VISVESVARAYA TECHNOLOGICAL UNIVERSITY ...

VISVESVARAYA TECHNOLOGICAL UNIVERSITY Belgaum-590014, Karnataka

PROJECT REPORT

ON

UNDERGROUND CABLE FAULT DISTANCE

LOCATOR Submitted in the partial fulfillment for the award of the degree of

Bachelor of Engineering

in

Electronics and Communication Engineering By

Saranya Suresh (1NH12EC094)

Ranjitha.N (1NH12EC745)

Shilpa.V (1NH12EC755)

UNDER THE GUIDANCE OF Ms.Simi Ranjith

Asst. Professor,

ECE Dept, NHCE

Bangalore

Department of Electronics & Communication Engineering,

New Horizon College of Engineering, Bengaluru -560103, Karnataka.

2015-16

(i)

ACKNOWLEDGEMENT

The satisfaction that accompanies the successful completion of any task would be incomplete

without due reverence given to those who made it possible, whose constant guidance and

encouragement crowned our efforts with success.

Firstly we would like to express thanks to our college which has given us this opportunity to

work on this project.

We convey our sincere gratitude to Dr Manjunatha, Principal, NHCE, Bangalore for

facilities provided in college and for the support in numerous ways.

We remain indebted to Dr Sanjay Jain, HOD, Department of E&C, NHCE for providing us

permission to take up the project work.

We would like to express our profound gratitude to our internal guide Ms Simi Ranjith

Assistant Professor, Department of E&C, NHCE.

We would like to express our deepest sense of gratitude to our parents and friends who have

been a great source of moral support, courage, for giving us a helping hand and making us go

smiles with their lovable presence during our tough times and relieving us from stress

throughout our project endeavour.

We also thank our teaching and non-teaching staff members of Department of E&C, NHCE.

ABSTRACT

The aim of this project is to determine the distance of underground cable fault from base station

in kilometers. A constant current source feeds a known current into the wire under test (WUT).

The voltage drop across the WUT is measured using the ADC. A short circuit is detected based

on this difference voltage across the WUT. In case of a short circuit the length from the base

station is calculated and displayed locally as well as informed to the user/admin through a SMS

using a GSM modem. The length and the voltage across the WUT is also simultaneously

uploaded to a ThingSpeak channel and if necessary further analysis can be done using MATLAB

and can also be displayed using a user friendly UI.

TABLE OF CONTENTS

ACKNOWLEDGEMENT

ABSTRACT

CHAPTER 1: INTRODUCTION 1

1.1 Brief description 1

1.2 Types of faults 2

1.3 Advantages 2

1.4 Disadvantages 2

CHAPTER 2: LITERATURE SURVEY 3

CHAPTER 3: HARDWARE DESIGN 5

3.1 Block diagram 5

3.2 Introduction of Arduino 6

3.2.1 Advantages of arduino 7

3.2.2 Features of ATMEGA328 8

3.2.3 Pin configuration 9

3.2.4 Pin details 9

3.3 Power supply 10

3.4 Voltage regulator 10

3.5 Constant current source 11

3.6 Short circuit sensing element 13

3.7 LCD 15

3.7.1 Interfacing of LCD 17

3.8 GSM 17

3.8.1 General commands of GSM 18

3.8.2 HTTP commands 21

CHAPTER 4 : SOFTWARE IMPLEMENTATION 25

4.1 Initialization steps 25

4.1.1 Steps to download the program 26

4.2 Steps to post the data 28

CHAPTER 5 : HARDWARE IMPLEMENTATION 29

CHAPTER 6: RESULTS 30

6.1 Snapshot 30

6.2 Flowchart 31

CHAPTER 7: CONCLUSION & FUTURE SCOPE 36

APPENDIX 37

U N D E R G R O U N D C A B L E F A U L T D I S T A N C E L O C A T O R P a g e 1

Dept. of E&C ,NHCE 2015-16

CHAPTER 1

INTRODUCTION

1.1Brief description

More than 3 million miles of electrical cables are strung overhead across the

country. Add to that at least 180 million telephone and cable TV lines, and it’s no wonder

hurricanes, tornadoes, fires and ice storms are wreaking havoc on the electrical systems each

year, causing utility outages that last days, weeks and longer. Power outages over extended

periods present major health and safety concerns and economic losses. Concerns about the

reliability of overhead lines, increases in their maintenance and operating costs, and issues of

public safety and quality-of-life are leading more and more utilities and municipalities to the

realization that converting overhead distribution lines to underground is the best way to provide

high-quality service to their customers. For utility companies, undergrounding provides potential

benefits through reduced operations and maintenance (O&M) costs, reduced tree trimming costs,

less storm damage and reduced loss of day-to-day electricity sales when customers lose power

after storms. Creative funding options are often available to make the goal of undergrounding a

reality. The underground cable system is very important for distribution especially in

metropolitan cities, airports and defense service. Now the world is become digitalized so the

project is intended to detect the location of fault in digital way. The underground cable system is

more common practice followed in many urban areas. While fault occurs for some reason, at that

time the repairing process related to that particular cable is difficult due to not knowing the exact

location of cable fault.

Fault in cable is represented as:

• Any defect,

• Inconsistency,

• Weakness or non-homogeneity that affect performance of cable .

• Current is diverted from the intended path .

• Caused by breaking of conductor& failure of insulation

1.2TYPES OF FAULT IN UNDERGROUND CABLES

The most common types of fault that occur in underground cables are,



1. Short circuit fault.

2. Open circuit fault.

3. Earth fault.

1.2.1. Short-circuit fault

When two conductors of a multi core cable come in electrical contact with each other due

to insulation failure, it is so called as short-circuit fault.

1.2.2. Open circuit fault

When there is a break in the conductor of a cable, it is called open-circuit fault. The open-circuit

fault can check by a megger.

1.2.3. Earth fault When the conductor of a cable comes in contact with earth, it is called earth fault or ground fault.

1.3ADVANTAGES

Easy to detect the Cable fault location instruments

Systems are applicable to all types of cables ranging from 1 kV to 500 kV

Less maintenance

Less faults

Higher efficiency

1.4 DISADVANTAGES

• Cost, must consider life time costs not just initial

• Cost differential decreasing with time

• Cost of losses (30-60% less than OH), maintenance and repair

• Fault location instantaneous, can have longer repair time

• Undergrounding all of the lines would increase the cost of electricity by 16%



CHAPTER 2

LITERATURE SURVEY

Finding the location of an underground cable fault doesn’t have to be like finding a needle in a

haystack. The common methods of locating faults are

2.1 Sectionalizing: This procedure risks reducing cable reliability, because it depends on

physically cutting and splicing the cable. Dividing the cable into successively smaller sections

and measuring both ways with an ohmmeter or high-voltage insulation resistance (IR) tester

enable to narrow down search for a fault. This laborious procedure normally involves repeated

cable excavation.

2. 2 Time domain reflectometry (TDR):The TDR sends a low-energy signal through the

cable, causing no insulation degradation. A theoretically perfect cable returns that signal in a

known time and in a known profile. Impedance variations in a “real-world” cable alter both the

time and profile, which the TDR screen or printout graphically represents. One weakness of TDR

is that it does not pinpoint faults

2.3 Murray loop test: It is a bridge circuit used for locating faults in underground or

underwater cables. It uses the principle used in potentiometer experiment. One end of the

faulted cable is connected through a pair of resistors to the voltage source. Also a null detector

is connected. The other end of the cable is shorted. The bridge is brought to balance by

changing the value of RB.

In above figure, Rc is proportional to (l+ (l-x)) and RD is proportional to l.

Therefore



RA/RB=r=RC/RD = (2l-x)/x (1)

And hence

x= 2l/(r-1) (2)

Where l is the length on each segment of wire, r is the ratio RA/RB and x is the length of faulty

segment.

The main disadvantage of this method assumes that only a single fault exists, a low resistance

when compared with UG cable resistance and cable conductors have uniform resistance per unit

length

2.4 Varley loop test: If the fault resistance is high , the sensitivity in Murray bridge is

reduced and Varely oop may be more suitable but only a single fault exists. Except that here the

ratio arms are fixed and a variable resistance is connected to the test end of the faulty cable.

The drawbacks of the above methods can be overcome to certain extent by this method in which

the concept of OHM’s law is applied.



CHAPTER 3

HARDWARE DESIGN

3.1 Block Diagram

Fig.3.1.1.Block Diagram

Components:

1) Arduino

2) Power supply

3) Voltage regulator

4) Constant current source

5) Short circuit sensing element

6) LCD display

7) GSM



3.2 ARDUINO

The Arduino Uno is a microcontroller board based on the ATmega328 .It has 14 digital

input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz ceramic

resonator, a USB connection, a power jack, an ICSP header, and a reset button. It contains

everything needed to support the microcontroller; simply connect it to a computer with a USB

cable or power it with a AC-to-DC adapter or battery to get started.

The Uno differs from all preceding boards in that it does not use the FTDI USB-to-serial driver

chip. Instead, it features the Atmega328P programmed as a USB-to-serial converter.

Fig3.1.2 Arduino Atmega328P

Summary

Microcontroller

ATmega328

Operating Voltage 5V

Input Voltage 7-12V

(recommended)

Input Voltage 6-20V (limits)



Digital I/O Pins 14 (of which 6

provide PWM

output)

Analog Input Pins 6

DC Current per I/O

Pin

40 mA

DC Current for

3.3V Pin

50 mA

Flash Memory 32 KB

(ATmega328) of

which 0.5 KB used

by bootloader

SRAM 2 KB (ATmega328)

EEPROM 1 KB (ATmega328)

Clock Speed 16 MHz

3.2.1 ADVANTAGES OF ARDUINO

Inexpensive - Arduino boards are relatively inexpensive compared to other

microcontroller platforms.

Cross-platform - The Arduino software runs on Windows, Macintosh OSX, and Linux

operating systems. Most microcontroller systems are limited to Windows.

Simple, clear programming environment - The Arduino programming environment is

easy-to-use for beginners, yet flexible enough for advanced users to take advantage of as

well.

Open source and extensible software - The Arduino software is published as open source

tools, available for extension by experienced programmers.

Open source and extensible hardware - The Arduino is based on Atmel's ATMEGA8 and

ATMEGA168 microcontrollers.



3.2.2 ATMEGA328 FEATURES

The Atmega328 is a very popular microcontroller chip produced by Atmel. It is an 8-bit

microcontroller that has 32K of flash memory, 1K of EEPROM, and 2K of internal SRAM.

The Atmega328 is one of the microcontroller chips that are used with the popular Arduino

Duemilanove boards. The Arduino Duemilanove board comes with either 1 of 2 microcontroller

chips, the Atmega168 or the Atmega328. Unlike the Atmega168 which has 16K of flash program

memory and 512 bytes of internal SRAM, the Atmega328 has 32K of flash program memory and

2K of Internal SRAM. The Atmega328 is a low-power chip, so it only needs between 1.8-5.5V

of power to operate.

3.2.2 PIN CONFIGURATION

Fig.3.2.2.1 Pin mapping of ATMEGA328



3.2.3 PIN DETAILS

The Atmega328 has 28 pins.

It has 14 digital I/O pins, of which 6 can be used as PWM outputs and 6 analog input

pins.

2 of the pins are for the crystal oscillator. The chip needs power so 2 of the pins, Vcc and

GND, provide it power so that it can operate.

The Atmega328 chip has an analog-to-digital converter (ADC) inside of it.

The ADC has 3 pins set aside for it to function- AVCC, AREF, and GND.

AVCC is the power supply, positive voltage, that for the ADC.

GND is the power supply ground.

AREF is the reference voltage that the ADC uses to convert an analog signal to its

corresponding digital value.Since the ADC for the Atmega328 is a 10-bit ADC, meaning

it produces a 10-bit digital value, value.

The last pin is the RESET pin. This allows a program to be rerun and start over.

Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL serial data.

External Interrupts: 2 and 3 are configured to trigger an interrupt on a low value, a rising

or falling edge, or a change in value.

PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the analogWrite() function.



3.3 POWER SUPPLY

Fig.3.3.1.Power Supply

An AC voltage of 230v is step down to 5v using a step down transformer. Ac voltage is

converted into dc voltage using a bridge rectifier. Capacitors are used to remove the ripple in the

output.

A voltage regulator is used to maintain the constant output voltage 5v.

3.4 VOLTAGE REGULATOR

IC 7805 is a 5V Voltage Regulator that restricts the voltage output to 5V and draws

5V regulated power supply. It comes with provision to add heatsink .The maximum value for

input to the voltage regulator is 35V. It can provide a constant steady voltage flow of 5V for

higher voltage input till the threshold limit of 35V. If the voltage is near to 7.5V then it does not

produce any heat and hence no need for heatsink. If the voltage input is more, then excess

electricity is liberated as heat from 7805 .It regulates a steady output of 5V if the input voltage is

in rage of 7.2V to 35V. Hence to avoid power loss try to maintain the input to 7.2V. In some

circuitry voltage fluctuation is fatal for such situation to ensure constant voltage IC 7805

Voltage Regulator is used.



Fig3.4.1Lm7805voltageregulator

Fig 3.4.2 characteristics of LM7805

3.5 CONSTANT CURRENT SOURCE

A current source is an electronic circuit that delivers or absorbs an electric current which is

independent of the voltage across it.A current source is the dual of a voltage source.

Transistor active constant current source basics

The simple use of a transistor enables a far more effective current source to be made.

https://en.wikipedia.org/wiki/Electronic_circuit

https://en.wikipedia.org/wiki/Electric_current

https://en.wikipedia.org/wiki/Duality_(electrical_circuits)

https://en.wikipedia.org/wiki/Voltage_source



The current source operates because of the fact that the collector current in a transistor circuit is

Β times the base current. This is independent of the collector voltage, provided that there is

sufficient voltage to drive the current through the load device in the collector.

Fig.3.5.1Basic transistor constant current circuit

In this circuit, the collector current is Β times the base current. Normally Β is large and therefore

it can be assumed that the emitter current which is (Β + 1) times the base current and the

collector current which is Β times the base current are the same.

In view of this it is a simple matter to design the circuit for a given current.

By setting the resistors R1 and R2 it is possible to set the base voltage. The emitter voltage will

be 0.6 volts less, assuming a silicon transistor. By knowing the emitter voltage, it is possible to

calculate the emitter current from a simple knowledge of Ohms law.



Simple stabilised active current source circuit

In order to remove any fluctuations in current arising from changes in supply voltage it is a

simple matter to add some regulation to the basic circuit. This is achieved by replacing R2 with a

Zener or voltage reference diode.

Fig3.5.2Simple regulated transistor active constant current circuit

The same equations apply as before, but the only difference is that the base voltage is held at a

more constant level as a result of the presence of the Zener, voltage reference diode.

3.6 SHORT CIRCUIT SENSING ELEMENT

Nichrome is used as a cable which carries the current.

Nichrome (NiCr, nickel-chrome, chrome-nickel, etc.) generally refers to

any alloy of nickel, chromium, and often iron and/or other elements or substances. Nichrome

alloys are typically used in resistance wire. They are also used in some dental

restorations (fillings) and in other applications.

The properties of nichrome vary depending on its alloy. Figures given are representative of

typical material and are accurate to expressed significant figures. Any variations are due to

different percentages of nickel or chromium.

https://en.wikipedia.org/wiki/Nickel


https://en.wikipedia.org/wiki/Alloy


https://en.wikipedia.org/wiki/Chromium

https://en.wikipedia.org/wiki/Iron

https://en.wikipedia.org/wiki/Chemical_element

https://en.wikipedia.org/wiki/Resistance_wire

https://en.wikipedia.org/wiki/Dental_restoration

https://en.wikipedia.org/wiki/Dental_restoration



Material property Value Unit

Modulus of elasticity 2.2 × 1011 Pa

Density 8400 kg·m−3

Melting point 1400 °C

Electrical resistivity at room temperature (1.0—1.5) × 10−6 Ω·m

Specific heat 450 J·kg−1·K−1

Thermal conductivity 11.3 W·m−1·K−1

Thermal expansion 14 × 10−6 K−1

Standard ambient temperature and pressure

Fig 3.6.1 characteristic of Nichrome

https://en.wikipedia.org/wiki/Modulus_of_elasticity

https://en.wikipedia.org/wiki/Density

https://en.wikipedia.org/wiki/Melting_point

https://en.wikipedia.org/wiki/Celsius

https://en.wikipedia.org/wiki/Resistivity

https://en.wikipedia.org/wiki/Specific_heat

https://en.wikipedia.org/wiki/Kelvin

https://en.wikipedia.org/wiki/Thermal_conductivity

https://en.wikipedia.org/wiki/Thermal_expansion

https://en.wikipedia.org/wiki/Standard_ambient_temperature_and_pressure



3.7 LCD

The figure below shows LCD which is a liquid crystal display is a low cost device

capable of displaying text and images. LCD are, extremely common in embedded

system since such system often do not have video monitor like those that come

standard with desktop system. LCD can be found in numerous common devices

like watches fax and copy machines and calculators .The basic principle of one type

of LCD, a reflective LCD works as follows:

First incoming light passes through a polarizing plate

Polarized light encounters liquid crystal material if we excite a region of the

material

We cause the material‘s molecules to align, which in turns causes the polarized

light to pass through hits a mirror and reflects back, so the excited region appears to

light up.

Another type of LCD, an absorption LCD, works similarly, but uses a black

surface instead of a mirror. The surface below the exited region absorbs light, thus

appearing darker than the other regions.

An LCD driver converts these inputs to the electrical signals necessary to

excite the appropriate LCD segments. A dot matrix LCD consists of the matrix of

dots that can display alphanumerical characters (letters and digits) as well as other

symbol. A common dot matrix LCD has five columns and eight rows of dots for

one character .An LCD driver converts input data into the appropriate electrical

signal necessary to excite the appropriate LCD dots.

Each type of LCD may be able to display multiple characters. In addition, each

character may be displayed in normal or inverted display fashion. The LCD may

permit a character to be blinking indicating the current character. Such functionality

is difficult to implement for us to implement through software, thus we use an LCD

controllers to provide us with a simple interface to an LCD, perhaps eight inputs

and pulse the enable. This byte may be control word, which instructs the LCD



controller to initialize the LCD, clear display; select the position of the cursor

brighten the display, and so on. Alternatively, this byte may be a data word, such as

an ASCII character, instructing the LCD to display the character at the currently–

selected display position.

A 16x2 LCD means it can display 16 characters per line and there are 2 such lines.

In this LCD each character is displayed in 5x7 pixel matrix. This LCD has two

registers, namely, Command and Data.The command register stores the command

instructions given to the LCD. A command is an instruction given to LCD to do a

predefined task like initializing it, clearing its screen setting the cursor position,

controlling display etc. The data register stores the data to be displayed on the LCD.

The data is the ASCII value of the character to be displayed on the LCD.

Fig 3.7.1 16x2 LCD



3.7.1 Interfacing LCD

Fig 3.7.1 16x2 LCD Interfacing

The LCD LM018L has 16 pin connections as shown in the above figure. Pin1, Pin3 and

Pin16 are all grounded. Pin2 and Pin15 are given to +5V. We can use a potentiometer or

variable resistor between Pin1 and Pin3 for getting different contrast. Pin15 and Pin16 are

used for back light. Pin7 to 14 are used as data lines. Pin4 is rs, to data input we make rs=1

and to instruction code input we make rs=0. Pin5 is made 0 (gnd) to data write and made 1

(+5V) data read. Pin6 is enable, it is made high to enable the LCD.

3.8 GSM (GLOBAL SYSTEM FOR MOBILE

COMMUNICATION)

The SIM900 is a complete Quad-band GSM/GPRS solution in a SMT

module which can be embedded in the customer applications.

General features

Quad-Band 850/ 900/ 1800/ 1900 MHz ”

GPRS multi-slot class 10/8

GPRS mobile station class B



Compliant to GSM phase 2/2+

– Class 4 (2 W @850/ 900 MHz)

– Class 1 (1 W @ 1800/1900MHz)

Control via AT commands (GSM 07.07 ,07.05 and SIMCOM

enhanced AT Commands)

SIM application toolkit

Supply voltage range 3.4 ... 4.5 V

Low power consumption

Operation temperature: -30 °C to +80 °C

The "AT" or "at" prefix must be set at the beginning of each command

line. To terminate a command line enter <CR>. Commands are usually

followed by a response that

includes.”<CR><LF><response><CR><LF>”. Throughout this

document, only the responses are presented, <CR><LF> are omitted

intentionally.

Global system for mobile communication (GSM) is a globally accepted standard

for digital cellular communication. GSM is the name of a standardization group

established in 1982 to create a common European mobile telephone standard that

would formulate specifications for a pan-European mobile cellular radio system

operating at 900 MHz. It is estimated that many countries outside of Europe will

join the GSM partnership.

3.8.1 General commands for GSM

1. Manufacturer identification +CGMI

Description:

This command gives the manufacturer identification.

Syntax:

Command syntax: AT+CGMI



2. New message indication +CNMI

Description:

This command selects the procedure for message reception from the network.

Syntax :

Command syntax : AT+CNMI=<mode>,<mt>,<bm>,<ds>,<bfr>

3. Send message +CMGS

Description :



The <address> field is the address of the terminal to which the message is sent. To send the

message, simply type, <ctrl-Z> character (ASCII 26). The text can contain all existing

characters except <ctrl-Z> and <ESC> (ASCII 27). This command can be aborted using

the <ESC> character when entering text. In PDU mode, only hexadecimal characters are

used (‘0’…’9’,’A’…’F’).

Syntax :

Command syntax in PDU mode :

AT+CMGS= <length><CR>

PDU is entered <ctrl-Z / ESC >

FLOW CHART

GSM_Send_SMS

Fig 3.8.1: Flow chart of GSM send SMS

AT+CMGS= command transmitted

serially to GSM module through UART0

0x22(ASCII value of “)

Mobile number

0x22(ASCII value of “)

Message

0x0D(ASCII value of carriage return)

0x1A(ASCII value of cntrl+z to send

message)



3.8.2 HTTP COMMANDS

In computing, POST is one of many request methods supported by the HTTP protocol used by

the World Wide Web. By design, the POST request method requests that a web server accepts

and stores the data enclosed in the body of the request message.[1] It is often used when

uploading a file or submitting a completed web form.

In contrast, the HTTP GET request method is designed to retrieve information from the server.

As part of a GET request, some data can be passed within the URL's query string.

AT COMMANDS WITH RESPONSE

1. AT+SAPBR

2. AT+HTTPINIT

3. AT+HTTPTERM

https://en.wikipedia.org/wiki/HTTP#Request_methods

https://en.wikipedia.org/wiki/HTTP

https://en.wikipedia.org/wiki/World_Wide_Web

https://en.wikipedia.org/wiki/Web_server

https://en.wikipedia.org/wiki/POST_(HTTP)#cite_note-RFC_def-1

https://en.wikipedia.org/wiki/Form_(HTML)

https://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol#Request_methods

https://en.wikipedia.org/wiki/Query_string



4. AT+HTTPDATA

5. AT+HTTPACTION



6. AT+HTTPREAD

AT COMMANDS WITH RESPONSE

AT+SAPBR=3,1,"Contype","GPRS"

OK

AT+SAPBR=3,1,"APN","WWW"

OK

AT+SAPBR=1,1

OK

AT+SAPBR=2,1

+SAPBR: 1,1

AT+HTTPINIT

OK

AT+HTTPPARA="CID",1

OK

AT+HTTPPARA="URL","http://api.thingspeak.com/update"

OK

AT+HTTPDATA=33,10000



DOWNLOAD

key=D9R6K3Y1NNMNZPCD&field1=3300

OK

AT+HTTPACTION=1

OK

+HTTPACTION:1,200,<no_of_bytes>

AT+HTTPTERM



CHAPTER 4

SOFTWARE IMPLEMENTATION

STEP 1:Download and install arduino



STEP 2: Select the arduino uno board from tools

STEP 3: Select COM port



STEP 4: Compile the code and upload to aurduino



4.2 TO POST THE DATA TO THINGSPEAK CHANNEL

STEP1: Create a channel in ThingSpeak website

STEP 2: Choose the fields(distance and voltage)



CHAPTER 5

HARDWARE IMPLEMENTATION

Fig 5.1.1 underground cable fault detector

The 12v supply is step down to 5v and constant voltage is obtained using a voltage

regulator LM7805.

A Constant current source is used to produce a 100mA constant current which

drives the WUT.

A change in the voltage is read by the ADC(A0 and A1 pins of ARDUINO)

Necessary calculations are performed by ARDUINO

The distance at which the short circuit occurs is displayed on the LCD.

The SMS is sent to the assigned number and the same is posted onto the thingspeak

channel.



CHAPTER 6

RESULTS

• The snapshot below shows that the WUT is shorted at 31.27cm which is displayed

on LCD.

The same is sent as a SMS to assigned number and it is posted in the thingSpeak

channel.

Fig 6.1.1 short distance displayed on LCD



Fig 6.1.2The short distance is displayed on thingspeak channel



Fig 6.1.3 message sent to mobile



6.2 FLOWCHART



CHAPTER 7

CONCLUSION Underground distribution systems are characterized with their unique features that usually raise

their own complexities regarding protection functions. For fault location computation, in

particular, the considerable charging currents play a basic role affecting most of the known

single-end computational fault location schemes. The proposed algorithm shows a high

performance for locating faults in underground distribution feeders. Its basic core depends on

calculating the corresponding fault location with the apparent voltage approach. All test results

show a remarkable performance for locating faults in cable segments even with

high values of fault resistances.

FUTURE SCOPE

In this project we detect only the location of short circuit fault in underground cable line, but we

also detect the location of open circuit fault, to detect the open circuit fault capacitor is used in ac

circuit which measure the change in impedance & calculate the distance of fault.



REFERENCES

1) DEVELOPMENT OF PROTOTYPE UNDERGROUND CABLE FAULT

DETECTOR- Department of Electronics and Communication Engineering.

2) UNDERGROUND CABLE FAULT DISTANCE LOCATOR -

INTERNATIONAL JOURNAL OF INNOVATIONS IN ENGINEERING

RESEARCH AND TECHNOLOGY [IJIERT] ISSN: 2394-3696,VOLUME 2,

ISSUE 4APR.-2015

3) AN ACCURATE FAULT LOCATOR FOR UNDERGROUND

4) DISTRIBUTION NETWORKS USING MODIFIED APPARENT-IMPEDANCE

CALCULATION- Electrical Engineering Dept., Faculty of Engineering,

Menoufiya University, Shebin El-Kom,Egypt

5) Tarlochan S. Sidhu, Zhihan Xu, “Detection of Incipient Faults in Distribution

Underground Cables”, IEEE Transactions on Power Delivery, Vol. 25, NO. 3,

JULY 2010.

6) Md. Fakhrul Islam, Amanullah M T Oo, Salahuddin. A. Azad1 , “Locating

Underground Cable Faults: A Review and Guideline for New Development” ,

2013 IEEE

7) http://www.scribd.com

8) http://ecmweb.com/content/locating-underground-cable

http://www.scribd.com/



APPENDIX

* LCD RS pin to digital pin 12

* LCD R/W pin to ground

* LCD Enable pin to digital pin 11

* LCD D4 pin to digital pin 5




* LCD VSS pin to ground

* LCD VCC pin to 5V

* Serial port for GSM modem

* GSM modem RxD - pin 9

* GSM modem TxD - pin 8

#define Vcc 4970.0

#define Isupp 100.0 //supply current to sensor in mA

#define HTTP_DOWNLOAD_LATENCY 5000

#define HTTPDATA_LEN 60

#define WRITEAPIKEY "5LE4M38C1R5KC169"

#define Diag Serial

#define PHONE_NUMBER "\"+917411850476\""

#define ADC_SD_DEVIATION 5

#define ADC_SAMP_SIZE 10

float V1, V2, NoShrtVtg, RT ;



#include <SoftwareSerial.h>

#include <LiquidCrystal.h>

char* floatToString(char * outstr, float value, int places, int minwidth, bool rightjustify);

//create a SW serial object for comm. with GSM modem

SoftwareSerial GSM_PORT(8, 9); // RX, TX

// initialize the library with the numbers of the interface pins

LiquidCrystal LCD(12, 11, 5, 4, 3, 2);

// the setup routine runs once when you press reset:

int IsModemAlive( void )

{

if( SendCommand("AT", "OK", 200) )

return 1 ;

return 0 ;

}

int IsSIMRegstrd( void )

{

int count = 5 ;

do

{

if( SendCommand("AT+CPIN?", "+CPIN: READY", 200) )

if( SendCommand("AT+CREG?", "+CREG: 0,1", 200) )

return 1 ;

else

count-- ;

else



count-- ;

}while( count>0 ) ;

return 0 ;

}

int SendCommand(char *Cmd, char *PosResp, int timeout_ms )

{

char RxBuf[50], c ;

int len ;

long int startTime ;

int stCpy ;

//send the command

GSM_PORT.println(Cmd);

Diag.print(Cmd) ;

GSM_PORT.flush();

delay(200);

startTime = millis() ;

len = 0 ;

stCpy = 0 ;

do

{

while( GSM_PORT.available()>0 )

{

c = GSM_PORT.read() ;

if( !stCpy && c==PosResp[0] )

stCpy = 1 ;



if( stCpy == 1 )

{

RxBuf[len%(sizeof(RxBuf)/sizeof(RxBuf[0]))] = c ;

len=len+1 ;

}

}

}while( !strstr( RxBuf, PosResp) && !strstr( RxBuf, "ERROR") && ((millis()-

startTime)<timeout_ms) ) ;

if( strstr( RxBuf, PosResp) )

{

Diag.println(F(" ---- + resp"));

return 1;

}

else

{

Diag.println(F(" ---- - resp"));

return 0;

}

}

int SendSMS(char number[], float x)

{

char command[30]= "AT+CMGS=", msg[50]="short ckt found at ", x_str[10] ;

char ctrl_z[2]={26,'\0'} ;



//create diagnostic message to be sent to user

ftoa(x_str, x, 1, 0, false);

strcat(msg,x_str);

strcat(msg," cm");

strcat(msg,(char*)ctrl_z);

strcat( command, number );

delay(500);

if( SendCommand("AT+CMGF=1","OK",200) )

if( SendCommand(command,">", 400) )

if( SendCommand(msg,"+CMGS", 15000) )

return 1;

return 0 ;

}

char* ftoa(char * outstr, float value, int places, int minwidth, bool rightjustify) {

//char * floatToString(char * outstr, float value, int places, int minwidth=0, bool

rightjustify=false) {

// this is used to write a float value to string, outstr. oustr is also the return value.

int digit;

float tens = 0.1;



int tenscount = 0;

int i;

float tempfloat = value;

int c = 0;

int charcount = 1;

int extra = 0;

// make sure we round properly. this could use pow from <math.h>, but doesn't seem worth the

import

// if this rounding step isn't here, the value 54.321 prints as 54.3209

// calculate rounding term d: 0.5/pow(10,places)

float d = 0.5;

if (value < 0)

d *= -1.0;

// divide by ten for each decimal place

for (i = 0; i < places; i++)

d/= 10.0;

// this small addition, combined with truncation will round our values properly

tempfloat += d;

// first get value tens to be the large power of ten less than value

if (value < 0)

tempfloat *= -1.0;

while ((tens * 10.0) <= tempfloat) {

tens *= 10.0;



tenscount += 1;

}

if (tenscount > 0)

charcount += tenscount;

else

charcount += 1;

if (value < 0)

charcount += 1;

charcount += 1 + places;

minwidth += 1; // both count the null final character

if (minwidth > charcount){

extra = minwidth - charcount;

charcount = minwidth;

}

if (extra > 0 and rightjustify) {

for (int i = 0; i< extra; i++) {

outstr[c++] = ' ';

}

}

// write out the negative if needed



if (value < 0)

outstr[c++] = '-';

if (tenscount == 0)

outstr[c++] = '0';

for (i=0; i< tenscount; i++) {

digit = (int) (tempfloat/tens);

itoa(digit, &outstr[c++], 10);

tempfloat = tempfloat - ((float)digit * tens);

tens /= 10.0;

}

// if no places after decimal, stop now and return

// otherwise, write the point and continue on

if (places > 0)

outstr[c++] = '.';

// now write out each decimal place by shifting digits one by one into the ones place and

writing the truncated value

for (i = 0; i < places; i++) {

tempfloat *= 10.0;

digit = (int) tempfloat;



itoa(digit, &outstr[c++], 10);

// once written, subtract off that digit

tempfloat = tempfloat - (float) digit;

}

if (extra > 0 and not rightjustify) {

for (int i = 0; i< extra; i++) {

outstr[c++] = ' ';

}

}

outstr[c++] = '\0';

return(outstr);

}

int updateTSField(char * key, float len, float voltage)

{

char httpdata[HTTPDATA_LEN]="key=", buf[5] ;

strcat(httpdata, key);

strcat(httpdata,"&field1");

strcat(httpdata,"=");

strcat(httpdata,ftoa(buf, len, 2, 0, false));

strcat(httpdata,"&field2");

strcat(httpdata,"=");



strcat(httpdata,ftoa(buf, voltage, 2, 0, false));

if( httpPOST( httpdata ) )

return 1 ;

else

return 0 ;

}

int httpPOST( char *data )

{

char httpdata_cmd[30]="AT+HTTPDATA=" ;

char buf[10] ;

int state ;

//setup bearer settings for GPRS

if( !setupGPRS() )

return 0;

//construct the AT+HTTPDATA=<no_of_bytes_for_download>,<latency_time>

strcat(httpdata_cmd, itoa(strlen(data), buf, 10));

strcat(httpdata_cmd, ",");

strcat(httpdata_cmd, itoa(HTTP_DOWNLOAD_LATENCY, buf, 10));

state = 0 ;

//continue with HTTP POST



if( SendCommand( "AT+HTTPINIT", "OK", 200) )

if( SendCommand( "AT+HTTPPARA=\"CID\",1", "OK", 200) )

if( SendCommand( "AT+HTTPPARA=\"URL\",\"http://api.thingspeak.com/update\"",

"OK", 500) )

if( SendCommand( httpdata_cmd, "DOWNLOAD", 800) )

if( SendCommand( data, "OK", 200) )

if( SendCommand( "AT+HTTPACTION=1", "+HTTPACTION:1,200", 4000) )

state = 1 ;

else

SendCommand( "AT+HTTPREAD", "OK", 3000);

SendCommand( "AT+HTTPTERM", "OK", 200);

return(state) ;

}

int setupGPRS( void )

{

long int startTime = millis() ;

do

{

if( SendCommand( "AT+SAPBR=2,1", "+SAPBR: 1,1,", 200) )

break ;

if( !SendCommand("AT+CGATT?","+CGATT: 1", 200) )



SendCommand("AT+CGATT=1","OK",200);

if( SendCommand( "AT+SAPBR=3,1,\"Contype\",\"GPRS\"", "OK", 200) )

if( !SendCommand( "AT+SAPBR=1,1", "OK", 2000) )

if( SendCommand( "AT+SAPBR=2,1", "+SAPBR: 1,1", 200) )

break ;

}while( (millis()-startTime)<10000 ) ; //try to get a GPRS context for 10s

if( (millis()-startTime)<10000 )

return 1 ;

else

return 0 ;

}

void setup() {

// initialize serial communication at 115200 bits per second:

Diag.begin(115200);

//initialise a sw serial port to communicate with GSM modem

GSM_PORT.begin(9600);

// set up the LCD's number of columns and rows:

LCD.begin(16, 2);



V1 = ((float)analogRead(A0) * (Vcc/1023)); //in mV

V2 = ((float)analogRead(A1) * (Vcc/1023)); //in mV

RT = (V1-V2)/Isupp ;

NoShrtVtg = V2 ;

String V1_str = "V1 = " + String(V1) + " mV" ;

String V2_str = "V2 = " + String(V2) + " mV" ;

String RT_str = "RT = " + String(RT) + " ohms" ;

Diag.println(V1_str);


Diag.println(RT_str);

LCD.clear();

LCD.print(V1_str);

LCD.setCursor(0,1);

LCD.print(V2_str);

delay(2000);

LCD.clear();

LCD.print(RT_str);

delay(2000);

LCD.clear();

LCD.print( "waiting 4 GSM" );



do

{

Diag.println( "Waiting for GSM modem to initialise" ) ;

}while( !IsModemAlive() );

do

{

Diag.println( "Checking SIM" ) ;

}while( !IsSIMRegstrd() );

}

// the loop routine runs over and over again forever:

void loop()

{

float R ;

float len ;

String res ;

int i, stStab ;

long int startTime ;

float adcVtg[ADC_SAMP_SIZE], mean, sum , sd ;

String V1_str, V2_str, LCDMsg ;

while( 1 )

{

V1 = analogRead(A0) * (Vcc/1023) ;



V2 = analogRead(A1) * (Vcc/1023) ;

V1_str = "V1 = " + String(V1) + " mV" ;

V2_str = "V2 = " + String(V2) + " mV" ;



if( V2 > NoShrtVtg )

{

startTime = millis() ;

LCD.clear();

LCD.print( F("stab check") );

Diag.println( F("checking voltage stability") );

//calculate the deviation of the voltage

//this is to prevent false positives

stStab = 0 ;

do

{

for( i=0, sum=0 ; i<ADC_SAMP_SIZE ; i++ )

{

adcVtg[i] = analogRead(A1) * (Vcc/1023) ;

//Diag.println(adcVtg[i]);



if( adcVtg[i] > NoShrtVtg )

sum+=adcVtg[i] ;

else

break ;

delay(50);

}

if( i==ADC_SAMP_SIZE )

{

mean = sum/ADC_SAMP_SIZE ;

for( i=0, sum=0 ; i<ADC_SAMP_SIZE ; i++ )

sum += pow((adcVtg[i]-mean), 2);

sd = sqrt((sum/ADC_SAMP_SIZE));

Diag.print( "vtg deviation = " );

Diag.println(sd);

if( sd > ADC_SD_DEVIATION )

stStab = 0 ;

else

stStab = 1 ; //read voltage is stable, proceed with further calculation

}

else



break ;

}while( stStab!=1 && ((millis()-startTime)< 5000) );

if( stStab==1 )

{

R = (V1 - mean) / Isupp ;

len = (R * 100.0)/RT ;

res="R="+String(R)+" len = " + String(len) ;

Diag.println(res);

//create diagnostic message to be sent to user

LCDMsg = "short - " + String(len) + "cm";

//update to ThingSpeak channel

LCD.clear();

LCD.print(LCDMsg);

LCD.setCursor(0,1);

//update it to Thingspeak channel

if( !updateTSField( WRITEAPIKEY, len, (V1-V2) ) )

{

LCD.print( F("PST - F") );

Diag.println( F("POST - failed") );

}

else



{

LCD.print( F("PST - S") );

Diag.println( F("Channel post - success") );

}

//send the SMS

LCD.setCursor(8,1);

Diag.println( F("sending SMS") );

if( SendSMS(PHONE_NUMBER, len) )

{

Diag.println( F("SMS sent - success") );

LCD.print( F("SMS - S") );

}

else

{

Diag.println( F("SMS sent - failed") );

LCD.print( F("SMS - F") );

}

while(1);

}

}

else

{

LCD.clear();

LCD.print( F("No short circuit") );



}

delay(2000);

}

Diag.println( F("unreachable point") );

}

VISVESVARAYA TECHNOLOGICAL UNIVERSITY ...

Documents

Transcript of VISVESVARAYA TECHNOLOGICAL UNIVERSITY ...