC 110 V

Rated control voltage DC 110 V

Rated insulation level


value) 750 kV

b) Rated lightning impulse withstand voltage (peak value) 1,550 kV

The circuit breakers shall be suitable for single-pole tripping and rapid auto-reclosing, provided

with a motor-operated spring mechanism, and shall comply with the related IEC

standards/recommendations.

The circuit breakers shall be equipped with an operation mechanism for DC and the mechanism

shall ensure uniform and positive closing and opening.

iii) Disconnectors and earthing switches Rated voltage 500 kV

Rated normal current 2,500 A


Rated short-circuit withstand current 40 kA, 1 sec.

Rated control voltage DC 110 C



value) 750 kV


The disconnectors and earthing switch shall both be motor-operated and provided with a manual

operating mechanism.

Motor-operated disconnectors and earthing switch shall be designed with three-pole operation and

the motor shall be operated on DC auxiliary power.

iv) Current transformer Highest system voltage 525 kV




value) 750 kV


Rated current ratio

2,500-1,250 A : 1 A(TL and

busbar)

1,000A : 1A (SS)

Accuracy classes 5P20 for protection, Class 0.2 for

metering

v) Voltage transformer Highest system voltage 525 kV


Voltage ratio 500 𝑘𝑉

√3:110 𝑉

√3:110 𝑉

√3

Accuracy classes 3P+0.5



value) 750 kV


4) Air Insulated Switchgear

i) Circuit breaker

The 230 kV circuit breakers shall be SF6 gas type, with three-pole collective arrangement and for

outdoor use. The circuit breakers shall be suitable for single-pole tripping and rapid auto-reclosing,

provided with a motor-operated spring mechanism, and shall comply with the related IEC

standards/recommendations. Rated voltage 230 kV





6-70








value) 395 kV

b) Rated lightning impulse withstand voltage (peak value) 750 kV

The circuit breakers shall be equipped with an operation mechanism for DC power, motor

operated and with a manual handle and the mechanism shall ensure uniform and positive closing and

opening.

ii) Disconnectors and earthing switches

The 230 kV disconnectors shall be three-phase, two-column, rotary and center air break type with

horizontal operation. Earthing switches shall be triple-pole, single-throw, vertical single break and

manual three-phase group operation type.

The disconnectors and earthing switches shall be suitable for outdoor use. The earthing switches

shall be mounted on the disconnectors whenever necessary and where specified. Rated voltage 230 kV







value) 395 kV


The disconnectors shall be motor-operated and provided with a manual operating mechanism with

a hand crank. The earthing switch shall be provided with a manual operating mechanism.

Motor-operated disconnectors shall be designed with three-pole operation and the motor shall be

operated on DC power.

iii) Current transformer

The 230 kV current transformers shall be single-phase, porcelain-insulated, oil-immersed and air-

tight sealed post insulator type, for outdoor use and shall be designed in accordance with IEC 60044-

1. Highest system voltage 230 kV




value) 750 kV


Rated current ratio

4,000-2,000 A : 1 A(TL)

2,000-1,000 A : 1 A(TL)

4,000 A : 1 A (Busbar)

2,500-1,250 A : 1 A (SS)

1,000A : 1A (SS)


metering

iv) Capacitor Voltage transformer

The 500 and 230 kV voltage transformers shall be single-phase, capacitor type and shall be designed

in accordance with IEC 60044-5.

Highest system voltage 525 kV 245 kV



√3:110 𝑉

√3:110 𝑉

√3

230 𝑘𝑉

√3:110 𝑉

√3:110 𝑉

√3




6-71


a) Rated short-duration power-frequency withstand

voltage (r.m.s. value) 750 kV 395 kV

b) Rated lightning impulse withstand voltage (peak

value) 1,550 kV 750 kV

v) Surge Arresters

The 420 and 196 kV surge arresters shall be gapless, metal-oxide, outdoor and heavy duty type.

The arresters shall be designed in accordance with IEC 60099-4.

Rated voltage (r.m.s. value) 420 kV 196 kV


Nominal discharge current 10 kA 10 kA

Long-duration discharge class Class 3 (Table-5, IEC 60099-4)

Pressure-relief current 40 kA

Rated insulation levels for insulators

a) Rated short-duration power-frequency

withstand voltage (r.m.s. value) 750 kV 395 kV

b) Rated lightning impulse withstand voltage

(peak value) 1,550 kV 750 kV

East Dagon Substation

(1) Location and Current Situation 1) Location

As shown in the following figure, the East Dagon S/S is located at latitude 16° 57’ 02” north and

longitude 96° 16’ 43” east in the East Dagon Township of Yangon City.

Source: JICA Survey Team by using Google Earth

Figure 6.6-4 Location Map of East Dagon Substation

2) Current situation

The East Dagon substation has been operating since 2016 and consists of the following

equipment:

230 kV Gas insulated switchgear (Manufacturer: Hyundai)



6-72

Double busbar scheme

Two (2) transmission line bays to Thaketa substation and Thanlyin substation, one

circuit for each

Two (2) transformer bays

Bus coupler

Two (2) sets of 230/66/11 kV main transformers (Manufacturer: Hyundai)

Rated capacity: 125 MVA

OLTC: 17 taps

Cooling method: ONAF/ONAN

Impedance: 12.328 %

66 kV Gas insulated switchgear (Manufacturer: Hyundai)


Eight (8) transmission line bays

Two (2) transformer bays

Bus coupler

11 kV switchgear

Station service facilities


Figure 6.6-5 Photos of Current East Dagon Substation

The arrangement of control and protection panels for 230 and 66 kV switchgear in the control

room is shown in Figure 6.6-6 below. After examination, the JICA Survey Team confirmed that there

is enough space for installation of additional panels in the case of expansion of switchgear in the

Project.


Figure 6.6-6 Layout of Control Room in East Dagon Substation

6

5

4

3

2

1

12

11

10

9

8

7

18

17

16

15

14

13

20

19

21

24

23

22

11,800

8,53

0

800

800

800

800

800

800

800

800

800

800

800

800

830 830 830

800

800

800

600

600

600

800

800

1,02

0

2,000

2,63

0

2,63

0

Panel List:1. 230/66/11 kV Transformer No.2 Control & Protection Panel2. 230 kV Transmission Line No.2 (Tharketa) Control & Protection Panel 3. 230 kV Bus Coupler Control & Protection Panel4. 230 kV Transmission Line No.1 (Thanlyin) Control & Protection Panel5. 230/66/11 kV Transformer No.2 Control & Protection Panel6. 230 kV Busbar Differential Protection Panel

7. 66 kV Transmission Line Control & Protection Panel No.88. 66 kV Transmission Line Control & Protection Panel No.79. 66kV Transformer Control & Protection Panel No.210. 66 kV Transmission Line Control & Protection Panel No.611. 66 kV Transmission Line Control & Protection Panel No.512. 66kV Bus Coupler Control & Protection Panel13. 66 kV Transmission Line Control & Protection Panel No.414. 66 kV Transmission Line Control & Protection Panel No.315. 66kV Transformer Control & Protection Panel No.116. 66 kV Transmission Line Control & Protection Panel No.217. 66 kV Transmission Line Control & Protection Panel No.118. 66kV Busbar Differential Protection Panel

19. Remote Control Panel No.220. Remote Control Panel No.121. Under Frequency Protection Panel22. Central Processing Module23. East Dagon S/S Fault Recording System No.124. East Dagon S/S Fault Recording System No.2

:Available Space for Panel Installation in Phase 3



6-73

(2) Scope of Work for the Project In the Project, two (2) additional 230 kV transmission line bays in GIS shall be installed in order to

connect the 230 kV T/L to the new 500 kV substation. Therefore, the JICA Survey Team carried out a

basic design for the augmentation of the 230 kV transmission line bay.

(3) Busbar Arrangement and Layout i) Busbar arrangement

Double busbar scheme is applied to 230 kV GIS in East Dagon substation, as per the following

figure:


Figure 6.6-7 Single Line Diagram of 230 kV Switchgear in East Dagon Substation

Since there are no spare feeders in the existing 230 kV GIS, installation of two (2) additional feeders

of transmission line is required in the Project.

A single line diagram of 230 kV switchgear after the Project is shown below:

M

DS1,600A40kA

M

DS1,600A40kA

GCB 1,600A 40kA

800-400/1A 5P20, 30VA

800-400/1A 0.2FS5, 20VA

800-400/1A 5P20, 30VA

3,000-1,600/1A 5P20, 20VA

M

M

M

DS+ES3,150A, 40kA

M

GCB 3,150A 40kA

230/66/11 kV Transformer No.2125MVAYNyn0d11ONAF/ONAN

MDS+ES1,600A40kA

M

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

SA

M

DS1,600A40kA

M

DS1,600A40kA

GCB 1,600A 40kA

800-400/1A 5P20, 30VA

800-400/1A 0.2FS5, 20VA

800-400/1A 5P20, 30VA

3,000-1,600/1A 5P20, 20VA

M

M


MDS+ES1,600A40kA

M

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

SA

3,000-1,600/1A 5P20, 20VA

3,000-1,600/1A 5P20, 20VA

3,000-1,600/1A 5P20, 20VA

3,000-1,600/1A 0.2FS5, 20VA

M

DS+ES3,150A, 40kA

M

M M

GCB 1,600A 40kA

1,600-800/1A 5P20, 20VA

1,600-800/1A 0.2FS5, 20VA

1,600-800/1A 5P20, 20VA

3,000-1,600/1A 5P20, 20VA

M

DS+ES1,600A40kA

M

M

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

SA

230kV Tharkheta

M M

GCB 1,600A 40kA

M

DS+ES1,600A40kA

M

M

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

SA

230kV Thanlyin

1,600-800/1A 5P20, 20VA

1,600-800/1A 0.2FS5, 20VA

1,600-800/1A 5P20, 20VA

3,000-1,600/1A 5P20, 20VA

245kV BB1-A, 3,150A, 40kA

245kV BB2-A, 3,150A, 40kA

M

M

M

M

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

M

M

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

245kV BB1-B, 3,150A, 40kA

245kV BB2-B, 3,150A, 40kA



6-74


Figure 6.6-8 Single Line Diagram of 230 kV Switchgear in East Dagon Substation After the Project

2） Layout

There is unused space of approx. 30 m at the east side of the existing 230 kV GIS, as per the

following figure. This is sufficient to install four (4) additional GIS feeders including spares for the

Project.

M

DS1,600A40kA

M

DS1,600A40kA

GCB 1,600A 40kA

800-400/1A 5P20, 30VA

800-400/1A 0.2FS5, 20VA

800-400/1A 5P20, 30VA

3,000-1,600/1A 5P20, 20VA

M

M

M

DS+ES3,150A, 40kA

M

GCB 3,150A 40kA


MDS+ES1,600A40kA

M

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

SA

M

DS1,600A40kA

M

DS1,600A40kA

GCB 1,600A 40kA

800-400/1A 5P20, 30VA

800-400/1A 0.2FS5, 20VA

800-400/1A 5P20, 30VA

3,000-1,600/1A 5P20, 20VA

M

M


MDS+ES1,600A40kA

M

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

SA

3,000-1,600/1A 5P20, 20VA

3,000-1,600/1A 5P20, 20VA

3,000-1,600/1A 5P20, 20VA

3,000-1,600/1A 0.2FS5, 20VA

M

DS+ES3,150A, 40kA

M

M M

GCB 1,600A 40kA

1,600-800/1A 5P20, 20VA

1,600-800/1A 0.2FS5, 20VA

1,600-800/1A 5P20, 20VA

3,000-1,600/1A 5P20, 20VA

M

DS+ES1,600A40kA

M

M

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

SA

230kV Tharkheta

M M

GCB 1,600A 40kA

M

DS+ES1,600A40kA

M

M

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

SA

230kV Thanlyin

1,600-800/1A 5P20, 20VA

1,600-800/1A 0.2FS5, 20VA

1,600-800/1A 5P20, 20VA

3,000-1,600/1A 5P20, 20VA

245kV BB1-A, 3,150A, 40kA

245kV BB2-A, 3,150A, 40kA

M

M

M

M

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

M

M

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

245kV BB1-B, 3,150A, 40kA

245kV BB2-B, 3,150A, 40kA

GCB 1,600A 40kA

DS+ES1,600A40kA

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

SA

230kV Sar Ta Line SS (2)

1,600-800/1A 5P20, 20VA

1,600-800/1A 0.2FS5, 20VA

1,600-800/1A 5P20, 20VA

3,000-1,600/1A 5P20, 20VA

M

MM

M M

GCB 1,600A 40kA

DS+ES1,600A40kA

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

SA

230kV Sar Ta Lin SS (1)

1,600-800/1A 5P20, 20VA

1,600-800/1A 0.2FS5, 20VA

1,600-800/1A 5P20, 20VA

3,000-1,600/1A 5P20, 20VA

M

MM

M M

Scope of This Project

GCB 1,600A 40kA

DS+ES1,600A40kA

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

Spare

1,600-800/1A 5P20, 20VA

1,600-800/1A 0.2FS5, 20VA

1,600-800/1A 5P20, 20VA

3,000-1,600/1A 5P20, 20VA

M

MM

M M

GCB 1,600A 40kA

DS+ES1,600A40kA

VT 0.5P: 230kV/ 3S: 110V/ 3, 0.2, 30VAT: 110V/ 3, 3P, 30VA

Spare

1,600-800/1A 5P20, 20VA

1,600-800/1A 0.2FS5, 20VA

1,600-800/1A 5P20, 20VA

3,000-1,600/1A 5P20, 20VA

M

MM

M M

Expansion of 230 kV GIS

Existing 66kV TL

Existing 66kV TL

Existin

g 66kV

TL

230 kV Underground CableTo Existing 230 kV GIS

Gantry Structure for 230 kV TL

230 kV TL to Sar Ta Lin 500 kV SS – 2 cct

About 30 m



6-75


Figure 6.6-9 Layout of 230 kV Switchgear in East Dagon Substation

3） Method of Expansion for 230 kV GIS

When the 230 kV GIS is extended in the Project, it is desirable to connect additional bays to the

existing GIS via the optimum method in order to reduce the power outage time at the substation to the

minimum. The method of expansion obtained from the original manufacturer is attached in Appendix

6-4-6.

(4) Equipment Procurement and Quantities In this Project, two (2) additional bays are installed in the East Dagon substation. The drawings in

Appendix 6-4-3 show the basic design of East Dagon substation.

- DWG No. MY-TLP3-ED-SLD_02 Single Line Diagram (Appendix 6-4-3)

1) Expansion of 230 kV switchgear

i) 230 kV GIS transmission line bay

- 245 kV feeder 4 feeders

- GIS local control panel 4 panels

- Cable head (GIS) 2 sets

ii) 230 kV outdoor switchgear

- 245 kV CVT 6 sets

- Line trap 4 sets

- Cable head (AIS) 2 sets

- 196 kV SA 3 sets








6-76





iii) Extension of protection and control panels



Control panel


SCADA system

- Modification of existing SCADA system


installed.




Cleaning, cutting, filling, leveling and compacting around additional GIS and 230 kV T/L

terminal tower.

Excavation and backfilling as required

3) Other work





(5) Specifications of Major Equipment 1) Gas insulated switchgear

i) Type

The GIS shall be metal-enclosed, three-phase busbar and switchgear type, for outdoor use, and

filled with SF6 insulation gas.












value) 395 kV





The circuit breakers shall be equipped with an operation mechanism for DC power, motor

operated and with a manual handle and the mechanism shall ensure uniform and positive closing and

opening









6-77


value) 395 kV










value) 395 kV


Rated current ratio 3,000-1,600 A : 1 A

1,600-800 A : 1 A


metering




√3:110 𝑉

√3:110 𝑉

√3




value) 395 kV


2) Capacitor voltage transformer

i) Type

The 230 kV voltage transformers shall be single-phase, capacitor type and shall be designed in

accordance with IEC 60044-5.

ii) Ratings Highest system voltage 245 kV



√3:

110 𝑉

√3:110 𝑉

√3

Accuracy classes 3P, 0.2



voltage (r.m.s. value) 395 kV


value) 750 kV



6-78

3) 196 kV Surge Arrester

The 196 kV surge arresters shall be gapless, metal-oxide, outdoor and heavy duty type. The

arresters shall be designed in accordance with IEC 60099-4

Rated voltage (r.m.s. value) 196 kV


Nominal discharge current 10 kA





withstand voltage (r.m.s. value) 395 kV


(peak value) 750 kV

Hlawga Substation


As shown in the following figure, the Hlawga S/S is located at latitude 16° 58’ 54” north and

longitude 96° 07’ 35” east in the Mingaladon Township of Yangon City. Because the Hlawga

substation is surrounded by a national park and military reservation, it is required to expand and/or

augment the substation within the existing land.

Source: JICA Survey Team Editing Google Earth

Figure 6.6-10 Location Map of Hlawga Substation

2) Current situation

The Hlawga substation has been operating since 1960 and consists of the following equipment:

230 kV Air insulated switchgear

Single busbar scheme

Three (3) transmission line bays to Shwedaung substation, Tharyagone substation and

Thaketa substation

Four (4) transformer bays



6-79

Three (3) 230 kV Capacitor banks, 50 MVar x 2 and 20 MVar x 1

One (1) 230/66/11 kV main transformer


Three (3) 230/33/11 kV main transformer


66 kV switchgear


Three (3) transmission line feeders

One (1) transformer feeder

33 kV switchgear


Thirty (30) transmission line feeders

Six (6) transformer feeders

11 kV switchgear



Figure 6.6-11 Photos of Current Hlawga Substation

(2) Scope of Work for the Project In the Project, the existing 230 kV switchgear is upgraded to a GIS system, including expansion

for the connection of four (4) circuits to the new Sar Ta Lin 500 kV substation in order to secure the

reliability of equipment in future. In addition, the JICA Survey Team conducted the basic design in

consideration of future expansion since there are several plans to extend the 230 kV facilities.

In accordance with the discussion with DPTSC, the number of feeders in the GIS system

constructed via the Project will be 17, as below. In this connection, the transmission line feeder to

Tharyagone substation is not counted in the upgrade to GIS because the power flow of this line after

the Project will be low.

Transmission Line feeders 11 bays

To Sar Ta Lin substation 4 bays

To Thaketa substation 2 bays

To Wartayar substation 2 bays

To Shwedaung substation 1 bay

Spare 2 bays

Transformer feeders 4 bays 230/33/11 kV, 150 MVA transformer 3 bays

230/66/11 kV, 125 MVA transformer 1 bay

Bus coupler 2 bays

(3) Busbar Arrangement and Layout i) Busbar arrangement

A single busbar arrangement is applied to the 230 kV switchgear in Hlawga substation, as shown in

the following figure. Although 230 kV capacitor banks are installed for voltage control, it is assumed

that these capacitor banks were necessary when Hlawga substation started operation due to there not



6-80

being enough supply lines. Therefore, our design considered removing these capacitor banks because

it seems they will not be necessary for the Project’s implementation.

Source: DPTSC

Figure 6.6-12 Single Line Diagram of 230 kV Switchgear in Hlawga Substation

A single line diagram after the Project is shown below. Because Hlawga substation doesn’t have

enough space for the full installation of GIS with the required feeders above, we planned to conduct

the upgrading work step by step as below:

First step: Installation of GIS as far as possible in available space

Second step: Changing the connection of the 230kV transmission line feeders in AIS which

have been already prepared in GIS

Third step: Removal of the non-used 230 kV AIS and installation of remaining feeders of GIS

Fourth step: Changing the connection of remaining transmission feeder in AIS to GIS


Figure 6.6-13 Single Line Diagram of 230 kV Switchgear in Hlawga Substation after the Project

2） Layout

As shown in Figure 6.6-14, when considering the connection of transmission lines currently planned

to Wartayar substation with two circuits, East Dagon substation with one circuit and Thaketa

substation with one circuit, there is only space of approx. 27 m x 35 m on the southern side of the 230

kV switchgear. Therefore, installation of GIS shall be separated into two phases.

500-1000/1/1/1/1/1

A

GCB

1250 A

230 kV, 50 MVAR Cap Bank (1) 230 kV, 25 MVAR Cap Bank (2)

200-400/5/5/5 A

GCB 3150 A

200-400/5/5/5 A 350-700/5/5/5 A

GCB

1250 A

400-800/1/1/1 A

GCB

3150 AGCB 3150 A

230kV Shwedaung 230kV Tharyargone230 kV, 50 MVAR Cap Bank (3)

150-300/5/5/5 A

GCB 3150 A

Bus Section D/S

800A

GCB

1250 A

300-600/1/1/1/1/1 A

125 MVA

230/66/11 kV Bank

1000-2000/1/1/1/1/1 A

GCB

1600 A

250-500/5/5/5A

100 MVA

230/33/11 kV

Bank (1)

GCB 3150 A

GCB

2000 A

2000/5/5/5 A

250-500/5/5/5A

GCB 3150 A

100 MVA

230/33/11 kV

Bank (2)

GCB

2000 A

2000/5/5/5 A

( -162.0 MW)

(-7.4 MW)

(- 170.2 MW)

(- 0.2 MW)

(1304.0 A) (1260.0 A)

250-500/5/5/5 A

GCB

1250 A

100 MVA

230/33/11 kV

Bank (4)

GCB

2500 A

2000/5/5/5 A

(1117.0 A)

GCB

1250 A

200-400/1/ 1/

1A

GCB

1250 A

200-400/1/ 1/1A

GCB

1250 A

66/0.11kV

GCB 1250 A

200-400/1/1/1A

M

M

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

MM

M

M

M

SA

Spare

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Thaketa SS (1)

M

DS+ES

2,000A, 40kA

GCB

2,000A

40kA

2,000-1,000/1/1/1 A

M

DS+ES

2,000A, 40kA

M

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Thaketa SS (2)

MM

M

M

M

SA

230/33/11 kV, 150MVA

TR(1)

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Sar Ta Lin (2) Sar Ta Lin (1)

M

M

DS

2,000A, 40kA

DS

2,000A, 40kAMM

M

M

M

SA

230/33/11 kV, 150MVA

TR(2)

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Sar Ta Lin (3)

MM

DS+ES

2,000A, 40kA

GCB

2,000A

40kA

2,000-1,000/1/1/1 A

M

DS+ES

2,000A, 40kA

MM

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Sar Ta Lin (4)

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Wartayar (1)

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Wartayar (2)

MM

M

M

M

SA

230/66/11 kV,

125MVA

TR(3)

MM

M

M

M

SA

230/33/11 kV, 150MVA

TR(4)

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Shwedaung

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Spare

M

M

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

245kV BB1-A, 3,150A, 40kA

245kV BB2-A, 3,150A, 40kA

245kV BB1-B, 3,150A, 40kA

245kV BB2-B, 3,150A, 40kA

New 230 kV GIS (2nd

Phase)

New 230 kV GIS (1st Phase)



6-81

Source: JICA Survey Team from DPTSC Drawing

Figure 6.6-14 Layout of 230 kV Switchgear in Hlawga Substation Before the Project

Source: JICA Survey Team from DPTSC Drawing

Figure 6.6-15 Layout of 230 kV Switchgear in Hlawga Substation After the Project

The available space after connection of the current planned transmission lines as mentioned above

will be approximately 27 m x 35 m. The JICA Survey Team judged that a 230 kV GIS with a double

busbar scheme having six feeders, which requires 15.5 m x 7.4 m dimensions, can be installed in that

available space.



6-82


Figure 6.6-16 Necessary Dimensions of 230 kV GIS with Double Busbar (Reference)


Figure 6.6-17 Single Line Diagram of GIS in Hlawga Substation after 1st Phase

(4) Equipment Procurement and Quantities In this Project, 230 kV GIS is installed in the Hlawga substation as an upgrade, instead of the

existing AIS. The drawings in Appendix 6-4-5 and 6-4-6 show the basic design of Hlawga

substation.

- DWG No. MY-TLP3-HG-SLD_02 Single Line Diagram (Appendix 6-4-5)

- DWG No. MY-TLP3-HG-LYT_01 Layout Drawing (Appendix 6-4-6)

1) Installation of 230 kV switchgear

i) 230 kV GIS of double busbar scheme

M

M

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

MM

M

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Thaketa SS (1)

M

DS+ES

2,000A, 40kA

GCB

2,000A

40kA

2,000-1,000/1/1/1 A

M

DS+ES

2,000A, 40kA

M

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Thaketa SS (2)

MM

M

M

M

SA

230/33/11 kV, 150MVA

TR(1)

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA


M

245kV BB1-A, 3,150A, 40kA

245kV BB2-A, 3,150A, 40kA

Existing 230 kV Busbar

DS

(Existing)


M

M

DS

2,000A, 40kA



6-83

The 230 kV GIS with double busbar scheme includes eleven (11) transmission line bays, four (4)

transformer bays and two (2) bays for bus coupler.



- 230 kV DS 30 sets

- 230 kV CT 19 sets

- 500 kV VT 19 sets

- 196 kV SA 11 sets

Connection with the existing busbar




The connection work between the existing equipment, underground transmission lines and

the above equipment shall be carried out and all necessary materials for the work such as

cable head, connectors, accessories, power and control cables, etc. shall be supplied and

installed.



iii) Extension of protection and control panels



- 230 kV transformer feeder protection relay panels 4 panels

- 230 kV busbar coupler protection relay panels 2 panels

- 230 kV GIS busbar protection relay panels 2 panels

Control panel


- 230 kV busbar connection control and synchronizing panel 2 panels

SCADA System



installed.




Cleaning, cutting, filling, leveling and compacting around new GIS

Excavation and backfilling as required

3) Other work





- Partial removal of existing AIS



6-84

(5) Specifications of Major Equipment 1) Gas insulated switchgear

i) Type

The GIS shall be metal-enclosed, three-phase busbar and switchgear type, for outdoor use, and

filled with SF6 insulation gas.












value) 395 kV





The circuit breakers shall be equipped with an operation mechanism for DC and the mechanism

shall ensure uniform and positive closing and opening.








value) 395 kV










value) 395 kV


Rated current ratio

2,000-1,000 A : 1 A (busbar)

1,600-800 A : 1 A (TL and

busbar connection)


metering



6-85




√3:110 𝑉

√3:110 𝑉

√3




value) 395 kV


2) 196kV Surge arrester


arresters shall be designed in accordance with IEC 60099-4

Rated voltage (r.m.s. value) 196 kV







withstand voltage (r.m.s. value) 395 kV


(peak value) 750 kV

Thaketa Substation


As shown in the following figure, the Thaketa S/S is located at latitude 16° 48’ 42” north and

longitude 96° 13’ 33” east in the Thaketa Township of Yangon City.

Source: JICA Survey Team Editing Google Earth

Figure 6.6-18 Location Map of Hlawga Substation



6-86

2) Current Situation

Thaketa substation, including 230 kV equipment, is upgraded under ‘Urgent Rehabilitation and

Upgrade Project Phase 1 (hereinafter referred to as “MY-P2 Project”)’ with a Japanese ODA Loan.

Facility configuration after rehabilitation and upgrade in MY-P2 will be as follows:

230 kV Air insulated switchgear


Two (2) transmission line bays to Hlawga substation and Thanlyin substation

Four (4) transformer bays

Two (2) 230/66/11 kV main transformers


Two (2) 230/33/11 kV main transformers


66 kV switchgear


Nineteen (19) transmission line feeders

Two (2) transformer feeders

Two (2) bus couplers

33 kV switchgear


Thirteen (13) transmission line feeders

two (2) transformer feeders

One (1) bus coupler

11 kV switchgear



Figure 6.6-19 Photos of Current Hlawga Substation

(2) Scope of Work for the Project In the Project, one bay of 230 kV switchgear including line protection panel in Thaketa substation

is added, corresponding to augmentation of the existing 230 kV transmission line from one circuit to

two circuits. Replacement of existing 230 kV switchgear for the transmission line feeder to Hlawga

substation is not considered in the Project because this equipment will be rehabilitated in the MY-P2

Project.

(3) Busbar Arrangement and Layout 1) Busbar arrangement

The busbar arrangement of 230 kV AIS in Thaketa substation will be a single busbar arrangement,

the same as the existing configuration, even after the Project.



6-87

Source: MY-P2 Project

Figure 6.6-20 Single Line Diagram of 230 kV Switchgear in Thaketa Substation Before the Project

The single line diagram of 230 kV switchgear after the Project is shown in the following figure. The

space for additional 230 kV switchgear to be installed in the Project can be secured on the west side

of the existing transmission line bay to Hlawga substation.


Figure 6.6-21 Single Line Diagram of 230 kV Switchgear in Thaketa Substation After the Project

2） Layout

As stated above, the additional 230 kV transmission line bay to Hlawga substation will be installed

on the west side of the rehabilitated transmission line bay.

LA10kA

Hlawga (Additional)

ES DS2000A

500-1000/1/1/1ACTGCB

2000ADS

2000A

LTCVT



6-88

Source: MY-P2 Project

Figure 6.6-22 Layout of 230 kV Switchgear in Thaketa Substation After the Project

(4) Equipment Procurement and Quantities In the Project, one (1) additional 230 kV transmission line bay is installed in Thaketa substation.

The drawing in Appendix-6-4-7 shows the basic design of Thaketa substation.

- DWG No. MY-TLP3-TK-SLD_02 Single Line Diagram (Appendix 6-4-7)

1) Expansion of 230 kV switchgear

i) 230 kV switchgear of single busbar arrangement

- 230 kV GCB 1 set

- 230 kV DS/ES 1 set

- 230 kV DS 1 set

- 230 kV CT 1 set

- 230 kV CVT 1 set

- 196 kV SA 1 set

- Line trap 2 sets










ii) Expansion of Control and Protection panel


- 230 kV transmission line protection relay panels 1 panel

Control panel

- 230 kV transmission line control and synchronizing panel 1 panel

SCADA system


DPTSC agreed that this space is usedfor construction of 230kV T/L bayfor additional circuit to HlawgaSubstation

Hlawga SS (2)Hlawga SS (1)

66kV T/L

Thanlyn SSEast Dagon SS



6-89


installed.




- Cleaning, cutting, filling, leveling and compacting around additional 230 kV

switchgear

- Excavation and backfilling as required

3) Other work




(5) Specifications of Major Equipment 1) Air Insulated Switchgear

i) Circuit Breaker

The 230 kV circuit breakers shall be SF6 gas type, with a three-pole collective arrangement and

for outdoor use. The circuit breakers shall be suitable for single-pole tripping and rapid auto-

reclosing, provided with a motor-operated spring mechanism, and shall comply with the related IEC


Rated voltage 230 kV










value) 395 kV


The circuit breakers shall be equipped with an operation mechanism for DC power motor operated

and manual handle, and the mechanism shall ensure uniform and positive closing and opening.

ii) Disconnectors and earthing switches

The 230 kV disconnectors shall be three-phase, two-column, rotary and center air break type with

horizontal operation. Earthing switches shall be triple-pole, single-throw, vertical single break and

manual three-phase group operation type.

The disconnectors and earthing switches shall be suitable for outdoor use. The earthing switches

shall be mounted on the disconnectors whenever necessary and where specified. Rated voltage 230 kV







value) 395 kV


The disconnectors shall be motor-operated and provided with a manual operating mechanism with

a hand crank. The earthing switch shall be provided with a manual operating mechanism.

Motor-operated disconnectors shall be designed with three-pole operation and the motor shall be

operated on DC power.

iii) Current transformer



6-90

The 230 kV current transformers shall be single-phase, porcelain-insulated, oil-immersed and air-

tight sealed post insulator type, for outdoor use and shall be designed in accordance with IEC 60044-

1. Highest system voltage 230 kV




value) 750 kV


Rated current ratio 500-1,000A : 1/1/1A）


metering

iv) Capacitor Voltage transformer

The 500 and 230 kV voltage transformers shall be single-phase, capacitor type and shall be designed

in accordance with IEC 60044-5. Highest system voltage 245 kV



√3:110 𝑉

√3:110 𝑉

√3






value) 750 kV

v) 196 kV Surge Arresters


arresters shall be designed in accordance with IEC 60099-4. Rated voltage (r.m.s. value) 196 kV









value) 750 kV

6.7. Work and Procurement Plan

Work Plan

(1) Procedure for Changing-over to GIS in Hlawga Substation As stated above, it is necessary to install GIS in 2 phases due to the limited current space for

upgrading the existing 230 kV switchgear to GIS in Hlawga substation. In addition, since Hlawga

substation plays an important role in supplying power to Yangon City, the changing-over work to GIS

shall be conducted maintaining the operation of existing transmission lines as much as possible.

Therefore, the JICA Survey Team proposes to change over to GIS in four (4) steps, as described below:

1) Step-1: Installation of GIS (1st Phase) in available space

In Step-1, GIS with six (6) line feeders, of which one is for connection with the existing busbar,

and one bus coupler shall be installed in the available space of approximately 27 m x 32 m.

The details of GIS feeders to be installed in Step-1 are as below:

Transmission line feeder

To Sar Ta Lin substation x 2

To Thaketa substation including additional circuit x 2

Transformer feeder

230/33/11 kV 150 MVA main transformer x 1

Bus connection feeder to existing busbar x 1



6-91

Bus coupler for GIS in Step-1

In Step-1, the JICA Survey Team also recommends constructing the cable trench in advance of the

next step to lay the cable connecting from GIS to transformer, because the GIS in Hlawga substation

is designed to connect by cable from GIS to each piece of equipment like transformers and

overhead/underground transmission lines.


Figure 6.7-1 Layout of 230 kV Switchgear in Hlawga Substation (Step-1)


Figure 6.7-2 Single Line Diagram of 230 kV GIS in Hlawga Substation (Step-1)

2) Step 2: Changing the connection from GIS in Step-1 to Related Equipment

In Step-2, the connection between GIS installed in Step-1 and related equipment shall be conducted.

All transmission line feeders in GIS installed in Step-1 are connected by cables to Hlawga substation

from underground transmission lines. For transformers, it is recommended to install the cable head

230 kV GIS by 7 feeders includingbus coupler bay is installed incurrent available space.

New cable trench for 230kVpower cables shall be installedprior to Step-2.

Installation of Cable HeadBushing at the existing CVTposition

M

M

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

MM

M

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

M

DS+ES

2,000A, 40kA

GCB

2,000A

40kA

2,000-1,000/1/1/1 A

M

DS+ES

2,000A, 40kA

M

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

MM

M

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

M

245kV BB1-A, 3,150A, 40kA

245kV BB2-A, 3,150A, 40kA


M

M

DS

2,000A, 40kA



6-92

with bushing at the position of existing surge arresters and to connect the circuit from underground

cables to overhead conductors.

Furthermore, for the connection with the existing busbar, it is also recommended to install the cable

head with bushing in from of disconnectors, currently for CVT, and to connect with the existing busbar

for synchronization with the existing 230 kV system.

After all changing-over has been completed, non-used existing AIS connected to Thaketa substation

and Tharyagone substation shall be removed.



Connecting power cables fortransmission lines from 230kV GISthough cable trench

Connecting power cables forbusbar and TR (1) from 230kVGIS though cable trench

Remove of existing AIS switchgearafter connection the power cablefrom 230kV

Installation of Cable HeadBushing at surge arresterposition



6-93



3) Step-3: Installation of remaining GIS in 2nd Phase

In Step-3, GIS with nine (9) feeder bays and one (1) bus coupler bay shall be installed at the location

where the existing AIS was removed in Step-2.

The details of GIS feeders to be installed in Step-3 are as below:

Transmission line feeder

To Sar Ta Lin substation x 2

To Wartayar substation x 2

Spare x 1

Transformer feeder



Bus coupler for GIS in Step-1

In Step-3, the JICA Survey Team recommends constructing the cable trench in advance of the next

step to lay the cable connecting from GIS to the existing overhead transmission lines, to Watayar

substation and Shwedaung substation.

M

M

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

MM

M

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Thaketa SS (1)

M

DS+ES

2,000A, 40kA

GCB

2,000A

40kA

2,000-1,000/1/1/1 A

M

DS+ES

2,000A, 40kA

M

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Thaketa SS (2)

MM

M

M

M

SA

230/33/11 kV, 150MVA

TR(1)

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA


M

245kV BB1-A, 3,150A, 40kA

245kV BB2-A, 3,150A, 40kA


DS

(Existing)


M

M

DS

2,000A, 40kA



6-94





4) Step-4: Changing the connection from GIS in Step-3 to Related Equipment

In Step-4, the connection between the GIS installed in Step-3 and related equipment shall be

conducted. For transformers, it is recommended to install the cable head with bushing at the position

of the existing surge arresters and to connect the circuit from underground cables to overhead

conductors, the same as Step-2.

For connection to overhead transmission lines, it is also recommended to install the cable head with

bushing at the position of existing surge arresters and to connect with overhead transmission lines

from the cable trench.

After all changing-over has been completed, non-used existing AIS shall be removed. Then, the

upgrade to GIS will be completed.

Expansion of 230kV GIS in AIS spaceafter removal

New cable trench for 230kVpower cables shall be installedprior to Step-4.

M

M

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

MM

M

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Thaketa SS (1)

M

DS+ES

2,000A, 40kA

GCB

2,000A

40kA

2,000-1,000/1/1/1 A

M

DS+ES

2,000A, 40kA

M

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Thaketa SS (2)

MM

M

M

M

SA

230/33/11 kV, 150MVA

TR(1)

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA


M

M

DS

2,000A, 40kA

DS

2,000A, 40kAMM

M

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Sar Ta Lin (3)

MM

DS+ES

2,000A, 40kA

GCB

2,000A

40kA

2,000-1,000/1/1/1 A

M

DS+ES

2,000A, 40kA

MM

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Sar Ta Lin (4)

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

MM

M

M

M

SA

MM

M

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Spare

M

M

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

245kV BB1-A, 3,150A, 40kA

245kV BB2-A, 3,150A, 40kA

245kV BB1-B, 3,150A, 40kA

245kV BB2-B, 3,150A, 40kA

New 230 kV GIS (2nd

Phase)


DS

(Existing)




6-95





Connecting power cables fortransmission lines from 230kV GISthough cable trench

Connecting power cables forbusbar and TR (2) to (4) from230kV GIS though cable trench

Removal of existing AISswitchgear after connection ofthe power cable from 230kV GIS

Installation of Cable HeadBushing at surge arresterposition

M

M

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

MM

M

M

M

SA

Spare

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Thaketa SS (1)

M

DS+ES

2,000A, 40kA

GCB

2,000A

40kA

2,000-1,000/1/1/1 A

M

DS+ES

2,000A, 40kA

M

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Thaketa SS (2)

MM

M

M

M

SA

230/33/11 kV, 150MVA

TR(1)

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA


M

M

DS

2,000A, 40kA

DS

2,000A, 40kAMM

M

M

M

SA

230/33/11 kV, 150MVA

TR(2)

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Sar Ta Lin (3)

MM

DS+ES

2,000A, 40kA

GCB

2,000A

40kA

2,000-1,000/1/1/1 A

M

DS+ES

2,000A, 40kA

MM

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Sar Ta Lin (4)

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Wartayar (1)

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Wartayar (2)

MM

M

M

M

SA

230/66/11 kV,

125MVA

TR(3)

MM

M

M

M

SA

230/33/11 kV, 150MVA

TR(4)

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Shwedaung

M M

GCB

1,250A

40kA

M

DS+ES

1,250A

40kA

M

M

SA

Spare

M

M

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

VT 0.5

P: 230kV/ 3

S: 110V/ 3, 0.2, 30VA

T: 110V/ 3, 3P, 30VA

245kV BB1-A, 3,150A, 40kA

245kV BB2-A, 3,150A, 40kA

245kV BB1-B, 3,150A, 40kA

245kV BB2-B, 3,150A, 40kA

New 230 kV GIS (2nd

Phase)




7-1

7. Project Implementation Policy

7.1. Safety of Construction Work Substation work under the Project includes extension of three existing substations. As most of the

field work will be carried out under live conditions or tentative de-energized conditions at the existing

facilities in the substations, the contractors for the Project should proceed carefully and always work

paying full attention to the possibility of workers’ accidents, damage to the existing facilities,

unscheduled system supply interruptions, etc. Transmission line work over a long distance will cover

various kinds of operations, such as on high towers, in deep foundation excavated pits, with special

stringing tools, or frequent travelling on major roads/small village roads, etc. There are many

opportunities for fatal accidents and damage to public facilities. It has been observed that local workers

take little care in such construction work, working without any safety tools to protect themselves. To

prevent unexpected accidents, terms for the safety work should be specified in the contract documents.

7.2. COVID-19 Infection Prevention Measures It may be necessary to take the following measures during the construction period to prevent

COVID-19 infections.

- Wearing a mask.

- Face shields.

- Daily physical condition and hygiene management (habitual actions such as checking body

temperature, checking physical condition, hand washing, and frequent disinfection).

- If someone is not feeling well, ask him/her to leave the work area and take a rest or PCR test if

necessary.

- Maintain distance between each worker whenever possible.

- Temperature checks and alcohol disinfection by guards at the guard gates of new substation

construction sites and consulting offices (temperature checks and disinfection will have to be

conducted several times, each time the workers move).

- Reduction of meetings for all workers (limiting the number of people in meetings and

communicating information through instructions from the work manager).

- Separate work areas and the creation of a process schedule that avoids the proximity of each work

area (limit the number of workers in the substation building and allocate them to outdoor work, etc.).

- Installation of air cleaners in the field office.

- Limit the number of people moving vehicles.

Depending on the situation regarding the spread of infections, station a doctor at the construction

site and conduct PCR testing at the site.

7.3. Contract Management In terms of contract management considering the particular conditions in the Project, the items to

be taken into consideration are as below:

(1) Force Majeure (referring to GC G.37 in “Plant”) As represented by the recent spread of COVID-19 infections, there are cases in which the contractor

is forced to suspend work due to force majeure even in an ODA project. Although there are concerns

that such suspension will have a significant impact on the completion time of the planned project, if

the Employer (DPTSC in this case) forcibly demands that the contractor accelerate the construction

work when the construction is resumed, it is necessary to have a common understanding that the

project should be completed securing safety management and quality assurance, and allow an

extension to the construction period as necessary.

(2) Extension of Time for Completion (referring to GC H.40 in “Plant”) When the contract package is divided between transmission line and substation as in this project,



7-2

there is a concern that a delay in either one will affect the completion time of the other. At such time,

it will be necessary to consider extending the construction period as needed, but it is necessary to sort

out in advance who is responsible for such delay and the period of influence for each area of work.

Therefore, it is important to coordinate the processes and work between each package during

implementation of the Project.

(3) Contractor’s Claim of Time for Completion (referring to GC I.44 in “Plant”) In the transmission line construction project, land negotiation and land acquisition will be carried

out by the Employer. In this case, it is assumed that the land acquisition process will run into trouble

during the construction of the transmission line, and the construction work will have to be interrupted.

In the past, there was a case whereby the Employer was reluctant to charge the costs during the waiting

period of the contractor. On the other hand, there was also a case whereby the contractors, who were

unfamiliar with the contracts, did not charge for the costs themselves. Therefore, it is considered

necessary to properly raise issues in order to carry out the project in a way that the contractor will not

be disadvantaged.

7.4. Anti-graft Plan In order to realize transparent procurement in PQ and bidding, it is necessary to clarify the

evaluation criteria on the premise that a quantitative evaluation is performed at each evaluation with

consultant support. In addition, if any unnatural corrections are made to the bid evaluation report

prepared and supported by the consultant, the consultant should discuss and confirm the content with

the Employer, and consider discussing with JICA, if necessary.

In order to carry out transparent procurement procedures, it is recommended to comply with

transparent international standards such as the JICA guidelines. The JICA guidelines "Chapter 2:

Guidelines for Procurement under Japanese ODA Loans, Section 1.06 Corrupt or Fraudulent

Practices" are quoted below.

Source: JICA

7.5. Actions concerning Gender Necessary actions concerning gender to be proposed in each phase of the implementation stage in

this project are as below:



7-3

(1) Before Construction Construction of the access road for work considering easy access for daily activities (drinking

water, washing and farming etc.)

(2) Construction Period Equal work and pay

Employment promotion for women who want to work in cooking and material carrying work

Preparation of toilets, shower rooms and bedrooms by gender at accommodation and site

Arrangement of female supervisor at the site for female workers

Technical transfer of maintenance work for female staff in new substation

(3) After Construction Indirect improvement of the lives of women and children and their safety due to stable power

supply by strengthening the power grid



8-1

8. Project Implementation System

8.1. Suggestions for Configuring the Project Implementation and Operation and Maintenance Systems

Confirmation of Project Implementation System The MOEE organizational chart is shown in Figure 8.1-1. The Execution Agency (E/A) for the

Project will be assigned to DPTSC, which is in charge of the construction of transmission and

substation facilities above 132 kV, as per Phase 1 and Phase 2.

Source: MOEE

Figure 8.1-1 Organizational Chart of MOEE

There are three departments in DPTSC, the management department, Power Transmission Projects

Department (PTP) and Power System Department (PSD). Of these, PTP prepares the bidding

documents and manages the project during construction. Figure 8.1-2 shows the organization of

DPTSC.

Source: MOEE Figure 8.1-2 Organizational Chart of DPTSC

Capabilities of Each Department Related to the Project and its Role in the Project

The capabilities and roles of each department shown in Figure 8.1-2 are described below.

(1) Management Department 1) Financial Department

Management of budget and allocation to PTP

Reporting to Ministry of Planning and Finance (MOPE)

Confirmation of payment conditions

2) Material Planning Department (Yangon and Nay Pyi Taw)

Work for Custom Duties during Loading at port

Storage of materials

Director General

Deputy Director General



Administration Department

Finance Department

Material Planning

Department

Power Transmission Projects Department

(PTP)

Power Transmission Projects (Southern)

Office

Power Transmission Projects (Northern)

Office

Power System Department

(PSD)

Primary Substation

Projects

Transmission Line



8-2

Confirmation of quantity of materials

(2) Power Transmission Projects Department (PTP) 1) Project Implementation Branch

Planning for fuel supply and construction materials for transmission line and substation

projects

Evaluation of cost estimations for transmission line and substation projects

2) Design and Planning Branch

Preparation of design, BOQ and specifications and quality management

Preparation of bidding documents

Materials inspections

Technical and price evaluation for bidding

System analysis

3) Civil Branch

Management of civil work in transmission line and substation projects

Reporting on work progress

Inspection of civil work in each project

4) Power Transmission Projects (Southern) Office

Site management for transmission line and substation projects

Management of quality and performance

Coordination with region for land acquisition and reserved forest areas in project

Reporting to MORR on environmental and social impacts

(3) Power System Department (PSD) 1) Transmission Line Branch

Operation and maintenance for 230/132/66/33 kV transmission lines

Procurement of necessary materials for operation and maintenance

2) Primary Substation Branch

Operation and maintenance of 230 kV and 132 kV primary substations

Procurement of necessary materials for operation and maintenance

Execution Department for each Component Based on the capabilities and roles of each department mentioned in Chapter 10.2.2, the execution

department for the Project is shown in Table 8.1-1.

Table 8.1-1 Execution Department for each Component in the Project

Department Management PTP PSD

Branch Financial Material PIB Design Civil PTPO T/L S/S

Design X X

Bidding

Documents

X X X

Bidding

Evaluation

X

Contract

Negotiation

X X

Drawing

Approval

X X

Installation and

Work

Management

X X X X X

Individual

Inspection

X X

Commissioning

Test

X

O&M X X Source: JICA Survey Team



8-3

Organizational Structure of Executing Agency and main related Organizations (Organizational Chart)

The organizational chart of the “Power System Department”, which maintains and manages the

transmission and substation facilities, including the numbers of standard personnel, is shown below.

Figure 8.1-3 Organizational Chart of Power System Department

Table 8.1-2 Standard Numbers of Personnel for each Organization

Number of

personnel Remarks

System Planning (NPT) 57

National Control Center (NPT) 68

Load Dispatch Center (YGN) 68

SCADA and communications (NPT) 60

Substation (NPT) 20

System Protection and Testing (NPT) 45

System Protection and Testing (YGN) 45

Mobile Team (NPT) 58

Primary Substation 2,829 41 x 69 substations

Transmission Line (NPT) 20

Line Office (each regional) 2,055 137 x 15 offices

Total (Standard) 5,325

Total (Real) 3,994 5,325 x 75%

The actual working number of personnel is about 75% of the standard number, and the total number

of working personnel who operate, maintain and manage the transmission and substation facilities is

about 4,000. The standard number of personnel at the 500kV substation is assumed to be 67.

<O&M in substations> All substations above 132kV are manned, and the standard number of personnel in each substation

is 41 people. Since a new 500kV substation will be constructed in this project, it will be necessary to

increase the number of new substation personnel by 67 people x 75%. In addition, in order to carry

National Control Center (NPT)

(Director) 68

System Planning (NPT)

(Director) 57

Load Dispatch Center (YGN)

(Director) 68

Substation (NPT) (Director)

20

Transmission Line (NPT)

(Director) 20

SCADA and communications (NPT), (Director)

60

Primary Substation

Substation head: AD

41/substation

Mobile Team (NPT)

Section head: DD

58

System Protection and Testing

(YGN) Section head: DD

45

System Protection and Testing

(NPT) Section head: DD

45

Line Office (each regional) Office head: AD

137/office Total: 15 offices

Power System Department (DDG)

(Operation and Maintenance)

Admin/Finance/Materials Planning

(DDG)

Power Transmission Project (DDG)

(Design and Implementation)

Department of Power Transmission and System Control (DG)



8-4

out expansion work at three substations, it is considered necessary to increase the number of personnel

at each substation by about two.

<O&M for transmission facilities> The transmission line maintenance area is divided into 15 regions, as shown below, and transmission

maintenance offices in each region carry out the maintenance. The standard number of personnel at

each transmission line maintenance office is 137. New transmission lines will be constructed via this

Project, but all lines are within the maintenance area of the Kamarnat Transmission Line Maintenance

Office (the office outlined in red). For this reason, it is considered necessary to increase the number of

new personnel for transmission line O&M by 34, equivalent to 25% of the standard 137 personnel at

Kamarnat Transmission Line Maintenance Office.

Figure 8.1-4 Each Transmission Line Maintenance Office’s Area of Operations

The organization involved in the construction for this project is the “Power Transmission Project”.

The organizational chart of the “Power Transmission Project” is shown below.



8-5

Figure 8.1-5 Organizational Chart of Power Transmission Project

Project Implementation Unit (PMU) The following is a description of the project implementation structure for this project (Phase III)

with reference to the structure of the currently operating project (Phase I). In Phase I, there were two

substations, Meikhtila Substation and Taungoo Substation, and the Deputy Project Manager managed

each substation. In Phase III, the project will be divided into substation and transmission lines

according to the package. Since this project also includes the upgrade and expansion of 230kV, it is

further divided into 500kV and 230kV. The underground transmission lines will be included in the 230

kV transmission section. The draft structure table is shown below.

Project Director Office (Northern) Naypyitaw, (Director)

45

Project Planning & Design Branch Naypyitaw, (Director)

35 (DDG)

Power Transmission Project (Civil) Branch

Naypyitaw, (Director) 25

Project Implementation Branch Naypyitaw, (Director)

30

Power Transmission Project (Deputy Director General)

Project Director Office (Southern) Naypyitaw, (Director)

45

PM Office (Civil), (Northern) Naypyitaw, (Deputy Director)

60

PM Office (Civil), (Southern) Naypyitaw, (Deputy Director)

60

PM Office (1), Shwesaryan (Deputy Director)

120

PM Office (2), Meiktila (Deputy Director)

120

PM Office (3), Mandalay (Deputy Director)

120

PM Office (1), Yangon (Deputy Director)

120

PM Office (2), Tharyargone (Deputy Director)

120

PM Office (3), Shwe Taung (Deputy Director)

120



8-6

Organization Chart of Project Management Unit (PMU) for National Power

Transmission Network Development Project Phase III (DRAFT)

Figure 8.1-6 Phase III Implementation Structure (PMU) (Draft)

Project Director {Deputy Director General of

Power Transmission Project Department (PTPD), DPTSC}

Deputy Project Director {Director of

PTPD}

Deputy Project Director

{Director of PTPD}

Deputy Project Director {Director of

PTPD}

Project Planning

Department (Dept.)

Civil Dept.

Project Manager {Deputy Director}

Deputy Project

Manager {Assistant Director}

Project Manager {Deputy Director}

Deputy Project

Manager 1 {Assistant Director}

Deputy Project

Manager 2 {Assistant Director}

Director General of DPTSC

Director Material Planning

Dept.

Director Finance

Dept.

Procurement Finance


{Director of PTPD}


{Director of PTPD}

Project Manager

{Deputy Director}

Deputy Project


Assistant Director

Project Manager

{Deputy Director}

Deputy Project


Assistant Director

Project Manager

{Deputy Director}

Deputy Project


Assistant Director

Project Manager

{Deputy Director}

Deputy Project


Assistant Director

Project Implementation

Dept.

In charge of Substations (SS)

In charge of Transmission Lines (TL)

In charge of 230kV SS

In charge of 500kV TL

In charge of 230kV TL (including Underground TL) In charge of Sar

Ta Lin SS



9-1

9. Evaluation of the Project

9.1. Quantitative Evaluation

Benefits The following two ideas can be considered as benefits from the implementation of this project.

(1) Reduction of Transmission Line Losses By comparing the power flow in 2030 with and without this project, the transmission line losses

across the whole system are calculated as follows. In this calculation, thermal power generations in

Yangon city are assumed to be the same.

Figure 9.1-1 Comparison of the Power Flow in 2030 with and without this Project

Thus, a comparison of the power transmission line losses for the two is as follows.

Table 9.1-1 Comparison of Transmission Line Losses with without Difference

Outside 109.6 MW 127.3 MW

Area 64.4 MW 134.6 MW

Total 174.0 MW 261.9 MW 87.9 MW

In the 2030 grid configuration, there will be an 87.9 MW transmission line loss difference during

peak hours. If the power transmission losses are reduced, the difference will help curtail power

generation at thermal power plants, and the implementation of this project will create benefits.

(2) Reduction of Thermal Power Generation in Yangon city Without this project, transmission capacity from the northern hydropower and China, which have

low power generation costs, to Yangon city will be limited due to a transmission capacity bottleneck.

For this reason, contracts with rental thermal power plants in Yangon City, where power generation

costs are high, must be extended. By implementing this project, it will be possible to increase the

amount of power transmitted from the low-cost northern hydropower and China to Yangon city, and

avoid extending contracts with rental thermal power plants.

The following shows a comparison of power flow in 2030 with and without this project. In the case

with this project, the contracts with rental thermal power plants have not been extended, so the supply

capacities in Yangon city have decreased and the amount of power transmission from the north has

increased.

With this Project Without this Project

(Source: JICA Survey Team)




9-2

Figure 9.1-2 Comparison of the Power Flow in 2030 with and without this Project (change in operating amount of thermal power in Yangon city)

In the case without this project, part of the power flow from the north to the 500 kV PYG substation

will be transmitted to the 230 kV Kamarnat substation, but most of the power will be transmitted once

to the 500 kV HLT substation and electricity will be supplied to Yangon city from it. However, the 500

kV HLT substation receives 1,390 MW of electricity from the west and there is a limit on the

transmission capacity that can be supplied to the 230 kV system from the 500 kV HLT substation. As

a result, the power flow from the north into the 500 kV PYG substation must be limited. For this reason,

there will be a shortage of power in the city and it will be necessary to increase the amount of power

generated by thermal power plants, including rental thermal power plants in Yangon city, which have

a high generation cost.

Table 9.1-2 Comparison of Supply Capacity in 2030

With this Project Without this

Project

Supply From outside of Yangon city 5,555 MW 3,723 MW

From thermal power plants in Yangon

city 2,429 MW 4,199 MW

Demand Demand in substations 7,706 MW 7,706 MW

Transmission losses etc. 278 MW 216 MW

By implementing this project, it will be possible to stop rental thermal power plants (Phase I, II:

1,770 MW).

<Evaluation of the transmission line loss increase>

As the power supply inside the city is stopped, and power is transmitted from the northern area, this

increases the overall transmission line losses. In this case, the transmission line losses between the two

are compared as follows, resulting in an increase in transmission line losses of 206.5 MW.

Table 9.1-3 Comparison of Transmission Line Losses (change in operating amount of thermal power in Yangon city)

with without Difference

Outside 239.0 MW 127.3 MW

Area 229.4 MW 134.6 MW

Total 468.4 MW 261.9 MW - 206.5 MW

With this Project Without this Project






9-3

Based on the calculation method described in the previous section, the decrease in annual benefits

(2020 value) due to the increase in transmission line losses is as follows.

206.5MW x 0.553 x 8760 x 185.0 Kyat/kWh = 185,064 million Kyat (123.4 million USD)

<Overall benefits (2020 value)> The benefits are expected to be 505,718 million Kyat (337.1 million USD) annually in terms of fuel

cost savings by stopping high fuel cost rental thermal power plants (1,770 MW) and switching to low-

cost hydropower and imports from the neighboring countries. The increase in fuel costs due to an

increase in transmission line losses results in an annual increase of 185,064 million Kyat (123.4 million

USD). The shutdown of high-cost rental thermal power plants has a significant effect on reducing fuel

costs, and the total benefits are 320,654 million Kyat (213.8 million USD) per year. Greater benefits

can be expected than those that result only from the reduction of transmission line losses as described

in the previous section.

EIRR and FIRR

(1) FIRR DPTSC, the implementing agency for the Project, is in charge of the construction and management

of the transmission network as an internal agency of MOEE, but it does not receive revenue from the

transmission business; MOEE earns revenue by selling electricity procured from power generators

through DPTSC's transmission network. The revenue from the transmission business, i.e. DPTSC's

business revenue, can be regarded as the revenue from the sale of MOEE's electricity minus the

payment to the power producers.

In general, the benefits of transmission lines are as follows, and the revenues of transmission

projects are also derived from benefits 1 to 3.

1. Increase in revenue from sales of electricity due to increased power transmission

2. Reduction of power generation costs by reducing transmission losses

3. Reduction of power generation costs through procurement of cheaper power sources by

changing the power supply composition (in this case, since it involves an increase or decrease in

transmission losses, the increase or decrease in transmission losses is counted as an increase or

decrease in power generation costs)

In the FIRR calculation, the following approach was used to calculate the increase in business

income.

1. Increase in revenue from sales of electricity due to increased power transmission.

Considering the emergency power supply, the amount of electricity supplied to Yangon will not

change with or without the implementation of the project, and the revenue from the sale of electricity

by 1 will not change.

2. Reduction of power generation costs by reducing transmission losses.

Transmission losses will be reduced by the implementation of the project, resulting in higher

financial revenues, as payments to the power producers will be reduced.

3. Reduction of power generation costs through procurement of cheaper power sources by changing

the power supply composition.

This effect is excluded from the increase in financial revenue, as the scope of implementation by

the project to achieve this effect is considered to be limited.

Therefore, the only change in financial revenue due to the implementation of the project is the

reduction of payments to the power generation companies due to the reduction of transmission losses

in 2.

FIRR is calculated as follows by simply evaluating the transmission line loss reduction effect as the

benefit gained from implementing this project. FIRR = 5.6%.



9-4

Table 9.1-4 FIRR Calculation Sheet

2020 FIRR (Base Case) 5.6%

NPV -163.8

B/C 0.6 million USD

Maintenance Personnel

-6 2020 0.00 0.00 0.00 0.00

-5 2021 6.31 6.31 0.00 (6.31)

-4 2022 94.09 94.09 0.00 (94.09)

-3 2023 154.73 154.73 0.00 (154.73)

-2 2024 188.33 188.33 0.00 (188.33)

-1 2025 157.52 157.52 0.00 (157.52)

0 2026 32.51 32.51 0.00 (32.51)

1 2027 1.70 1.14 2.84 52.52 49.68

2 2028 1.70 1.14 2.84 52.52 49.68

3 2029 1.70 1.14 2.84 52.52 49.68

4 2030 1.70 1.14 2.84 52.52 49.68

5 2031 1.70 1.14 2.84 52.52 49.68

6 2032 1.70 1.14 2.84 52.52 49.68

7 2033 1.70 1.14 2.84 52.52 49.68

8 2034 1.70 1.14 2.84 52.52 49.68

9 2035 1.70 1.14 2.84 52.52 49.68

10 2036 1.70 1.14 2.84 52.52 49.68

11 2037 1.70 1.14 2.84 52.52 49.68

12 2038 1.70 1.14 2.84 52.52 49.68

13 2039 1.70 1.14 2.84 52.52 49.68

14 2040 1.70 1.14 2.84 52.52 49.68

15 2041 1.70 1.14 2.84 52.52 49.68

16 2042 1.70 1.14 2.84 52.52 49.68

17 2043 1.70 1.14 2.84 52.52 49.68

18 2044 1.70 1.14 2.84 52.52 49.68

19 2045 1.70 1.14 2.84 52.52 49.68

20 2046 1.70 1.14 2.84 52.52 49.68

21 2047 1.70 1.14 2.84 52.52 49.68

22 2048 1.70 1.14 2.84 52.52 49.68

23 2049 1.70 1.14 2.84 52.52 49.68

24 2050 1.70 1.14 2.84 52.52 49.68

25 2051 1.70 1.14 2.84 52.52 49.68

26 2052 1.70 1.14 2.84 52.52 49.68

27 2053 1.70 1.14 2.84 52.52 49.68

28 2054 1.70 1.14 2.84 52.52 49.68

29 2055 1.70 1.14 2.84 52.52 49.68

30 2056 1.70 1.14 2.84 52.52 49.68

NPV 417.86 254.05 -163.81

(at 10% Discount Rate)

Financial

Benefit (B)

Net

(B) - (C)Year

O&M costs

Operation

Activities

Construction

Total Costs

(C)

Construction

Work

Financial Costs (C)



9-5

(2) EIRR The EIRR calculation takes into account the change in the power supply mix, i.e., cheaper power

supply procurement by avoiding the extension of emergency power supply contracts, and the

associated increase in transmission losses; the Local Currency portion is considered non-tradable

goods, and the project cost converted from the price of the non-tradable goods by SFC is used.

In terms of the benefits gained from implementing this project, the EIRR is calculated as follows

by evaluating the fuel cost reduction effect of avoiding the extension of contracts with rental thermal

power plants in Yangon City. The EIRR is 21.4%.

Table 9.1-5 EIRR Calculation Sheet


2020 FIRR (Base Case) 21.4%

NPV 1,988.4

B/C 75.3 million USD

Maintenance Personnel

-6 2020 0.00 0.00 0.00 0.00

-5 2021 6.18 6.18 0.00 (6.18)

-4 2022 92.61 92.61 0.00 (92.61)

-3 2023 152.47 152.47 0.00 (152.47)

-2 2024 185.49 185.49 0.00 (185.49)

-1 2025 155.08 155.08 0.00 (155.08)

0 2026 32.00 32.00 0.00 (32.00)

1 2027 1.70 1.14 2.84 213.77 210.93

2 2028 1.70 1.14 2.84 213.77 210.93

3 2029 1.70 1.14 2.84 213.77 210.93

4 2030 1.70 1.14 2.84 213.77 210.93

5 2031 1.70 1.14 2.84 213.77 210.93

6 2032 1.70 1.14 2.84 213.77 210.93

7 2033 1.70 1.14 2.84 213.77 210.93

8 2034 1.70 1.14 2.84 213.77 210.93

9 2035 1.70 1.14 2.84 213.77 210.93

10 2036 1.70 1.14 2.84 213.77 210.93

11 2037 1.70 1.14 2.84 213.77 210.93

12 2038 1.70 1.14 2.84 213.77 210.93

13 2039 1.70 1.14 2.84 213.77 210.93

14 2040 1.70 1.14 2.84 213.77 210.93

15 2041 1.70 1.14 2.84 213.77 210.93

16 2042 1.70 1.14 2.84 213.77 210.93

17 2043 1.70 1.14 2.84 213.77 210.93

18 2044 1.70 1.14 2.84 213.77 210.93

19 2045 1.70 1.14 2.84 213.77 210.93

20 2046 1.70 1.14 2.84 213.77 210.93

21 2047 1.70 1.14 2.84 213.77 210.93

22 2048 1.70 1.14 2.84 213.77 210.93

23 2049 1.70 1.14 2.84 213.77 210.93

24 2050 1.70 1.14 2.84 213.77 210.93

25 2051 1.70 1.14 2.84 213.77 210.93

26 2052 1.70 1.14 2.84 213.77 210.93

27 2053 1.70 1.14 2.84 213.77 210.93

28 2054 1.70 1.14 2.84 213.77 210.93

29 2055 1.70 1.14 2.84 213.77 210.93

30 2056 1.70 1.14 2.84 213.77 210.93

NPV 26.77 2015.19 1988.41

(at 10% Discount Rate)

Economic

Benefit (B)

Net

(B) - (C)

O&M costsTotal Costs

(C)

Operation

Year Activities

Construction

Construction

Work

Economical Costs (C)



9-6

In the above calculation, the unit price for power received from the neighboring countries is assumed

to be 80% of rental thermal power plants, but if it is assumed to be 90% of rental thermal power plants,

the benefit will be reduced to 99.15 million USD, and EIRR = 18.1%.

9.2. Reducing Greenhouse Gas Emissions The implementation of the project is expected to reduce greenhouse gas emissions from the fuel

combustion of thermal power because implementing the project will make it possible to avoid the

extension of thermal power contracts for the emergency power supply in Yangon City, and will

enable the supply of power to Yangon City through hydropower in the north and transmission from

other countries. However, the power supply from inside the city will be shut down and power will

come from the north, increasing the overall transmission losses.

The greenhouse gas emission reduction amount was calculated by subtracting the increase in

emissions due to increased transmission losses from the greenhouse gas emission reduction by

replacing the electricity supplied by emergency power sources in Yangon before the project with

hydropower sources in the north and power sources from other countries after the project. The

format of the JICA Support Tool for Change Measures was used as the calculation tool. The amounts

of power supply and transmission losses used for the comparison before and after the

implementation of the project were calculated in accordance with the previous section. The CO2

reductions were calculated under the following conditions.

Electricity will be supplied by an emergency power source before the project is implemented

(natural gas with an emission factor of 56,100 kg/TJ (Appendix 2 of the Support Tool)

assuming 35% efficiency)

After the implementation of the project, the following power sources will be used to supply

electricity

3 months of rainy season: supply from northern hydropower, and neighboring countries'

hydropower

9 months of dry season: supplied by neighboring countries (emission factor for grid

electricity is 672 g-CO2/kWh, which is the Asian average)

The result was a reduction of 615,703 tCO2/year. The calculation table is shown in Table 9.2-1.



9-7

Table 9.2-1 -Calculation Table for Greenhouse Gas Emissions Reduction

(Source: Format of the JICA Climate Change Support Tool)

12. Transmission System Efficiency Improvement

Project Name

Country

Emission ReductionValue Unit

ERy Emission reduction 615,703 tCO2/year

BEy Baseline emissions 6,441,799 tCO2/year

PEy Project emissions 5,826,096 tCO2/year

Input *Input only orange cell

Parameter Description Value Unit

Amount of electricity from power sources (emergency generators) in base line in year y 11,163.7 GWh/year

Amount of electricity from power sources (hydropower) during wet seasons in the project in year y 2,790.9 GWh/year

Amount of electricity from power sources (from other countries) during dry seasons in the project in year y 8,372.8 GWh/year

Increase in transmission line losses in the project in year y 1,000.3 GWh/year

National Power Transmission Network Development Project Phase III

Myanmar

Calculations

Value Unit

615,703 tCO2/year

6,441,799 tCO2/year

Amount of electricity from power sources in base line in year y 11,163.7 GWh/year

CO2 emission factor of electricity (emergency generators) 0.577 tCO2/MWh

Power generation effiency of emergency generators 35%

Effective CO2 Emission Factor (kg/TJ) Natural Gas 56,100.0 kg/TJ

5,826,096 tCO2/year

Amount of electricity from power sources during wet seasons in the project in year y 2,790.9 GWh/year

CO2 emission factor of electricity (hydro) 0.0 tCO2/MWh

Amount of electricity from power sources during dry seasons in the project in year y 8,372.8 GWh/year

CO2 emission factor of electricity (other countries Asia) 0.672 tCO2/MWh

Increase in transmission line losses in the project in year y 1,000.3 GWh/year

CO2 emission factor of loss 0.266 tCO2/MWh

Baseline emission

Project emission

Emission reduction

Table Default Values

Effective CO2 Emission Factor (kg/TJ) (Natural Gas) 56,100 kg/TJ

Power generation effiency of emergency generators 0.35

CO2 emission factor of electricity (Hydropower) 0 tCO2/MWh

CO2 emission factor of electricity (From other countries) 0.672 tCO2/MWh

CO2 emission factor of electricity (Myanmar) 0.266 tCO2/MWh



9-8

9.3. Performance Effectiveness Indicators

(1) Performance Effectiveness Indicators The performance indicators are set as the availability (%) of the new 500 kV transmission lines, 230

kV transmission lines, and 500 kV substations to be built under the Project at maximum load and the

amount of power sent at the end of transmission lines in 2028, after the Project starts operation. The

performance effectiveness indicators are shown in Table 9-1.

Table 9-1Operational Effectiveness Indicators Number of

lines/units

Rated capacity

of equipment

(MVA)

2028

Maximum

load (MW)

Target value 1

Operating rate

at maximum

load

Target value 2

Amount of

electricity at

transmission end

(GWh/year)

500 kV Pharyargyii -

Sartalin transmission line

2 4,420

1,451 33%. 7,888

500 kV Sartalin

Substation 500 kV/230

kV Transformer

3 1,500 1,445 96%. 7,862

500 kV Sartalin

Substation - 230 kV

Hlawga Substation

4 1,492 i 914 61%. 4,844

500 kV Sartalin

Substation - 230 kV East

Dagon Substation

2 1,391 333 24%. 1,712

230 kV Hlawga

Substation - 230 kV

Thaketa Substation

2 777 ii 517 67%. 2,400

(2) Calculation of Each Indicator Each indicator was calculated according to the results of the power flow calculation for 2028 shown

in Figure 9.3-1 Power Flow Diagram in 2028 after completion of . The power factor is assumed to

be 90%.

During peak demand Off-peak demand Figure 9.3-1 Power Flow Diagram in 2028 after completion of Phase III

The operating rate of facilities at maximum load is given by

Operating rate at maximum load (%) = Maximum load (MW) / Rated capacity (MVA) x Power

Factor

Note that for the sections between the 500 kV Sartalin substation and 230 kV Hlawga substation,



9-9

and between the 230 kV Hlawga substation and 230 kV Thaketa substation, the capacity of these

sections is equal to the capacity of the underground line section because the capacity of the

underground line section is smaller than the capacity of the overhead line section.

The amount of energy sent at the end of the transmission line (GWh/year) was estimated using the

following method.

Off-peak demand was set at 50% of maximum demand.

The annual amount of energy transmitted was the average of the energy transmitted during

maximum and off-peak demand.

The power generated in Yangon during off-peak demand was assumed to be the same as the

power generated during peak demand. The reasons are given below.

In the power supply operation for one day in April 2019 shown in Figure 9.3-2, thermal

power plants have hardly changed their output, and the supply-demand balance is

maintained by adjusting the output of hydroelectric power plants. For this reason, it was

assumed that there would be no adjustment of thermal power output during the day or

night.

In the plans for this project, the thermal power plants in Yangon are almost at full output,

and yet the project is considering transmitting the necessary power from the north. On the

other hand, during the rainy season, the amount of electricity that can be generated by the

hydroelectric power plants is higher, so there is a possibility that surplus electricity from

the north can be transmitted to Yangon, thereby reducing the amount of electricity

generated by the thermal power plants. However, the appropriateness of the additional

transmission lines needed to curb the output of the thermal power plants in Yangon during

the rainy season is considered to be something to be explored after the implementation of

this project, which is urgently needed to ensure stable supply in Yangon. The

appropriateness of these additional transmission lines will be considered by taking into

account the type of contracts with thermal power plant IPPs (feed-in tariff, etc.), the

development plans for hydropower plants, the amount of electricity that can be generated

during the wet and dry seasons, and the costs of generation and transmission lines. For

this reason, in this project, the same amount of power generated was assumed for the wet

and dry seasons without anticipating any change in the amount of power generated by

thermal power plants during the wet and dry seasons.

Therefore, it was assumed that the power generated in Yangon would be the same during

both peak and off-peak demand.

Figure 9.3-2 One-day Operation of Power Generation in April 2019



9-10

(3) Voltage Drops and Transmission Loss Indexing As described in 1.5.4, the voltage in the city center tends to decrease in the Yangon City 230 kV

system, and power capacitors need to be installed to improve voltage drops. In order to improve the

voltage drop issue, power capacitors should be installed on the load side of Yangon's 230 kV system

at Thaketa, Ahlone, and Thanlyin, or on the lower 66 kV and 33 kV systems. However, the load power

factor assumed in this planning study is 90%, which is an approximate setting, and the distribution of

grid voltage can only be approximately calculated. Therefore, in order to study the effective amount

and location of power capacitors to be installed, it is considered that this matter should be studied in

detail by monitoring the load power factor, power flow, and voltage during actual operation after the

completion of Phase III. Therefore, voltage drop was not adopted as an indicator for this project. After

the completion of Phase II, it will be necessary to investigate the degrees of voltage drops, the

magnitudes of power flows in the transmission lines, the magnitudes of loads in the substations, the

power factors of the loads, and the power generated, to study the locations and the capacities of the

capacitors to be installed. It should be noted that power capacitors can be installed within about two

years of planning.



10-1

10. Preliminary Data Collection Survey for Plan for Power Grid Extension to Mawlamyaing

10.1. Outline of the Survey A preliminary data collection survey was conducted for the Yangon region, particularly on the

expansion of the bulk power transmission lines between Yangon and Mawlamyaing. This chapter

presents an overview of the survey. The results will be reported separately in February 2021.

In Myanmar, there is an urgent need to improve the bulk power transmission lines in the northern,

western and southeastern regions of the country, with Yangon at the center. The 500 kV system from

the north to the Yangon area is already under construction in Phase I/II, and there is an urgent need to

improve the power transmission network to the southeast.

Mawlamyaing is a city located about 300 km southeast of Yangon, with plans for an industrial park

in the vicinity. A power plant is planned in the Dawei district (Kanbouk) in the south. In addition, an

interconnected transmission line from Thailand is planned at Myawaddy, on the border with Thailand,

northeast of Mawlamyaing. Since there is only a single circuit line of 230 kV between Mawlamyaing

and Pharyargyi, which does not meet the N-1 requirement, and the load is getting heavier, a new 230

kV transmission line with double circuits is currently planned to be built by DPTSC. In addition, a

230 kV transmission line with double circuits between Mawlamyaing and Myawaddy was recently

constructed.

10.2. Data Collection on System Configuration

Current Status and Plans for System Configuration

(1) Current Status of Grid Structure The system diagram from Pharyargyi to the southeast, obtained from DPTSC, is shown in Figure

10.2-1. 500 kV and 230 kV systems are planned from Pharyargyi to the southeast.

Source: left: obtained from DPTSC, November 2018; right: prepared by the JICA Survey Team.

Figure 10.2-1 System Map of the Southeast from Pharyargyi



10-2

Source: Prepared by JICA Survey Team

Figure 10.2-2 System Configuration in Eastern Yangon and Southeast from Pharyargyi

(2) Consideration of Power System Planning The power flows for each section of the system from Pharyargyi to the southeast were estimated

and the adequacy of the system plan was discussed.

(3) Assumptions regarding Power Demand Based on the power demand forecast in the JICA Master Plan, the maximum demand at the district

level was assumed based on the maximum demand forecast for the region and the population ratio.

Kamarnat Sittaung

230/33/11 kV 50 MVA

Thaton.

Mawlamyaing

230/66/11 kV

150 MVA (->2x100)

Myanmar Lighting

IPP 230 MW

Myaungtagar

Thilawa

Thanlyin

Phryargyi

2 x 605 MCM

61 miles (to

Thanlyin)

2 x 605 MCM

8.4 miles (Thilawa

In/Out)

2 x 605 MCM

39.97 miles

2 x 605 MCM

36.6 miles

Tharyargone

2 x 605 MCM

58.8 miles (336.4 MCM per

side?)

2 x 605 MCM

60.25 miles

2 x 605 MCM

49.77 miles

Hlawga

Thaketa

Shewtaung

2 x 605 MCM

19.14 miles

Minhla

2 x 605 MCM

65.39 miles

2 x 605 MCM

62.96 miles

1 x 795 MCM

13.85 miles

1 x 795 MCM

94.01 miles

2 x 605 MCM

7.7 miles

2 x 605

MCM

12.4 miles

(Dagon

(East) In/Out)

Taungoo

Lawpita

Pyu

Kun

1 x 795 MCM

60.55 miles

Thaephyu

2 x 265/35 sqmm

40.28 miles

50.95 MW Myawaddy.

Kanbouk.

1,230 MW

East

Dagon

1 x 795 MCM



10-3

(4) Existing Power Supply The existing power sources connected to the transmission system are three units of EPGE's Thaton

generators, with a total capacity of 50.95 MW, and Myanmar Lighting Company's IPP, with a total

capacity of 230 MW.

New Power Plant Construction Plans MOEE is planning to build an LNG-fired power plant in Kanbauk (Dawei district).

It was noted that the power supply envisioned from DPTSC to Kanbouk is uncertain and therefore

does not need to be considered in this planning survey. Therefore, this power source will not be

considered in this survey.

There are plans for an interconnection with Thailand.

Approximate Current Forecast Approximate power flows were estimated. The direction and magnitude of the power flows vary

greatly depending on the power outputs of power sources and the amount of power demand.

Based on the approximate stability estimates, it is considered that stable transmission of electricity

may be difficult in some cases, depending on the power outputs of the power sources and the amount

of power demand, with the existing single circuit of a 230 kV line and the double circuits of a 230 kV

line.

For this reason, a new 500 kV transmission line with double circuits is to be constructed, and the

following system configuration is considered.

Existing: 230 kV 1cct Kamarnat - Mawlamyaing

New: 230 kV 2cct Kamarnat - Mawlamyaing

New: 500 kV 2cct Pharyargyi - Mawlamyaing

Source: Prepared by JICA research team

Figure 10.2-3 Recommended System Configuration

In the future, it will be necessary to examine the amount of power that can be transmitted in detail

by calculating the stability of the system, including the interconnection with Thailand.

Kamarnat Sittaung Thaton

.

Mawlamyine

Phryargyi

Myawaddy

Thailand

500 kV

230 kV

230 MW 50 MW



10-4

10.3. Data Collection on New Power Transmission Lines

Conceptual Study of Transmission Line Routes

(1) Methodology of the Study on Power Transmission Line Routes The study on the 500 kV transmission line route between Pharyargyi and Mawlamyaing, which is

the target of this project, was conducted via desk research using the latest map data, such as Google

Earth.

(2) Location of Substations The substations to be included in this project are the 500 kV Pharyargyi substation, currently under

construction, and the new 500 kV Mawlamyaing substation.

Source: Prepared by JICA research team from Google Earth

Figure 10.3-1 500 kV Mawlamyaing Substation

(3) Transmission Line Routes

Overview of Transmission Line Routes A general overview of the 500 kV transmission line route between Pharyargyi and Mawlamyaing,

which is the target of this project, is shown in Figure 10.3-2. The route is based on the south of the

existing 230 kV Kamarnat-Thaton-Mawlamyaing transmission line route, which has the shortest

distance between Pyaryargyi and Mawlamyaing and easy access roads during construction. In addition,

the planned future 230 kV Kamarnat-Thaton-Mawlamyaing transmission line route was also

considered. The existing 230 kV Kamarnat-Thaton-Mawlamyaing transmission line route is in the

north, between Mawlamyaing and the Thaton substation. In this project, the shortest route to the north

of the conservation forests around Kamarnat is proposed.



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ource: Prepared by JICA research team from Google Earth

Figure 10.3-2 Overview of the Transmission Line Routes

Figure 10.3-3 Status of Conservation Forests and Other Areas near Transmission Line Routes

; New 500 kV Pharyargyii―Mawlamyaing

(210km) ; Existing 230 kV Kamarnut―Thaton― Mawlamyaing

; New 230 kV Karmanat―Pharyargyii



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10.4. Data Collection for Construction and Expansion of Substations

500 kV Pharyargy Phayagyi substation is under construction in the Phase II Project and 500 kV H-GIS switchgear for

Mawlamyaing’s new 500 kV Substation, and auxiliary equipment, such as transmission line protection

panels, are also being installed in the Phase II Project. Therefore, it is not necessary to install new

equipment for 500 kV transmission lines to Mawlamyaing substation and the scope of work in the new

project will cover only the connection of 500 kV transmission lines to the gantry structures in Phayagyi

substation.

Figure 10.4-1 Layout of Phayagyi Substation under Phase II Project

500 kV Mawlamyaing

(1) Location of Substation It is necessary to secure the space for the new 500 kV substation at the northern side of the existing

Mawlamyaing 230 kV substation and construct the new 500kV substation in that space, because the

existing Mawlamyaing 230 kV substation doesn’t have sufficient space for expansion as a 500 kV

substation.

(2) Equipment configuration The new Mawlamyaing 500kV substation will use H-GIS with a one and a half circuit breaker

system for 500 kV switchgear and AIS with a double busbar system for 230 kV switchgear, in

reference to similar projects like Phase I and Phase II of the JICA project, subject to securing enough

space for the construction of H-GIS. The major equipment in the new Mawlamyaing 500 kV substation

is shown in the following table:

Sar Ta Lin S/SMawlamyaing S/SNorth Side

500kV Switchyard

230kV Switchyard



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Table 10.4-1 Equipment Configuration of New Mawlamyaing 500kV Substation Equipment name Overview Remarks

500kV Switchgear

(H-GIS)

2 feeders for Pyaji substation

x 2 feeders for Daway

Power line spare x 4 feeders

500/230kV transformer connection x 2 feeders

1+1/2CB method

230kV switchgear

(AIS)

2 feeders for 230kV substations in Mauramyne

2 feeders for Myawaddy Substation

Power line spare x 4 feeders

500/230kV transformer connection x 2 feeders

Main line contact x 1

dual bus bar

system

500/230kV

transformer

Outdoor installation, single phase, oil type,

ONAF/ONAN cooling system

166.7 MVA/phase x 7

OLTC included

On-site power

supply

400/230V AC panel, 110V DC panel, 48V DC panel,

DC battery, emergency generator, internal

transformer (33/0.4kV)

Protection and

control equipment

SCADA, power line protection equipment,

transformer protection equipment, etc.

10.5. Environmental and Social Considerations

Environmental Considerations Strategy of the study is described below. The results of the study will be reported sepaetely

following further technical examination in Feburary 2021.

(1) Confirmation of the Situation regarding Protected Areas, Key Biodiversity Area and Areas Surrounding the Planned Transmission Line Route

Status of Protected Areas and Reserved Forests There are no protected areas and or Key Biodiversity Areas (KBAs) on the planned transmission

line route from Phayargy to Mawlamyaing, but there is one reserved forest, Kalama Taung Reserved

Forestassumed to be a commercial conservation forest (e.g. rubber plantation), judging by satellite

images, as shown in Table 10.5-1. According to a Forest officer ofthere, Kalama Taung Reserved

ForesForest, it is defined as a Reserved Forest for 3 purposes;: (a) commercial reserved forest; (b)

local supply reserved forest; (c) watershed or catchments protection reserved forest as described in the

Forest Law (2018). Also, it is It was also confirmed that this Reserved Forest can be modified by

following the necessary procedure. In addition, although the actual area of influence on the

environment differs depending on the impact item, protected areas/reserved forests that exist within a

range of 10 km from the project target area were identified to secure a safe margin for this survey.



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Source: Forest Department of related townships (2019); Protected areas and Reserved Forests

Figure 10.5-1 Protected Areas/KBA (left) and Reserved Forests (right) near the Project Site

Status of Cultural Heritage Sites Surrounding the Project Site There are no special cultural heritage sites on the planned transmission line route from Pharyargyi

to Mawlamyaing.

(2) Outline of Environmental and Social ConsideratoinsCategories required in accordance with the JICA Guidelines for Environmental and Social Considerations

Procedures in line with the EIA Procedure (2015) in Myanmar In accordance with the EIA Procedures, stipulated in December 2015, as prepared by the Ministry

of Environmental Conservation and Forestry (the former name of the Ministry of Natural Resources

and Environmental Conservation (MONREC)), the Project can be categorized as “EIA or IEE is

required”, as shown in Table 10.5-1.

Table 10.5-1 EIA/IEE/EMP Requirements related to the Project in Myanmar

No. Type of Investment Project Size of Project

which requires IEE Size of Project which requires EIA Notes

ENERGY SECTOR DEVELOPMENT

27 Electrical Power Transmission Lines ≥ 230 kV

All sizes All activities where the Ministry requires that the Project shall undergo EIA

-

* EIA: Environmental Impact Assessment

IEE: Initial Environmental Examination

Source: Extract from EIA Procedures (2015)

Procedures in line with the JICA Guidelines for Environmental and Social

Considerations There are descriptions concerning the illustrative list of sensitive sectors, characteristics, and areas

in Appendix 3 of the JICA Guidelines for Environmental and Social Considerations (2015), and the

Project was compared/summarized with these descriptions. With regard to the number of Project-



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affected people during the construction of the new substations and the development of transmission

lines, the relocation of residents, businesses, and commercial activities due to land acquisition would

be avoided to the extent possible. Therefore, it is considered that it does not fall under sensitive sectors,

characteristics, and areas in Appendix 3 of the JICA Guidelines for Environmental and Social

Considerations (2015).

Table 10.5-2 Outline of the Project’s in line with the JICA Guidelines for Environmental and Social Considerations (2010)

Category Contents Outine of the Project

1. Sensitive Sectors

(6) Power transmission and distribution lines involving large-scale involuntary resettlement, large-scale logging, or submarine electrical cables

Technically, large-scale involuntary resettlement and large-scale deforestation can be avoided

2. Sensitive Characteristics

(1) Large-scale involuntary resettlement (2) Large-scale groundwater pumping (3) Large-scale land reclamation, land development, and land clearing (4) Large-scale logging

Technically, (1) and (4) can be avoided. (2) and (3) are not applicable.

3. Sensitive Areas

(1) National parks, nationally-designated protected areas (coastal areas, wetlands, areas for ethnic minorities or indigenous peoples and cultural heritage, etc. designated by national governments)

No direct impact is expected for protected areas, cultural heritage, and or Key Biodiversity Areas (KBA). Although the planned transmission line route passes through one reserved forest, this it can be changed through appropriate procedures because if it is a Kalama Taung Reserved Forest, it which is defined as a commercial//local supply/watershed or catchments protection reserved forestcommercial reserved forest. In addition, it does not modify vulnerable areas, such as areas in danger of soil erosion, or areas with a remarkable tendency towards desertification, will not be modified.

(2) Areas that are thought to require careful consideration by the country or locality a) Primary forests or natural forests in tropical areas b) Habitats with important ecological value (coral reefs, mangrove wetlands, tidal flats, etc.) c) Habitats of rare species that require protection under domestic legislation, international treaties, etc. d) Areas in danger of large-scale salt accumulation or soil erosion e) Areas with a remarkable tendency towards desertification

Note: The numbers listed correspond to the numbers listed in Attachment 3 of the JICA Environmental and Social Considerations

Guidelines (2010).

Source: The JICA Environmental and Social Considerations Guidelines (2010), with modifications by the JICA Survey Team

Social Considerations Strategy of the study is described below. The results of the study will be reported sepaetely

following further technical examination in Feburary 2021.

(1) Satellite Photo Analysis of the Proposed Site for the 500kV Mawlamyaing Substation

The 500kV Mawlamyaing Substation (80 acres/32.4 ha) is proposed to be in Mawlamyaing District,

Mon State.

Satellite photos of the area surrounding the proposed site, as well as a close-up of the proposed site,

were collected from Google Earth. The oldest available photos were taken in the year 2002, and the

most up-to-date were taken in 2019. The latest photos, taken in July 2019, are not suitable for the

analysis since the site is covered by clouds. The photos taken in December 2018 will be used to identify

and count the assets (such as structures, trees and crops) at the site and in the area surrounding the site

to understand the significance of the impacts of the substation construction.

(2) Satellite Photo Analysis of the Proposed Route for the 500kV Transmission Line Between Pharyargyi and Mawlamyaing Substations

The proposed route for the transmission line between Pharyargyi and Mawlamyaing Substations

will be studied using satellite photos of the surrounding area collected from Google Earth. Land use

and locations of structures and towns will be analyzed to understand the types and significance of the

impacts of the transmission line construction. Advice for the detailed study of the ROW location will



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be listed to avoid and minimize the negative impacts.

(3) Preliminary Alternative Study for the Substation and Transmission Line In addition to the proposed project, the no-project case, and a case with a different site will provide

three (3) alternatives for a preliminary, qualitative comparative study.

Source: JICA Study Team, Google Earth (December 2018)

Figure 10.5-2 Satellite Photos of the Proposed Substation Site and Surrounding Area

Source: JICA Study Team, Google Earth

Figure 10.5-3 Satellite Photos of the Proposed Transmission Line Route

i Capacity of four combined lines in the underground line sinusoidal section (case with increased gap between

phases) ii Capacity of two lines in the underground line conduit section

Religious school Gayng River

6. Conceptual Design

Documents

Transcript of 6. Conceptual Design