Shunt Reactors

© ABBSlide 1 AOctober 3, 2016October 3, 2016

Shunt ReactorsOptimizing Transmission Voltage System

Zahra Norouzian, Electrical Engineer, ABB Transformers and Reactors, Sep 6 / 2016


ABB oil immersed ReactorsAgenda

Introduction ABB Transformers, Ludvika

Why shunt reactors?

General Design

Variable Shunt Reactors (VSR)

Design

Applications and benefits

References VaasaLudvika

Stockholm


ABB Transformers LudvikaLarge power transformers & Shunt Reactors

World wide responsibility for Shunt reactors andHVDC transformers within ABB

Competence center for transformers world wide

Development team for TrafoStar (ABB Technology)

Complete product range for bushings, tap changersand insulation kits

More than 1000 reactors to all continents.

Tailor made reactors for each specific networkconfiguration.

Testing facilities up to the largest units in voltage andpower.


ABB TransformersReactor Portfolio

ABB – Ludvika

Reactive power

Single phase up to 133Mvar (Full bank 400Mvar)

Three phase up to >300Mvar

Voltage

up to >765kV

Testing facilities up to the largest unitsin voltage and Mvar

ABB – Vaasa

<72,5 kV up to 63 Mvar

72,5 - 145kV up to 25 Mvar


Reactor Power CompensationWhy Shunt Reactors?


Reactive Power CompensationWhat is reactive power? Shunt Reactor

1. Stability on long line transmissions2. Voltage control during light load conditions

Reactor restores voltage to specifiedvalue

Voltage increase fromcapacitive generation

X

X

1

U

XQ

QQ

QX


Reactive Power CompensationVoltage profiles and Shunt reactors

U1 U2

1,0 pu

P2, Q2

U2U1

(R) + X

Q U1 U2

1,0 pu

U1 U2

1,0 pu

Reactive power balance

Decreased load

Fixed power compensation


Reactive Power CompensationVoltage profiles and Shunt reactors

U1 U2

1,0 pu

U1 U2

1,0 pu

Reactor power less thanrated power.

Variable reactive power

Increased load


Shunt Reactor (SR): The most common device for controlling voltage stability. TheSR absorbs reactive power

Variable Shunt Reactor (VSR): The VSR also absorbs reactive power but allows fordynamic compensation, e.g. when load conditions or generation of reactive powerare varying

Synchronous Generators: Can be used not only for generating active power, butalso to both generate and absorb reactive power

Static Var Compensator (SVC): Provides very fast regulation of consumed orgenerated reactive power. Great possibilities but at high cost

Transformers with regulation: Can to some extent be used as their consumption ofreactive power depends on the tap position

Reactive Power CompensationDevices for reactive power compensation


ReactorDesign Concept


Rigid gapped core limb for low sound level

1. Core segments of grain oriented steel core sheetbonded by epoxy

2. Very stiff steatite spacers

3. Spacers are machined to exactly the same height

Precision crafted process ensures:

Small axial movements

Low vibrations & sound

Reactor design: Gapped core conceptLow sound


Extreme magnetic forces between the segments, up to 40 tons Long time mechanical stability is the main engineering challenge Requirements Pressure on the gapped limbs Precision in manufacturing of the segments and assembly. Tolerances on flatness and total height < 0,1 mm.

General DesignMechanical forces


General DesignFlux Control

Cross flux plate

The introduction of the cross flux plate makes it possible toprevent mechanical resonance in the core frame.

Control of leakage flux

Reduces magnetic losses

Reduce temperature in yokes


Earthed shieldno stress concentrationtowards core or winding

Winding centre entry andground potential towards yokesreduces overall size and losses

HV line terminal

General DesignWinding arrangement


Seven 3-phase shunt reactors

150 Mvar, 400 kV

5-23 years in operation

General DesignLong term stability: Field Measurement


General DesignLong term stability: Field Measurement

-10

-5

0

5

10

0 5 10 15 20 25YEARS IN SERVICE

Deviation from factory sound power level [dB(A)]

No correlation with number years in service

Robust design, durable materials and precision in manufacturing process important for long-termstability


0

50

100

150

200

250

1996/05 1999/02 2001/11 2004/08 2007/04 2010/01 2012/10 2015/07

Max

sin

gle

peak

val

ue [µ

m]

Date of testing

Tank vibrations, max single peak value [µm]

General DesignTank vibrations

Limit according to IEC and ANSI/IEEE: 100 µm max single peak


Internal noise control only:Sound power level 80 – 95 dB(A)Sound pressure level 65 – 75 dB(A)

With sound panels:Sound power level 70 – 85 dB(A)Sound pressure level 55 – 65 dB(A)

With sound enclosure:Sound power level 65 – 80 dB(A)Sound pressure level 50 – 60 dB(A)

General DesignSound reduction – Typical sound levels


Variable Shunt ReactorDesign


Neutral

Phaseterminal

NeutralPhase

terminal

OLTC An unconventional Reactor built onconventional technology

Variable Shunt ReactorDesign: Winding Concept


Fixed Shunt Reactor Variable Shunt Reactor

Limits for OLTC diverter switch: Maximum rated step voltage

Maximum through current

Switching capacity

Variable Shunt ReactorTap Changer Appearance


Variable Shunt ReactorDesign: Feasible Mvar Output Ranges

Blue: Traditional

Red: Latest

Example:50-100 Mvar345 kV


System Aspect and Design for VSRTap Changer Appearance


Variable Shunt ReactorApplications and References


Variable Shunt Reactor ApplicationsSuitable for different Applications

The is an optimum reactor rating at a certain load

Load varies with time Seasonal variations Daily variations

Shunt reactors are by traditionfixed in rating

Switching fixed reactors in andout leads to Voltage steps Wear on breakers Non-optimal compensation

We cannot today foresee the gridconditions of the future


Variable Shunt Reactor ApplicationsWind Parks

Grid codes specify the amountof reactive power exchanged with the maingrid.

Unpredictable and fluctuating active powerexchange

The variations in reactive powerconsumption with varying wind-powerproduction require control: SVC Variable shunt reactor Fix shunt reactor

Benefits: Gives the necessary regulationcapabilities in all winds conditions


Variable Shunt Reactor ApplicationsLoad variations in regular networks

Weak grids, larger voltage variationsand variations in reactive power flow

Interaction with other types ofinstallations, e.g. SVC’s, HVDCtransmission links.

Controllability of the system increase inimportance

Increased demands on flexibility

Power quality is important

Benefits: Loss optimization, limitfluctuations in reactive power, regulationcapabilities, power quality


Variable Shunt Reactor ApplicationsOthers

Solar Panels

A VSR is an option when transient conditions arealready been taken care of, but some slow"tuning" is of added value.

A VSR will secure reactive reserves by "tuning"the reactor to give optimal headroom in SVC'sand synchronous compensators.

A VSR may save losses by "fine-tuning", allowingSVC's to operate in "minimum losses“ position.


Variable Shunt Reactor ApplicationsDenmark: Full use of VSR benefits

1: 50-110 Mvar, TC in min Mvar positionwhen cable is energized.2: 70-140 Mvar, to minimize voltagejump min Mvar position when switchedin.3: 70-140 Mvar, to minimize voltagejump min Mvar position when switchedin.4: 120 Mvar, compensation of sea cablefrom wind mill park.5: 60 -120 Mvar, 2 units to compensatefor variable wind power generation andloss optimization.

1

2

3

45


Variable Shunt Reactor ApplicationsNorway (Statnett): Voltage Stabilization

Strategic decision to use only VSRs for flexibility to meet future gridconditions (Long transmission lines, hydro power fluctuations).

Additional benefits

Reduced voltage jump at switching on operation.

Adjusting of seasonal related loads and daily dependable loads.

Flexible spare unit, bringing possibility to move the reactor to otherlocations.

Reduction of number of breakers. No parallel fixed reactors.


© ABB Group

October 3, 2016 | Slide 32

Variable Shunt Reactor ApplicationsDominion (VA)

Eliminates air core reactors on a three winding transformer.

Smaller footprint transformer

No need of intermediate transformer

Minimize number of breaker operations

Extended use of cables put higher demand on reactive power compensation.

Reactor power compensation from generators not longer reliable


Variable Shunt ReactorWorld Wide References

Customer Voltage (kV) Rating 3-phase - Mvar Year of delivery Customer Voltage (kV) Rating 3-phase - Mvar Year of delivery

Ghana, Africa 161 9-18 4 units 19891 units 2001 Vestas - Mexico 35 37 2 unit 2013

GEW, Köln, Germany 110 10-30 1 unit 1996 Center Point Energy, Texas, USA 143 25-50 1 unit 2014

Channel Islands, UK 132 7-16 2 units 1999 Jersey electricity - France 90 40 1 unit 2014

Sonabel, Burkina Faso, Africa 225 13-30 1 unit 2004 Cobra - Spain 161 9 4 unit 2014

Statnett, Norway 420 120-2001 unit 20082 units 20102 units 2010

City of Garland - Texas, USA 345 50-100 2 units 2015

E-Co Vannkraft, Norway 420 120-200 1 unit 2010 Kazakstan - Aktogai 10 3,8 2 units 2015

Dominion Virginia, USA 242 50-100

3 units 20094 units 20101 unit 20141 Unit 2016

BKK - Norway 420 90-200 2 units 2016

Svenska Kraftnät, Sweden 400 110-180 1 unit 2010 Eversource 345 70-160 2 units 2017Energinet dk, Denmark 235 60-120 2 units 2011 Energinet dk, Denmark 235 60-120 1 units 2017

Repsol - Libya 11 15,33 1 unit 2006Enercal – New Zeland 35 7,57 1 unit 2011

Statnett, Norway 420 90-200 8 units 2012 - 20131 unit 2014

Sharyland Utilities - Texas, USA 345 50-100 1 unit 2013

Energinet dk, Denmark 40050-110

70-140

3 units 20131 unit 20152 units 20131 unit 2015


Variable Shunt ReactorsSummary

SR used for voltage stability by consuming reactive power

SR are specialized products with substantial engineering challenges

SR: magnetic forces during normal operation

TFO: mechanical forces during short circuit

Manufacturing accuracy is requested to make reliable shunt reactors.

VSR is a new, advanced product type that provides:

Unique possibilities for variable network control

Variable ratings 50-100%

Several economical benefits

VSR customer references

Shunt Reactors

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