Fault Location and Identification for Underground Power Cable Using Distributed Parameter Approach...

8/19/2019 Fault Location and Identification for Underground Power Cable Using Distributed Parameter Approach by Wscada

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FAULT LOCATION AND IDENTIFICATION FOR

UNDERGROUND POWER CABLE USING

DISTRIBUTED PARAMETER APPROACH BY WSCADA

A PROJECT REPORT

Submi tted by

VINOTH KUMAR.M

PUSHPARAJ.K

VELMURUGAN.V

PRABAKARAN.R

in partial f ul fi llment for the award of the degree

of

BACHELOR OF ENGINEERIN

ELECTRICAL AND ELECTRONICS ENGINEERING

APOLLO ENGINEERING COLLEGE, CHENNAI

ANNA UNIVERSITY: CHENNAI 600 025

APRIL 2013


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ANNA UNIVERSITY : CHENNAI 600 025

BONAFIDE CERTIFICATE

Certified that this project report “FAULT LOCATION AND

IDENTIFICATION FOR UNDERGROUND POWER CABLE USING

DISTRIBUTED PARAMETER APPROACH BY WSCADA”is the bonafide

work of “VINOTHKUMAR.M”who carried out the project work under my

supervision.

SIGNATURE SIGNATURE

D.RAMASUBRAMANIAN AISHWARYA.R

HEAD OF THE DEPARTMENT SUPERVISOR

DEPT. OF ELECTRICAL AND MASTER OF ENGINEERING

ELECTRONICS ENGINEERING DEPT. OF ELECTRICAL AND

APOLLO ENGINEERING COLLEGE ELECTRONICS ENGINEERING

CHENNAI-602105 APOLLO ENGINEERING COLLEGE


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TABLE OF CONTENTS

CHAPTER NO TITLE PAGE NO

ABSTRACT viii

LIST OF TABLE ix

LIST OF FIGURES x

LIST OF SYMBOLS

1 INTRODUCTION 1

1.1 GENERAL 1

1.2 NEED FOR UNDER GROUND SUSTEM 1

1.3 CABLE TYPES AND THERE CHARECTERISTICS 2

2 LITERATURE REVIEW 3

3 BLOCK DIAGRAM 5

3.1 GENERAL 5

3.2 OVER ALL BLOCK DIAGRAM 5

3.2.1ZONE-1(open/close circuit detection node) 7

3.2.2 ZONE-2(over current/low voltage detection node) 7

3.3.3 Server Monitoring Unit 8

3.3.4 Cable Faults 8

3.3.5 Zigbee 8

3.3.6 WSCADA 9

3.3.7 Sensor 9

3.3.7.1 Voltage Sensor 9


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3.3.7.2 Current Sensor 9

3.3.8 PIC Micro Controller 10

3.3.9 Liquid Crystal Display 10

3.3.10 MP LAB IDE 10

4 FAULT 11

4.1 INTRODUCTION 11

4.2 CABLE FAULT TYPES 11

4.2.1 Fault between core-core and/or core-sheath 11

4.2.2 Defects on the outer protective shield(PVC,PE) 11

4.3 CABLE FAULT LOCATION PROCEDURE 12

4.4 CABLEFAULT PRELOCATION 12

4.4.1 Impuse reflection method TDR 12

4.4.2 Muitiple impulse method(SIM/MIM) 13

4.4.3Bridge method 13

5 WSCADA 14

5.1 INTRODUCTION 14

5.2 FEATURES OF WSCADA 15

5.3 COMPONENTS OF THE SCADA SYSTEM 16

5.3.1 Master unit 16

5.3.2 Remote unit 16

5.3.3 Communication mode 16

6 ZIGBEE 18

6.1 INTRODUCTION 18

6.2 WSN CONCEPT 18

6.2.1 The main purposes of WSN deployment 19


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6.2.1.1 To Monitor 19

6.2.1.2 To Control 19

6.2.1.3 Both to monitor and to control 19

6.3 COMPARISION OF ZIGBEE AND BLUETOOTH 20

7 PIC CONTROLLER 21

7.1 INTRODUCTION 21

7.1.1 PIC (16F877) 21

7.2 FEATURES 21

7.2.1 High performance RISC CPU 21

7.2.2 Peripheral features 22

7.2.3 Analog features 22

7.2.4 Special Microcontroller features 22

7.3 CMOS TECHNOLOGY 23

7.4 DEVICE OVERVIEW 23

7.5 PINDIAGRAM 25

7.6 I/O PORTS 26

7.6.1 Port A and TRISA Resister 26

7.6.2 Port B and TRISB Resister 26

7.6.3 Port C and TRISC Resister 27

7.6.4 Port D and TRISD Resister 27

7.6.5 Port E and TRISE Resister 27

7.7 STATUS RESISTER 28

7.8MEMORY ORGANIZATOIN 30

7.8.1 Program memory organization 30

7.9 RESISTER FILE MAP 31

7.9.1 General Purpose Register 31


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8 SENSOR 32

8.1 INTRODUCTION 32

8.2 VOLTAGE SENSOR 32

8.3 CURRENT SENSOR34

9 HARTWARE IMPLEMENTATION 36

9.1 GENERAL 36

9.2 HARDWARE DESCRIPTION36

9.2.1 Circuit Description 36

9.3 OVER ALL CIRCUIT 37

9.3.1 Circuit Operation 38

9.3.2 RS232 Interfacing 38

9.4 POWER SUPPLY 39

9.4.1 Step-down transformer 40

9.4.2 Rectifier circuit 40

9.4.3 Input filter 41

9.4.4 Regulator unit 41

9.4.4.1 IC Voltage Regulators 41

9.4.5 Output filter 42

9.5 PIC CONTROLLER 43

9.5.1 Analog Inputs 43

9.5.2 Digital Signals 43

9.5.3 Clock 43

9.5.4 MCLR/VPP 44

9.5.5 TXD and RXD 44

9.5.6 Vcc and Ground 44

9.6 LIQUIT CRYSTAL DISPLAY 45


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9.6.1 44780 Background 45

9.6.2Handling the EN control line 46

9.6.3 Checking the busy status of the LCD 47

9.6.4 Initializing the LCD 48

9.6.5 Clearing the display 48

9.6.6 Writing text to the LCD 48

10 CONCLUSION 50

10.1 Future Scope 50

REFERENCE 51

APPENDIX 52

PHOTOS 62


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ABSTARCT

This project proposes an extensive fault location model for underground

power cable in distribution system using voltage and current measurements at the

sending-end. First, an equivalent circuit that models a faulted underground cable

system is analyzed using distributed parameter approach.

Then, the analysis of sequence networks in wireless sensor network is

obtained by applying the boundary conditions. This analysis is used to calculate a

fault location in single section using voltage and current measurements. The

extension to multi-section is further analyzed based on wireless distribution

systems.

This method is an iterative process to determine a faulted section from the

network.The network identity can be done by having unique MAC id provided for

the Zigbee Wireless Transceiver. Finally, the design and implementations are

evaluated with variations of fault open/close circuit and over current/voltage,

which also includes the evaluation of its robustness to load uncertainty.


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ACKNOWLEDGEMENT

Very special people have contributed significantly for this project. It would

not have been possible without the kind support and help of these individuals.

Iwould like to extend my sincere thanks to all of them.

In the deep midst pleasure and satisfaction we express our deep sense

Ofgratitude to our beloved chairman forthe keen interest and affection towards us

throughout the course

I convey my sincere thanks to V. NATARAJAN,Principal, Apollo

Engineering college for providing allfacilities to complete my work in time.

I wish to express my sincere thanks to Mr.D.RAMASUBRAMANIYAN,

M.E., (Ph.D),Head of the Department of Electrical and Electronics Engineering,

for thecontinuous help over the period of project work.

I express my deep sense of gratitude to my

guideMiss.R.AISWARYA,M.E,Assistant Professor, for her ingeniouscommitment,encouragement and highly valuable advice that she has provided over

the entirecourse of this project.

I also express my thanks to all staff members, Department of Electrical

andElectronicsEngineering and my classmates for their support and suggestions

duringthis project.


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LIST OF FIGURES

FIGURE NO TITLE PAGE NO

3.1 OVER ALL BLOCK DIAGRAM 5

3.2 ZONE-1(OPEN/CLOSE CIRCUIT DETECTION NODE) 6

3.3 ZONE-2(OVER CURRENT/LOW VOLTAGE DETECTION 6

NODE)

3.4SERVER MONITORING UNIT 7

5.1wscada 17

6.1WSN (REMOTE SENSORS MONITORING) 18

7.1PIN DIAGRAM 24

7.2STATUS REGISTER 27

7.3REGISTER FILE MAP 30

8.1VOLTAGE SENSOR 31

8.2 CURRENT SENSOR 33

9.1OVERALL CIRCUIT 36

9.2RS232 INTERFACING 37

9.3POWER SUPPLY CIRCUIT 39

9.4 LCD 49


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LIST OF TABLE

TABLE NO TITLE PAGE NO

6.1 COMPARISON OF ZIGBEE AND BLUETOOTH 19

7.1 DEVICE OVERVIEW 23

7.2 STATUS REGISTER 28


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CHAPTER 1

INTRODUCTION

1.1 GENERAL

Power supply networks are growing continuously and their reliability is

getting more important than ever.

The power supply systems are broadly classified into two categories. They

are,

I. Overhead transmission system

II. Underground transmission system

1.2 NEED FOR UNDER GROUND SYSTEM

For most of the worldwide operated low voltage and medium voltage

distribution lines underground cables have been used for many decades. During the

last years, also high voltage lines have been developed to cables.

To reduce the sensitivity of distribution networks to environmental

influences underground high voltage cables are used more and more. They are not

influenced by weather conditions, heavy rain, storm, snow and ice as well as

pollution. Cables have been in use for over 80years. The number of different

designs as well as the variety of cable types and accessories used in a cable

network is large.

The ability to determine all kind of different faults with widely different

fault characteristics is turning on the suitable measuring equipment as well as on

the operator’s skills. The right combination enables to reduce the expensive timethat is running during a cable outage to a minimum.


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1.3 CABLE TYPES AND THEIR CHARACTERISTICS

Cable types are basically defined as low-, medium- and high voltage cables.

The tendency of the last year’ s show the shifting to single-core systems as they are

lower in price, lower in weight and cheaper in regards to repair costs. Furthermore

oil impregnated or oil filled cables are used less and less, as the environmental

sustainability cannot be guaranteed. Especially in industrialized countries, these

cable types have been replaced and are no more installed.

On the other hand a high demand for maintenance of those cables is given as

the installed oil-insulated networks do show up a lifetime of 50 years and more.

Today mainly XLPE (Cross Linked Polyethylene) insulated cables are used. The

improvement of the XLPE insulation material combined with the modern design of

the cable enable to manufacture cables even for the extra high voltage level.

All kind of low, medium and high voltage cables are delivered and stored on

cable drums. The maximum available cable length is mainly specified by the

diameter (1-core ore 3-core cable) and the voltage level of the cable.In low voltage networks, the connection of the fault location equipment in

most cases is applied to the faulty core that is expected to flash over to the ground

core. On the other hand, the mains supply is tapped between one healthy core and

ground. This may force the operating earth (OE) to rise up to a higher potential an

usual. According to this potential lift, the potential of the safety earth (SE) will also

increase. Due to this potential lift, a larger potential difference and so a higher

voltage between neutral wire (connected to OE) and phase will occur, which may

cause a harmful effect to the equipment’s mains input.


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CHAPTER 2

LITERATURE SURVEY

Seung(2004) in his paper “a new fault location algorithm by direct analysis

of 3 phase circuit in distribution systems” discusses the unbalanced nature of

distribution systems due to single-phase laterals and loads gives difficulty in the

fault location. This paper proposes a new fault location algorithm developed by the

direct analysis of 3-phase circuit for unbalanced distribution systems, which has

not been investigated due to high complexity. The proposed algorithm overcomes

the limit of the conventional algorithm, which requires the balanced system. It is

applicable to any power system, but especially useful for the unbalanced

distribution systems. Its effectiveness has been proved through many EMTP

simulations.

Dr. Aditya Goel & Ravi Shankar Mishra(2009) in his paper “remote data

acquisition using wireless – scada system” proposes that Supervisory Control and

Data Acquisition (SCADA) is a process control system that enables a site operator

to monitor and control processes that are distributed among various remote sites. A

properly designed SCADA system saves time and money by eliminating the need

for service personnel to visit each site for inspection, data collection/logging or

make adjustments. Supervisory Control and Data Acquisition systems are

computers, controllers, instruments; actuators, networks, and interfaces that

manage the control of automated industrial processes and allow analysis of those

systems through data collection.

A.Ngaopitakkul (2010) in his paper “identification of fault locations in

under-ground distribution system using discrete wavelet transform”

proposes a technique for detecting faults in underground system is presented.


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Discrete Wavelet Transform (DWT) based on traveling wave is employed in

order to detect the high frequency components and to identify fault locations in the

underground distribution system. The first peak time obtained from the faulty bus

is employed for calculating the distance of fault from sending end. The validity of

the proposed technique is tested with various fault inception angles, fault locations

and faulty phases. The result is found that the proposed technique provides

satisfactory result and will be very useful in the development of power systems

protection scheme.

Lorenzo Peretto (2011) in his paper addresses the topic of “ Fault location in

power networks with cable lines ”that in the era of smart grid the demand of

intelligent measurement systems capable of providing quickly and with high

accuracy the right location of faults in power networks is growing fast. Many

proposals can be found in literature relevant to different approaches. Some

commercial instrumentation is also available on the market for this purpose.

Protection relays implementing this feature can either be found. This paper

presents the experimental results of a measurement campaign carried out in the

MV power network in the city of Milan (Italy).

Xia Yang (2012) in his paper “Fault Location for Underground Power Cable

Using Distributed Parameter Approach” proposes an extensive fault location model

for underground power cable in distribution system using voltage and current

measurements at the sending-end. This analysis is used to calculate a fault distance

in single section using voltage and current equations. The extension to multi-

section is further analyzed based on Korean distribution systems.


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CHAPTER 3

BLOCK DIAGRAM

3.1 GENERAL

The project deals with the identification and location of faults in

underground power cables. The circuit implementation is done using distributed

parameter approach by assuming the overall network as two zones viz, zone1 and

zone2. These zones are synchronized with the server monitoring unit to acquire the

data by using Zigbee transceiver. These are explained in the block diagram given

below in fig.3.1

3.2. OVER ALL BLOCK DIAGRAM

Fig 3.1Over all block diagram

The detailed block diagram of the zones are given in fig.3.2, 3.3

AC

SUPPLY

ZONE 1

ZONE 2

REMOTE

MONITORING

UNIT(WSCADA)


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Fig 3.2 Zone-1(Open/Close circuit detection node)

Fig 3.3 Zone-2(Over current/Low voltage detection node)

PIC

ControllerWireless

Transceivers

Voltage

Sensor

Liquid Crystal Display

Current

Sensor

AC

SUPPLY

Open/

Short

Circuit Load

PIC

ControllerWireless

Transceivers

Voltage

Sensor

Liquid Crystal Display

Current

Sensor

AC

SUPPLY

Load

POT

Load


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Fig 3.4 Server monitoring unit

3.3.1 ZONE-1(OPEN/CLOSE CIRCUIT DETECTION NODE)

In zone1 for our conveniences we manually trigger the short circuit and open

circuit faults. The voltage and current sensor continuously monitors the line and

the data are sent to the server monitoring unit. Using the data further control

measures can be taken. The uncertainty of the location of fault is between 2 to 3

meter in real-time.

3.3.2 ZONE-2(OVER CURRENT/LOW VOLTAGE DETECTION NODE)

The zone2 comprises of a potential transformer and an additional load to

trigger the over current and over voltage faults. Similar to the zone1 this also

comprises of PIC microcontroller which helps the sensor to communicate with the

wireless transceiver.

Wireless

Transceiver

PIC

Controller

Server

System

(WSCADA)

TTL to

RS232


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3.3.3 SERVER MONITORING UNIT

The server monitoring unit consists of a wireless transceiver which receives

the data from the zones and displays on the personal computer. The interface

between the Zigbee and PC is done by the PIC microcontroller and transistor-

transistor logic cable RS232.

3.3.4 CABLE FAULTS

A cable fault can be defined as any defect, inconsistency, weakness or non-

homogeneity that affects the performance of a cable. All faults in underground

cables are different and the success of a cable fault location depends to a great

extent on practical aspects and the experience of the operator. To accomplish this,

it is necessary to have personnel trained to test the cables successfully and to

reduce their malfunctions. The further explanation about Cable faults is shown in

chapter 4.

3.3.5 ZIGBEE

ZigBee is the name of a specification for a suite of high level communication

protocols using small, low-power digital radios based on the IEEE 802.15.4-2006

standard for wireless personal area networks (WPANs), such as wireless

headphones connecting with cell phones via short-range radio. The technology is

intended to be simpler and cheaper than other WPANs, such as Bluetooth. ZigBee

is targeted at radio-frequency (RF) applications that require a low data rate, long

battery life, and secure networking. The further explanation about Zigbee is shownin chapter 6.


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3.3.6 WSCADA

Wireless SCADA system for monitoring & accessing the performance of

remotely situated device parameter such as temperature, pressure, humidity on real

time basis. For this we have used the infrastructure of the existing mobile network,

which is based on GPRS technique Supervisory Control and Data Acquisition

(SCADA) is a field of constant development and research. This project investigates

on creating an extremely low cost device. The further explanation about WSCADA

is shown in chapter 5.

3.3.7 SENSOR

3.3.7.1 VOLTAGE SENSOR:

A transformer converts one voltage to another. It only works with alternating

current, in which the direction of the electrical flow periodically changes. Since

energy cannot be created or destroyed, the power passed by a transformer remains

the same at the output. Since the voltage changes, the current must change so that

the amount of power is the same. The further explanation about voltage sensor is

shown in chapter 8.1.

3.3.7.2 CURRENT SENSOR:

A single wire carrying current generates a magnetic field. You can visualize

this by making a loose fist with your right hand, and sticking your thumb out. The

thumb indicates the direction the current is flowing in the single wire, and your

fingers represent the magnetic lines of flux circling around the wire (current). This

is called the right-hand-rule. The further explanation about current sensor is shown

in chapter 8.2.


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3.3.8 PIC MICRO CONTROLLER

PICs are popular with developers and hobbyists alike due to their low cost,

wide availability, large user base, extensive collection of application notes,

availability of low cost or free development tools, and serial programming (and re-

programming with flash memory) capability. The controller chosen for my

application is PIC16F877A. It’s a8-bit controller. The further explanation about

PIC microcontroller is shown in chapter 7.

3.3.9 LIQUID CRYSTAL DISPLAY:

Frequently, a microcontroller program must interact with the outside world

using input and output devices that communicate directly with a human being. One

of the most common devices attached to microcontroller port is an LCD display.

Some of the most common LCDs connected to the microcontroller are 16x2 and

20x2 displays. Fortunately, a very popular standard exists which allows us to

communicate with the vast majority of LCDs regardless of their manufacturer. The

further explanation about Liquid crystal display is shown in chapter 9.4.

3.3.10 MP LAB IDE

For programming the PIC Microcontroller we use embedded C-

programming. The Microcontroller is programmed for serial communication by

enabling In-Circuit Debugger and also the coding is written so as to collect the

digital data from the Analog to digital convertor. A hi-tech cross compiler is a

software, which compiles a source code of one environment as an object file to be

executed in different environment. It is broadly classified into development and

simulation. The simulation is handled by D Scope. Even the corresponding power

value can also be displayed in a text box.


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CHAPTER 4

FAULT

4.1 INTRODUTION

A cable fault can be defined as any defect, inconsistency, weakness or non-

homogeneity that affects the performance of a cable. All faults in underground

cables are different and the success of a cable fault location depends to a great

extent on practical aspects and the experience of the operator. To accomplish this,

it is necessary to have personnel trained to test the cables successfully and to

reduce their malfunctions.

4.2 CABLE FAULT TYPES

There are many type of cable fault occurring here we discuss some the

commonly occurring faults,

4.2.1 Fault between core-core and / or core - sheath:

Low resistive faults (R < 100 - 200 Ω)

o short circuit

High resistive faults (R > 100 - 200 Ω)

o Intermittent faults (breakdown or flash faults)

o Interruption (cable cuts)

4.2.2 Defects on the outer protective shield (PVC, PE):

Cable sheath faults

Most of the cable faults occur between cable core and sheath. Furthermore,

very frequently blown up open joint connections or vaporized cable sections can

cause the core to be interrupted. To figure out whether such a fault is present, the

loop resistance test shall be done. By using a simple multimeter, the continuity in

general can be measured.


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The easiest way to perform this test is to keep the circuit breaker at the far

end grounded. Corrosion of the cable sheath may increase the line resistance. This

is already an indication for possible part reflections in the TDR result.

4.3 CABLE FAULT LOCATION PROCEDURE

Cable fault location as such has to be considered as a procedure

Covering the following steps and not being only one single step.

Fault Indication

Disconnecting and Earthing

Fault Analyses and Insulation Test

Cable Fault Prelocation

Cable Route Tracing

Precise Cable Fault Location (Pinpointing)

Cable Identification

Fault Marking and Repair

Cable Testing and Diagnosis

Switch on Power

4.4 CABLE FAULT PRELOCATION

The cable fault is pre located by analyzing the length of the cable by using

the following methods

4.4.1 Impulse Reflection Method TDR

The TDR method is the most established and widely used measuring method

for determination of

· the total length of a cable

· the location of low resistive cable faults

· the location of cable interruptions

· the location of joints along the cable


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The Time Domain Reflectometer IRG (BAUR abbreviation for Impulse

Reflection Generator) sends a low voltage impulse into the cable under test. The

low voltage impulse (max. 160V) travels through the cable and is reflected

positively at the cable end or at any cable interruption (cable cut). At a short circuit

point this low voltage impulse is reflected negatively. The Time Domain

Reflectometer IRG is measuring the time between release and return of the low

voltage impulse.

4.4.2 Multiple Impulse Method (SIM/MIM)

The Multiple Impulse Method is the most advanced cable fault prelocation

method available. Every cable fault that is either a high resistive or intermittent

fault cannot be indicated by means of the TDR method. The low voltage impulse

sent out by the Time Domain Reflectometer is not reflected at the faulty position,

as the fault impedance compared to the insulation impedance of the healthy part of

the cable is not significantly lower.

4.4.3 Bridge Method

All faults having the characteristic to happen between two defined cores and

therefore two parallel wire scan be prelocated with any of the previously

mentioned cable fault prelocation methods based on pulse reflectometry. Certain

cable structures enable cable faults to happen from a core to the outside and

therefore the soil.

Bridge methods are basically used for prelocation of low resistive faults. By

using a high voltage source that is integrated in the latest generation of measuring

bridge instruments even high resistive fault scan be prelocated.

All bridge measurement methods that work with direct current for locating

faults in cables (Glaser and Murray) are based in principle on modified Wheatstone

circuits.


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CHAPTER 5

WSCADA

5.1 INTRODUCTION

Wireless SCADA system for monitoring &accessing the performance of

remotely situated device parameter such as temperature, pressure, humidity on real

time basis. For this we have used the infrastructure of the existing mobile network,

which is based on GPRS technique Supervisory Control and Data Acquisition

(SCADA).

5.1.1 NEED FOR SCADA

This project investigates on creating an extremely low cost device which can

be adapted to many different SCADA applications via some very basic

programming, and plugging in the relevant peripherals. Much of the price in some

expensive SCADA applications is a result of using specialized communication

infrastructure. The application of infrastructure, in the proposed scheme the cost

will come down. Additionally the generic nature of the device will be assured.

Wireless SCADA deals with the creation of an inexpensive, yet adaptable

and easy to use SCADA device and infrastructure using the mobile telephone

network, in particular, the General Packet Radio Service (GPRS).

The hardware components making up the device are relatively

unsophisticated, yet the custom written software makes it re-programmable over

the air, and able to provide a given SCADA application with the ability to send and

receive control and data signals at any non-predetermined time.

5.2 FEATURES OF WSCADA

GPRS is a packet- based radio service that enables “always on” connections,

eliminating repetitive and time-consuming dial-up connections.


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It will also provide real throughput in excess of 40 Kbps, about the same

speed as an excellent landline analog modem connection. From the wireless

SCADA system which is proposed in setup the temperature of around 30◦C could

be sufficiently recorded from remote location. In the similar manner reading of

electric energy meter could be read 223 Kilo Watt Hour (KWH) or 223 Unit.

The properly designed SCADA system saves time and money by eliminating

the need of service personal to visit each site for inspection, data collection

/logging or make adjustments. Supervisory Control and Data Acquisition

(SCADA) is a process control system that enables a site operator to monitor and

control processes that are distributed among various remote sites.

Supervisory Control and Data Acquisition systems are computers,

controllers, instruments, actuators, networks, and interfaces that manage the

control of automated industrial processes and allow analysis of those systems

through data collection .

They are used in all types of industries, from electrical distribution systems,

to food processing, to facility security alarms. Supervisory control and data

acquisition is used to describe a system where both data acquisition and

supervisory control are performed. Mobile Supervisory Control and Data

Acquisition (referred to as Mobile SCADA) is the use of SCADA with the mobile

phone network being used as the underlying communication medium.

GSM is a wireless communication technology; most popular today for

transmitting data anywhere in the world through SMS with the help of mobile

phones.

General Packet Radio Service (GPRS) is chosen as the specific mobile

communication protocol to use as it provides an always on-line Inter connection

without any time based charges.


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Display and

controlAuxiliary

Prog.

I/OC.P.U.

Communication

interface

RTU RTU RTU

SMS is a globally accepted wireless service that enables the transmission of

alphanumeric messages between mobile subscribers and external systems such as

electronic mail, paging, and voice-mail systems. It is a store and forward way of

transmitting messages to and from mobiles. SMS benefits includes the delivery of

notifications and alerts, guaranteed message delivery, reliable and low cost

communication mechanism for concise information, ability to screen messages and

return calls in a selective way and increased subscriber productivity.

5.3 COMPONENTS OF THE SCADA SYSTEM

SCADA systems typically are made of four components:


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5.3.1Master Unit

This is heart of the system and is centrally located under the operator's

control

5.3.2Remote Unit

This unit is installed from where the process is actually monitored. It gathers

required data about the process and sends it to the master unit.

5.3.3Communication Mode

This unit transmits signals/data between the master unit and the remote unit.Communication mode can be a cable, wireless media, satellite etc.

Computer receives data from RTUs via the communication interface.

Operators control base one or more CRT terminals for display. With this, terminal

it is possible to execute supervisory control commands and request the display of

data in alpha numerical formats arranged by geographical location and of type.


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CHAPTER 6

ZIGBEE

6.1 INTRODUCTION

ZigBee is the name of a specification for a suite of high level communication

protocols using small, low-power digital radios based on the IEEE 802.15.4-2006

standard for wireless personal area networks (WPANs), such as wireless

headphones connecting with cell phones via short-range radio.

6.1.1 NEED FOR TECHNOLOGY

The technology is intended to be simpler and cheaper than other WPANs,such as Bluetooth. ZigBee is targeted at radio-frequency (RF) applications that

require a low data rate, long battery life, and secure networking. The Zigbee

concept is divided into four sections. The sections are as follows:

Wireless Sensor Networking

WSN Technology

IEEE 802.15.4 Standard

ZigBee Standard

6.2 WSN CONCEPT

Wireless sensor network is a network of small spatially distributed devices

that can communicate with each other over the air. Wireless sensor networks is a

less expensive, more flexible and highly reliable alternative for existing wired

monitoring and controlling solutions. WSN systems are rapidly replacing wires in

weather stations, light switches, HVAC systems, and many other areas.


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6.2.1 The main purposes of WSN deployment are

6.2.1.1 To Monitor

Data from remote sensors of different types (temperature, pressure, motion,

vibrations, etc.) with WSN connectivity can be easily collected by central unit for

further processing and analysis

6.2.1.2 To Control

Actuators (switches, valves, sound emitters, robots, etc.) can be controlled

remotely by commands sent over the air

6.2.1.3 Both to monitor and to control Measurements collected from sensors can be immediately used to control

actuators present in the same wireless network

Fig. 6.1 WSN example for remote sensors monitoring

Low power mesh networking. IEEE 802.15.4 Standard, based on Motorola’s

proposal. “Low power”, “Networked”, “Open standard” Personal Operating Space

(POS) of 10m radius, or greater range Mesh self-healing network.


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6.3 COMPARISON OF ZIGBEE AND BLUETOOTH:

Characteristic Zigbee Bluetooth

Range

As designed

Special kit or outdoors

Data rate

Security

Operating frequency

Complexity

Network topology

Number of devices pernetwork

10-100 metres

Up to 400 metres

20-250 Kbps

128 bit AES and application

layer user definable

868 Mhz,902-928 Mhz,2.4

Ghz ISM

Simple

Adhoc, star, mesh hybrid

2 to 65,000

10 metres

100+ meters dep.on radio

1 Mbps

64 bit,128 bit

2.4 Ghz

Complex

Adhoc piconets

8

TABLE 6.1


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CHAPTER 7

PIC CONTROLLER

7.1 INTRODUCTION

The microcontroller that has been used for this project is from PIC series.

PIC microcontroller is the first RISC based microcontroller fabricated in CMOS

(complementary metal oxide semiconductor) that uses separate bus for instruction

and data allowing simultaneous access of program and data memory.

The main advantage of CMOS and RISC combination is low power

consumption resulting in a very small chip size with a small pin count. The main

advantage of CMOS is that it has immunity to noise than other fabrication

techniques.

7.1.1 PIC (16F877)

Various microcontrollers offer different kinds of memories. EEPROM,

EPROM, FLASH etc. are some of the memories of which FLASH is the most

recently developed. Technology that is used in pic16F877 is flash technology, so

that data is retained even when the power is switched off. Easy Programming and

Erasing are other features of PIC 16F877.

7.2 FEATURES

7.2.1 High-Performance RISC CPU

Only 35 single-word instructions to learn. All single-cycle instructions

except for program branches, which are two-cycle. Operating speed: DC – 20 MHz

clock input DC – 200 ns instruction cycle Up to 8K x 14 words of Flash Program

Memory, Up to 368 x 8 bytes of Data Memory (RAM), Up to 256 x 8 bytes of


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EEPROM Data Memory. Pin out compatible to other 28-pin or 40/44-pin

PIC16CXXX and PIC16FXXX microcontrollers.

7.2.2 Peripheral Features

Timer0: 8-bit timer/counter with 8-bit pre-scaler. Timer1: 16-bit

timer/counter with pre-scaler, can be incremented during Sleep via external

Crystal/clock.Timer2: 8-bit timer/counter with 8-bit period register, pre-scaler and

post-scaler. Two Capture, Compare, PWM modules Capture is 16-bit, max

resolution is 12.5 ns Compare is 16-bit, max resolution is 200 ns PWM max

resolution is 10- bit Synchronous Serial Port (SSP) with SPI™ (Master mode) and

I2C™ (Master/Slave) Universal Synchronous Asynchronous Receiver Transmitter

(USART/SCI) with 9-bit address detection. Parallel Slave Port (PSP) – 8 bits wide

with external RD, WR and CS controls (40/44pin only). Brown-out detection

circuitry for Brown-out Reset (BOR).

7.2.3 Analog Features

10-bit, up to 8-channel Analog-to-Digital converter (A/D). Brown-out Reset(BOR). Analog Comparator module with two analog comparators. Programmable

on-chip voltage reference (VREF) module. Programmable input multiplexing from

device inputs and internal voltage reference. Comparator outputs are externally

accessible.

7.2.4 Special Microcontroller Features

100,000 erase/write cycle Enhanced Flash program memory typical.

1,000,000 erase/write cycle Data EEPROM memory typical. Data EEPROM

Retention > 40 years. Self-reprogrammable under software control. In-Circuit

Serial Programming™ (ICSP™) via two pins.


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Single-supply 5V In-Circuit Serial Programming. Watchdog Timer (WDT)

with its own on-chip RC oscillator for reliable operation. Programmable code

protection. Power saving Sleep mode. Selectable oscillator options. In-Circuit

Debug (ICD) via two pins

7.3 CMOS TECHNOLOGY

Low-power, high-speed. Flash/EEPROM technology. Fully static design.

Wide operating voltage range (2.0V to 5.5V). Commercial and Industrial

temperature ranges. Low-power consumption

7.4 DEVICE OVERVIEW

This document contains device specific information about the following

devices. The pin diagram of pic controller 16F877A is shown in fig 7.1

• PIC16F873A

• PIC16F874A

• PIC16F876A

• PIC16F877A

PIC16F873A/876A devices are available only in 28-pin packages, while

PIC16F874A/877A devices are available in 40-pin and 44-pin packages.

All devices in thePIC16F87XA family share common architecture with the

following differences:

The PIC16F873A and PIC16F874A have one-half of the total on-chip

memory of the PIC16F876A and PIC16F877A. The 28-pin devices have three I/O

ports, while the 40/44-pin devices have five. The 28-pin devices have fourteen


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interrupts, while the 40/44-pin devices have fifteen. The 28-pin devices have five

A/D input channels, while the 40/44-pin devices have eight. The Parallel Slave

Port is implemented only on the 40/44-pin devices.

TABLE 7.1


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7.5PIN DIAGRAM

FIGURE 7.1


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7.6 I/O PORTS

Some pins for these I/O ports are multiplexed with an alternate function for

the peripheral features on the device. In general, when a peripheral is enabled, that

pin may not be used as a general purpose I/O pin.

Additional Information on I/O ports may be found in the IC micro™ Mid-

Range Reference Manual,

7.6.1 PORTA AND THE TRIS A REGISTER

PORTA is a 6-bit wide bi-directional port. The corresponding data direction

register is TRISA. Setting a TRISA bit (=1) will make the corresponding PORTA

pin an input, i.e., put the corresponding output driver in a Hi-impedance mode.

Clearing a TRISA bit (=0) will make the corresponding PORTA pin an output, i.e.,

put the contents of the output latch on the selected pin.

7.6.2 PORTB AND TRISB REGISTER

PORTB is an 8-bit wide bi-directional port. The corresponding datadirection register is TRISB. Setting a TRISB bit (=1) will make the corresponding

PORTB pin an input, i.e., put the corresponding output driver in a hi-impedance

mode. Clearing a TRISB bit (=0) will make the corresponding PORTB pin an

output, i.e., put the contents of the output latch on the selected pin. Three pins of

PORTB are multiplexed with the Low Voltage Programming function; RB3/PGM,

RB6/PGC and RB7/PGD. The alternate functions of these pins are described in the

Special Features Section. Each of the PORTB pins has a weak internal pull-up. A

single control bit can turn on all the pull-ups.


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This is performed by clearing bit RBPU (OPTION_REG). The weak

pull-up is automatically turned off when the port pin is configured as an output.

The pull-ups are disabled on a Power-on Reset.

7.6.3 PORTC AND THE TRIS C REGISTER

PORTC is an 8-bit wide bi-directional port. The corresponding data

direction register is TRISC. Setting a TRISC bit (=1) will make the corresponding

PORTC pin an input, i.e., put the corresponding output driver in a hi-impedance

mode. Clearing a TRISC bit (=0) will make the corresponding PORTC pin an

output, i.e., put the contents of the output latch on the selected pin. PORTC is

multiplexed with several peripheral functions. PORTC pins have Schmitt Trigger

input buffers.

7.6.4 PORTD AND TRISD REGISTERS

This section is not applicable to the 28-pin devices. PORTD is an 8-bit port

with Schmitt Trigger input buffers. Each pin is individually configurable as an

input or output. PORTD can be configured as an 8-bit wide microprocessor Port

(parallel slave port) by setting control bit PSPMODE (TRISE). In this mode,

the input buffers are TTL.

7.6.5 PORTE AND TRISE REGISTER

PORTE has three pins RE0/RD/AN5, RE1/WR/AN6 and RE2/CS/AN7,

which are individually configurable as inputs or outputs. These pins have Schmitt

Trigger input buffers.

The PORTE pins become control inputs for the microprocessor port when

bit PSPMODE (TRISE) is set. In this mode, the user must make sure that the


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TRISE bits are set (pins are configured as digital inputs). Ensure ADCON1 is

configured for digital I/O. In this mode the input buffers are TTL.

PORTE pins are multiplexed with analog inputs. When selected as an analog

input, these pins will read as '0's. TRISE controls the direction of the RE pins, even

when they are being used as analog inputs. The user must make sure to keep the

pins configured as inputs when using them as analog inputs.

7.7 STATUS REGISTER

FIGURE 7.2


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TABLE 7.2

7.8 MEMORY ORGANIZATION

There are three memory blocks in each of the PIC16F87XA devices. The

program memory and data memory have separate buses so that concurrent access

can occur and is detailed in this section

7.8.1 Program Memory Organization

The PIC16F87XA devices have a 13-bit program counter capable of

addressing an 8K word x 14 bit program memory space. The PIC16F876A/877A

devices have 8K words x 14 bits of Flash program memory, whilePIC16F873A/874A devices have 4K words x 14 bits. Accessing a location above

the physically implemented address will cause a wraparound. The Reset vector is

at 0000h and the interrupt vector is at 0004h.


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7.9 REGISTER FILE MAP:

FIGURE 7.3

7.9.1 GENERAL PURPOSE REGISTER FILE

The register file can be accessed either directly or indirectly through the File

Selected Register (FSR). There are some Special Function Registers used by the

CPU and peripheral modules for controlling the desired operation of the device.

These registers are implemented as static RAM. The Special Function Registers

can be classified into two sets; core (CPU) and peripheral. Those registers

associated with the core functions.


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CHAPTER 8

SENSOR

8.1 INTRODUCTION

The sensor are used to continuously sense the parameter needed to be

measured in this project voltage and current sensor. The input to this sensors are

given from power supply through a step down transformer. The output is given to

the microcontroller.

8.2 VOLTAGE SENSOR

Figure8.1

A transformer converts one voltage to another. It only works with

alternating current, in which the direction of the electrical flow periodically

changes.

R1D1

filter

R2

rectifier

230v AC 50Hz C1

filter capacitor

D3

D2 to ADC0

T1

voltage Sensor

1 5

4 8 D4


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Since energy cannot be created or destroyed, the power passed by a

transformer remains the same at the output. Since the voltage changes, the

current must change so that the amount of power is the same.

The high-current low-voltage windings have fewer turns of thicker wire.

The thicker wire helps carry more current. The high-voltage, low current

windings have more turns of thinner wire. The thinner wire carries less current,

but at a higher voltage.

Some transformers have equal numbers of windings on both coils. These

"isolation" transformers are used to prevent direct current flow between electriccircuits, while transferring power. Small transformers are often used to isolate

and link different parts of radios.

The fig.8.1 represents the voltage sensor. The input ac supply is given to

the step-down transformer which converts the 230v into 12v. During positive

half cycle the points 5 and 8 are positive and negative respectively. At this

instance diode D1 and D4 conduct. During negative half cycle the polarity of

points 5 and 8 gets reversed. Now the diode D2 and D3 conducts. The output of

the full wave rectifier is given to the ADC unit of the microcontroller which

converts the analog data into digital data. Since PIC 16F877A is 8bit controller

its capable of delivering 8 level of output. So that we are able to get greater

accuracy.


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8.3 CURRENT SENSOR

Figure8.2

The figure 8.2 represents a current transformer. The current transformer

operates only when loads is acting series to the supply.During positive half

cycle the points 5 and 8 are positive and negative respectively. At this instance

diode D1 and D4 conduct. During negative half cycle the polarity of points 5

and 8 gets reversed. Now the diode D2 and D3 conducts. The output of the full

wave rectifier is given to the ADC unit of the microcontroller which converts

the analog data into digital data. Since PIC 16F877A is 8bit controller its

capable of delivering 8 level of output. So that we are able to get greater

accuracy.

Current transformers are used so that ammeters and the current coils of

other instruments and relays need not be connected directly to high voltage

lines. In other words, these instruments and relays are insulated from high

voltages.

R1

filter

R2

rectifier

LOAD

230v AC

50Hz C1

f ilter capacitor D2 to ADC1

T11 5

4 8

current Sensor

D1 D3

D4


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CT's also step down the current in a known ratio. The use of CT means

that relatively small and accurate instruments, relays and control devices of

standardized design can be used in circuits.

The CT has separate primary and secondary windings. The primary

winding which consists of few turns of heavy wire, wound on a laminated iron

core is connected in series with one of the line wires. The secondary winding

consists of a greater number of turns of a smaller size of wire. The primary and

secondary windings are wound on the same core.

The current rating of the primary winding of a CT is 100A. The primary

winding has three turns and the secondary winding has 60 turns. The secondary

winding has the standard current rating of 5A; therefore the ratio between the

primary and secondary current is 100/5 or 20/1.The primary current is 20 times

greater than the secondary current. Since the secondary winding has 60 turns

and the primary winding has 3 turns, the secondary winding has 20 times as

many turns as the primary winding. For a CT, then the ratio of primary to

secondary currents is inversely proportional to the ratio of primary to secondary

turns.

The CT in the figure has polarity markings in that the two high voltage

primary leads are marked 1 and 4, and the secondary leads are marked 5 and

8.When 1 is instantaneously positive, 5 is positive at the same moment. Some

CT manufacturers mark only the 1 and 5 leads. When connecting the CT's in

circuits; the 1 lead is connected to the line lead feeding from the source while

the 4 lead is connected directly to the ammeter. Note that one of the secondary

leads is grounded as a safety precaution to eliminate high voltage hazards.


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CHAPTER 9

HARDWARE IMPLEMENTATION

9.1 GENERAL

The hardware circuit implementation deals with the wiring of sensor with the

load and with pic microcontroller unit. The pic controller is connected with

wireless transceiver which transmits and receives data. In the server monitoring

unit transceiver is interfaced with the PC using RS232 cable.

9.2 HARDWARE DESCRIPTION

The hardware implementation includes the following circuits

1. POWER SUPPLY CIRCUIT

2. SENSORS

3. PIC CONTROLLER

4. ZIGBEE MODEM

5. PERSONAL COMPUTER

6.

LCD7. RS 232

9.2.1 CIRCUIT DESCRIPTION

The overall circuit consists of power supply unit which allows the flow of

power through our circuit. In this unit the rectification, filtering and other quality

enhancement work are done the output of this unit is given to the zones which

means the load centers. These zones are connected with fault detection unit which

senses the fault and process the output through the microcontroller. The output of

microcontroller is given to Zigbee transceiver which transmits the data.


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9.3 OVERALL CIRCUIT

Fig 9.1Over all circuit

MICROCONTROLLER

VCC

VCC

C7

1 MFD

C3

470MFD 25V

rx

U1

LM7805C/TO220

1 3

2

IN OUT

G N D

C8

CAPACITOR

Power Supply Unit

PIC16F877A

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

29

30

31

32

33

34

35

36

37

38

39

40MCLR

AN0

AN1

AN2

AN3

AN4

AN5

RE0

RE1

RE2

Vdd

Vss

osc1

osc2

RC0

RC1

RC2

RC3

RD0

RD1 RD2

RD3

RC4

RC5

RC6

RC7

RD4

RD5

RD6

RD7

Vss

Vdd

RB0

RB1

RB2

RB3

RB4

RB5

RB6

RB7

through RS232 TXD

sending to the PC

J1

+12V 1A

1 2

4MHz

CRYSTAL OSCILLATOR

C7

1 MFD

reset switch

VCC

D1

1N4007

1 2

RESET SWITCH

tx

C7

1 MFD

D2

LED

TXD

for system Interfacing

for ZigbeeInterfacing

U4

MAX232

13

8

11

10

1

3

4

5

2

6

12

9

14

7

16

14

R1IN

R2IN

T1IN

T2IN

C+

C1-

C2+

C2-

V+

V-

R1OUT

R2OUT

T1OUT

T2OUT

VCC

GND

through RS232 RXD

C1

0.1MFD

RXD

C7

1 MFD receiving from the zigb

tx

RXD

VCC

R1

RESISTOR

P1

SERIAL CON

5

9

4

8

3

7

2

6

1

C2

0.1MFD

VCC

R11k

TXD

C2


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9.3.1 CIRCUIT OPERATION

The input ac power supply is given to the zones. In the zones the 230v is

stepped down to 12v using a step-down transformer. The 12v output is given to the

voltage and current sensors which senses the line voltage and current. The analog

output of the sensors is given to the ADC unit of pic controller. The digital output

is compared with the threshold value. During stable operation of the system the

voltage and current values are within the tolerance limit. Hence the output of the

controller calls the LCD to display as stable system. During faulted condition the

sensors senses the voltage and current value and its output is given to controller

which compares the value with threshold value. According to the output of thesensors the type of fault occurred is displayed in the LCD by the call of interrupt in

the controller. The location of the fault can be determined by using the mac id

assigned to the Zigbee at each zone. From the Zigbee transceiver the data is send to

the remote monitoring unit.

9.3.2 RS232 INTERFACING

Fig 9.2

C5

0.1MFD

RXD0_RS232

+3.3V

TXD0_RS232

RXD1_RS232

RXD0

P1

UART1

594837261

TXD1_RS232

RTS

TXD0

C60.1MFD

TXD1

C7

0.1MFD

RXD0_RS232

TXD0_RS232

DTR

C80.1MFD

RXD1

U3

MAX3232_SOIC

1516

138

1011

1345

26

129

147

G N D

V C C

R 1IN

R 2 IN

T2 IN

T 1 I N

C 1+

C 1-

C 2 +

C 2 -

V +

V -

R 1O U T

R 2 O U T

T1O U T

T2 O U T

+3.3V

RXD1_RS232

P2

UART0_ISP

594837

261

TXD1_RS232

C9

0.1MFD


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9.4 POWER SUPPLY

The power supply is very important section of all electronic devices as all the

electronic devices works only in DC. One important aspect of the project is that the

power supply should be compact. Most electronic devices need a source of DC

power.

Power supply unit consists of following units:

Step down transformer

Rectifier unit

Input filter

Regulator unit

Output filter

The circuit is powered by a 12V dc adapter, which is given to

LM7805voltage regulator by means of a forward voltage protection diode and is

decoupled by means of a 0.1 μf capacitor. The voltage regulator gives an output of

exactly 5V dc supply. The 5V dc supply is given to all the components including

the Microcontroller, the serial port, and the IR transmitters and sensors.

The AC supply which when fed to the step down transformer is leveled down

to 12 volts AC . This is then fed to full wave rectifier which converts it in to 12

volts DC. This is then passed to a filter to remove the ripples. Then it is fed to a

voltage regulator that converts 12 V to 5 V stable voltages and currents.


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Fig 9.3

9.4.1 STEPDOWN TRANSFORMER

The step down transformer is used to step down the main supply voltage

from 230AC to lower value. This 230AC voltage cannot be used directly, thus its

stepped down. The transformer consists of primary and secondary coils. To reduce

or step down the voltage, the transformer is designed to contain less number ofturns in its secondary core. Thus the conversion from AC to DC is essential. This

conversion is achieved by using the rectifier circuit.

9.4.2 RECTIFIER UNIT

The Rectifier circuit is used to convert AC voltage into its corresponding DC

voltage. There are Half-Wave and Full-Wave rectifiers available for this specific

function. The most important and simple device used in rectifier circuit is the

diode. The simple function of the diode is to conduct when forward biased and not

to conduct when reverse biased.

U1LM7805C/TO220

1 3

2

IN OUT

G N D

+5VDC U2 AMS1117-3.3/ SOT223

3 2

1

VIN VOUT

G N D

C4

0 . 1

M F DC1

0 . 1

M F D

+3.3V+5VDC

J1

CONN JACK

123

C3

4 7 0 M F D

L1

LED

C6

1 0 M F DC2

0 . 1

M F D

C5

0 . 1

M F

D

R14.7K


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The forward bias is achieved by connecting the diode’s positive with of positive of

battery and negative with battery’s negative. The efficient circuit used is full wave

bridge rectifier circuit. The output voltage of the rectifier is in rippled form, the

ripples from the obtained DC voltage are removed using other circuits available.

The circuit used for removing the ripples is called Filter circuit.

9.4.3 INPUT FILTER

Capacitors are used as filters. The ripples from the DC voltage are removed

and pure DC voltage is obtained. The primary action performed by capacitor is

charging and discharging. It charges in positive half cycle of the AC voltage and it

will discharge in its negative half cycle, so it allows only AC voltage and does not

allow the DC voltage. This filter is fixed before the regulator. Thus the output is

free from ripples.

9.4.4 REGULATOR UNIT

Regulator regulates the output voltage to be always constant. The output

voltage is maintained irrespective of the fluctuations in the input AC voltage. As

Band then the AC voltage changes, the DC voltage also changes. This to avoid

these regulators are used. Also when the internal resistance of the power supply is

greater than 30 ohms, the pullup gets affected. Thus this can be successfully

reduced here. The regulators are mainly classified for low voltage and for high

voltage.

9.4.4.1 IC VOLTAGE REGULATORS

Voltage regulators comprise a class of widely used ICs. Regulator IC units

contain the circuitry for reference source, comparator amplifier, control device and

overload protection all in a single IC.


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A Power Supply can be built using a transformer connected to the AC supply

line to step the ac voltage to desired amplitude, then rectifying that ac voltage

using IC regulator. The regulators can be selected for operation with load currents

from hundreds of milli amperes to tens of amperes, corresponding to power ratings

from milli watts to tens of watts. The Micro controller and PC work at a constant

supply voltage of +5V,-5Vand +12V and -12V respectively. The regulators are

mainly classified for positive and negative voltage.

9.4.4.2 LM 7805 VOLTAGE REGULATOR

9.4.4.2.1 Features

• Output Current up to 1A

• Output Voltages of 5, 6, 8, 9, 10, 11, 12, 15, 18, 24V

• Thermal Overload Protection

• Short Circuit Protection

• Output Transistor Safe Operating area Protection

9.4.5 OUTPUT FILTER

The filter circuit is often fixed after the regulator circuit. Capacitor is most

often used as filter. The principle of the capacitor is to charge and discharge. It

charges during the positive half cycle of the AC voltage and discharges during the

negative half cycle. So it allows AC voltage and not DC voltage. This filter is fixed

after the regulator circuit to filter any of the possibly found ripples in the output

received finally. The output at this stage is 5V and is given to Microcontroller

89S52.


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9.5 PIC CONTROLLER

The PIC Microcontroller board consists of circuits necessary to operate a

Microcontroller with PC interface. The board contains provisions for interfacing 8

analog inputs and 23 Digital level signals. The Description of the circuit is given

below.

9.5.1 Analog inputs

Pin no 2 to 10 can be used to connect any analog signals of range 0-5v.

9.5.2 Digital signals

As mentioned in the circuit the pin outs from the port is taken to a 26 pin

FRC connector through which we can connect our Digital level signals 0 or 5 volts.

9.5.3 Clock

The PIC16F877 can be operated in Four Different oscillator modes. The user

can program two configuration bits FOSC1 and FOSC0 to select one of these four

modes.

*LP - Low Power crystal

*XT - crystal / resonator

*HS - High speed crystal/resonator

*RC - Resistor capacitor

The clock we have used is 10 MHZ which full under HS category.


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9.5.4 MCLR/VPP

This is master clear input pin to the IC. A logic low signal will generate a

reset signal to the microcontroller. So we have tied this pin to VCC for the proper

operation of the microcontroller.

9.5.5 TXD and RXD

TO communicate with the outside world the microcontroller has an inbuilt

USART. The O/P and I/P line from the USART is taken and given to a MAX232

IC for having communication with the PC. Since we have used comport for

interfacing the microcontroller.

9.5.6 VCC and Ground

Pin no 32, 11 are tied to VCC and pin no 31, 12 are grounded to provide

power supply to the chip.

9.6 LIQUID CRYSTAL DISPLAY

Frequently, an 8051 program must interact with the outside world using

input and output devices that communicate directly with a human being. One of the

most common devices attached to an 8051 is an LCD display. Some of the most

common LCDs connected to the 8051 are 16x2 and 20x2 displays. This means 16

characters per line by 2 lines and 20 characters per line by 2 lines, respectively.


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FIGURE 9.4

Fortunately, a very popular standard exists which allows us to communicate

with the vast majority of LCDs regardless of their manufacturer. The standard is

referred to as HD44780U, which refers to the controller chip which receives data

from an external source (in this case, the 8051) and communicates directly with the

LCD.

9.6.1 44780 BACKGROUND

The 44780 standard requires 3 control lines as well as either 4 or 8 I/O lines

for the data bus. The user may select whether the LCD is to operate with a 4-bit

data bus or an 8-bit data bus. If a 4-bit data bus is used the LCD will require a total

of 7 data lines (3 control lines plus the 4 lines for the data bus). If an 8-bit data bus

is used the LCD will require a total of 11 data lines (3 control lines plus the 8 lines

for the data bus).

The three control lines are referred to as EN, RS, and RW.


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The EN line is called "Enable." This control line is used to tell the LCD that

you are sending it data. To send data to the LCD, your program should make sure

this line is low (0) and then set the other two control lines and/or put data on the

data bus. When the other lines are completely ready, bringENhigh (1) and wait for

the minimum amount of time required by the LCD datasheet (this varies from LCD

to LCD), and end by bringing it low (0) again.

The RS line is the "Register Select" line. When RS is low (0), the data is to

be treated as a command or special instruction (such as clear screen, position

cursor, etc.). When RS is high (1), the data being sent is text data which should be

displayed on the screen. For example, to display the letter "T" on the screen you

would set RS high.

The RW line is the "Read/Write" control line. When RW is low (0), the

information on the data bus is being written to the LCD. When RW is high (1), the

program is effectively querying (or reading) the LCD. Only one instruction ("Get

LCD status") is a read command. All others are write commands--so RW will

almost always be low.

Finally, the data bus consists of 4 or 8 lines (depending on the mode of

operation selected by the user). In the case of an 8-bit data bus, the lines are

referred to as DB0, DB1, DB2, DB3, DB4, DB5, DB6, and DB7.

9.6.2 HANDLING THE EN CONTROL LINE

As we mentioned above, the EN line is used to tell the LCD that you are

ready for it to execute an instruction that you've prepared on the data bus and on

the other control lines. Note that the EN line must be raised / lowered before/after

each instruction sent to the LCD regardless of whether that instruction is read or

write text or instruction.


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In short, you must always manipulate EN when communicating with the

LCD. EN is the LCD's way of knowing that you are talking to it. If you don't

raise/lower EN, the LCD doesn't know you're talking to it on the other lines.

Thus, before we interact in any way with the LCD we will always bring the

EN line low with the following instruction:

9.6.2.1 CLR EN

And once we've finished setting up our instruction with the other control

lines and data bus lines, we'll always bring this line high:

9.6.2.2 SETB EN

The line must be left high for the amount of time required by the LCD as

specified in its datasheet. This is normally on the order of about 250 nano seconds

but check the datasheet. In the case of a typical 8051 running at 12 MHz, an

instruction requires 1.08 microseconds to execute so the EN line can be brought

low the very next instruction.

However, faster microcontrollers (such as the DS89C420 which executes an

instruction in 90 nanoseconds given an 11.0592 Mhz crystal) will require a number

of NOPs to create a delay while EN is held high. The number of NOPs that must

be inserted depends on the microcontroller you are using and the crystal you have

selected. The instruction is executed by the LCD at the moment the EN line is

brought low with a final CLR EN instruction.


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9.6.3 CHECKING THE BUSY STATUS OF THE LCD

As previously mentioned, it takes a certain amount of time for each

instruction to be executed by the LCD. The delay varies depending on the

frequency of the crystal attached to the oscillator input of the 44780 as well as the

instruction which is being executed.

While it is possible to write code that waits for a specific amount of time to

allow the LCD to execute instructions, this method of "waiting" is not very

flexible. If the crystal frequency is changed, the software will need to be modified.

Additionally, if the LCD itself is changed for another LCD which, although 44780

compatible, requires more time to perform its operations, the program will not

work until it is properly modified.

A more robust method of programming is to use the "Get LCD Status"

command to determine whether the LCD is still busy executing the last instruction

received. The "Get LCD Status" command will return to us two tidbits of

information; the information that is useful to us right now is found in DB7. In

summary, when we issue the "Get LCD Status" command the LCD will

immediately raise DB7 if it's still busy executing a command or lower DB7 to

indicate that the LCD is no longer occupied.

Thus our program can query the LCD until DB7 goes low, indicating the

LCD is no longer busy. At that point we are free to continue and send the next

command. Since we will use this code every time we send an instruction to the

LCD, it is useful to make it a subroutine.


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9.6.4 INITIALIZING THE LCD

Before you may really use the LCD, you must initialize and configure it.

This is accomplished by sending a number of initialization instructions to the LCD.

The first instruction we send must tell the LCD whether we'll be communicating

with it with an 8-bit or 4-bit data bus. We also select a 5x8 dot character font.

These two options are selected by sending the command 38h to the LCD as a

command. As you will recall from the last section, we mentioned that the RS line

must be low if we are sending a command to the LCD.

9.6.5 CLEARING THE DISPLAY

When the LCD is first initialized, the screen should automatically be

cleared by the 44780 controller. However, it's always a good idea to do things

yourself so that you can be completely sure that the display is the way you want it.

Thus, it's not a bad idea to clear the screen as the very first operation after the LCD

has been initialized. An LCD command exists to accomplish this function. Not

surprisingly, it is the command 01h.

9.6.6 WRITING TEXT TO THE LCD

Now we get to the real meat of what we're trying to do: All this effort is

really so we can display text on the LCD. Really, we're pretty much done.

Once again, writing text to the LCD is something we'll almost certainly

want to do over and over. The WRITE_TEXT routine that we just wrote will send

the character in the accumulator to the LCD which will, in turn, display it. Thus to

display text on the LCD all we need to do is load the accumulator with the byte to

display and make a call to this routine.


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CHAPTER 10

CONCLUSION

Detecting the fault in the underground is more complicated which is

determined by our implementation. The faults like open circuit and short circuit are

found effectively by the system proposed. The underground cable implementation

are developing at a faster rate. Hence the need for the detection of faults are also

increasing. The proposed system detects the underground faults with greater

accuracy using sensor monitoring method. Thus the time for the location of fault in

underground cable is decreased.

10.1 FUTURE SCOPE

The fault location can be more accurate using an RSSI algorithm in Zigbee

so that the distance of fault can be measured.


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REFERENCE

1. “Identification of Fault Locations in Underground Distribution System using

Discrete Wavelet Transform” IEEE 2010 paper by A. Ngaopitakkul, C.

Apisit, C. Pothisarn, C. Jettanasen and S. Jaikhan.

2. “Remote Data Acquisition Using Wireless - Scada System” by Dr. Aditya

Goel & Ravi Shankar Mishra.

3. “A new fault location algorithm using direct circuit analysis for distribution

systems,” IEEE Trans. Power Del., vol. 19, no. 1, pp. 35– 41, Jan. 2004.

4.

“Computerized underground cable fault location expertise,” IEEE Power

Eng. Soc. General Meeting, Apr. 10 – 15, 1994, pp. 376 – 382.


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APPENDIX 1

PIC CONTROLLER CODING

#include

#include "def.h"

#include "adc.c"

#include "delay.c"

#include "delay.h"

#include "usart.c"

#include "usart.h"

unsigned char mvolt,mcurrent1,mcurrent2,mcurrent3;

unsignedint z;

void delay2();

void display(unsigned char val);

voiddisplayser(unsigned char val);

void displayser1(unsigned char val);

void displayser2(unsigned char val);

voidpwmdelay();

void main(void)


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{

unsignedintj,k,l,x;

unsigned char i,adcv,val,temp,ecg,humi;

RBPU=0;

TRISA=0x0f;

TRISB=0X00;

TRISD=0X00;

PORTB=0X00;

TRISC5=1;

init_comms(); // set up the USART - settings defined in usart.h

initlcd();

initadc();

lcdcommand(0x80);

for(k=0;k


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lcdcommand(0x01);

lcdcommand(0x80);

for(l=0;l


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delay1();

lcdcommand(0x28);

delay1();

lcdcommand(0x28);

delay1();

lcdcommand(0x0e);

delay1();

lcdcommand(0x01);

delay1();

lcdcommand(0x02);

delay1();

lcdcommand(0x06);

delay1();

lcdcommand(0x86);

delay1();

lcdcommand(0x80);

delay1();

}

voidlcdcommand(unsigned char value)


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{

/*DATA = cmd;

RS=0;

EN=1;

delay1();

EN=0;

*/

intg,copy;

g=value;

copy=g;

g=((g>>4) & 0x0F);

PORTD= g;

PORTD|=0X20;

delay1();//for(i=0;i


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delay1();

PORTD=0X00;

}

voidlcddisplay(unsigned char value)

{

/*DATA=dat;

RS=1;

EN=1;

delay1();

EN=0;

*/

inth,copy;

h=value;

copy=h;

h=((h>>4) & 0x0F);

PORTD= h;

PORTD|=0XA0;

delay1();

PORTD=0X00;


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h=copy;

h=(h & 0x0F);

PORTD=h;

PORTD|=0XA0;

delay1();

PORTD=0X00;

}

voidlcddelay(void)

{

int i;

for(i=0;i


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int i;

for(i=0;i>4;

if(hb1


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lcddisplay(val1+0x30);

val2= (val%100)/10;


val3 = val%10;


}

voiddisplayser(unsigned char val)

{

unsigned char val1,val2,val3;

int i;

val1= val/100;

putch(val1+0x30);

// lcddisplay(val1+0x30);

delay1();

val2= (val%100)/10;

putch(val2+0x30);


delay1();

val3 = val%10;


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putch(val3+0x30);


delay1();

}

voidpwmdelay(void)

{

int z;

for(z=0;z


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APPENDIX 2

ANALOG TO DIGITAL CONVERTER

void init_a2d(void) //ADC Initialization

{

ADCON0=0x40; // select Fosc/2

ADCON1=0; // select left justify result. A/D port configuration 0

ADON=1; // turn on the A2D conversion module

}

unsigned char read_a2d(unsigned char channel) // reading theanalog channels

{

channel&=0x07; // truncate channel to 3 bits

ADCON0&=0xC5; // clear current channel select

ADCON0|=(channel


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{

unsigned char x,v1,v2,v3,v4,v5;

unsigned char i;

unsigned char rval;

x=read_a2d(ch); // sample the analog value on RA0

v1=x;

v2=v1/100;

putch(v2+0x30);

txs(v2+0x30);

v3=v1%100;

v4=v3/10;

putch(v4+0x30);

txs(v4+0x30);

v5=v3%10;

putch(v5+0x30);

txs(v5+0x30);

}


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APPENDIX 3

LCD

void txs(unsigned char value)

{

DATA=value;

RS=1;

EN=1;

EN=0;

lcddelay();

}

void initlcd(void) // init commands for lcd

{

TRISD=0x00; // Port B as output for LCD

lcdcommand(0x38);

lcddelay();

lcdcommand(0x38);

lcddelay();

lcdcommand(0x38);

lcddelay();


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lcdcommand(0x0c);

lcddelay();

lcdcommand(0x01);

lcddelay();

lcdcommand(0x02);

lcddelay();

lcdcommand(0x80);

}

void lcdcommand(unsigned char value)

{

DATA=value;

RS=0;

EN=1;

EN=0;

lcddelay();

}

void lcddisplay(unsigned char value)

{

DATA=value;


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RS=0;

EN=1;

EN=0;

lcddelay();

}

void lcddelay(void)

{

unsigned int i;

for(i=0;i


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APPENDIX 4

DATA SHEET

Fault Location and Identification for Underground Power Cable Using Distributed Parameter Approach...

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