POWER TRANSMISSION

LINE FAULT

IDENTIFICATION AND

LOCATION

ABOUT THE PROJECT

Our project aim is to identify the fault in

the transmission line and find the

location. This is achieved through a

Micro controller, in the Micro controller

we will have the Predefined set values.

We will have the predefined set values

for all the three lines and Look up table

values to find the location

ABOUT THE PROJECT

All the three lines R,Y and B connected

to the CT, Current Transformer. It will

check the incoming current and through

rectifier - Instrument Rectifier Circuit, it

will convert it into Analog value and the

Analog value will be checked with the

Micro controller pre set values.

ABOUT THE PROJECT

Like this all the three lines will be

monitored and if the preset values

exceeds fault will be identified and the

same will be displayed in the LCD. We

will have a three different preset values

for each and every line so the fault line

will be identified individually .

ABOUT THE PROJECT

Similarly to find our the fault location,

reference values will be referred from

the look up table stored in the Micro

controller. The location will be identified

based on minimum to maximum set

values and the same will be displayed in

the LCD

ABOUT THE PROJECT

The lines will be connected to the CT, Current

Transformer and the CT is connected to the

Instrument Rectified Circuit. The Instrument

Rectified Circuit will be connected to the

Micro controller through ADC. LCD unit will

be connected to the Micro controller to

display the fault and location details. The

Micro controller will have the Preset values

and Look up table Reference values.

LIST OF COMPONENTS

Atmel 89C51 Microcontroller

ADC

CT – Current Transformer

Power Supply Unit

PCBs

Instrument Rectifier Circuit

Relay Driver Circuit

SOFTWARE REQUIRED

Keil Software – Assembly Coding

Easy PC – for PCB Design

BLOCK DIAGRAM

R

PHASE

LOAD

LOAD

LOAD

CT1

CT2

CT3

INS

TRU

MEN

T

REC

TIFI

ER

CIR

CUI

T

R &

Neutral

Y &

Neutral

B &

Neutral

ADC

ATMEL

MICRO

CONTROLLER

RELAY DRIVER

CIRCUITRELYAS

TO

LOADS

LCD

DISPLAY

BLOCK EXPLNATION

All the three lines R,Y,B are connected to the corresponding current transformer.

Current transformer measures the amount of current flowing in the particular line.

All the currents are alternating current so we need to convert it into dc.

For that we are using instrument rectifier circuit.

BLOCK EXPLNATION

Output of the instrument rectifier circuit is

dc current which is analog signal.so we

need to convert this analog signal into

digital signal.

So that we are using analog to digital

converter and the output is given to micro

controller

BLOCK EXPLNATION

Controller displays the amount of current in

the corresponding ling in the lcd .

Relay is used to trip the line whenever this

action is required.

Relay driver is used to drive the electro

mechanical relay.

CIRCUIT EXPLANATION

THREE current transformer are connected

with instrument rectifier circuit which

converts the ac to dc current.

Out put of the three rectifier circuit are

connected with analog to digital converter.

Analog to digital converter is connected

with one of the port of the controller.

CIRCUIT EXPLANATION

In this project we are using atmel micro controller.

LCD is connected in one of the port of the controller.

Relay is connected in one of the port pin of the controller.

Relay driver is connected in one of the port pin of the controller.

Power supply unit

Power supply to the circuit is given using

regulated power supply.

Regulated power supply consists of

following components

• Step down transformer

• Bridge rectifier

• Filter

• regulator

STEP DOWN

TRANSFORMER

When AC is applied to the primary winding of the

power transformer it can either be stepped down

or up depending on the value of DC needed.

In our circuit the transformer of 230v/12-0-12v is

used to perform the step down operation where a

230V AC appears as 12V AC across the secondary

winding .

STEP DOWN TRANSFORMER

One alteration of input causes the top of the

transformer to be positive and the bottom

negative.

The next alteration will temporarily cause the

reverse. The current rating of the transformer used

in our project is 2A.

Apart from stepping down AC voltages , it gives

isolation between the power source and power

supply circuitries.

RECTIFIER UNIT

In the power supply unit, rectification is normally achieved using a solid state diode.

A commonly used circuit for supplying large amounts of DC power is the bridge rectifier.

A bridge rectifier of four diodes (4*IN4007) are used to achieve full wave rectification.

Two diodes will conduct during the negative cycle and the other two will conduct during the positive half cycle.

FILTER UNIT

Filter circuits which is usually a capacitor acting as a surge arrester always follow the rectifier unit.

This capacitor is also called as a decoupling capacitor or a bypassing capacitor, is used not only to ‘short’ the ripple with frequency of 120Hz to ground but also to leave the frequency of the DC to appear at the output.

A load resistor R1 is connected so that a reference to the ground is maintained .

C1R1 is for bypassing ripples. C2R2 is used as a low pass filter, i.e. it passes only low frequency signals and bypasses high frequency signals

REGULATOR

The primary purpose of a regulator is to aid the rectifier and filter circuit in providing a constant DC voltage to the device.

Power supplies without regulators have an inherent problem of changing DC voltage values due to variations in the load or due to fluctuations in the AC liner voltage. With a regulator connected to the DC output, the voltage can be maintained within a close tolerant region of the desired output.

IC7805 and 7812 is used in this project for providing +5v and +12v DC supply.

ATMEL CONTROLLER

• The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of Flash Programmable and Erasable Read Only Memory (PEROM).

• The device is manufactured using Atmel’shigh density nonvolatile memory technology and is compatible with the industry standard MCS-51™ instruction set and pin out

FEATURES

•Compatible with MCS-51™ Products

•4K Bytes of In-System Re-programmable Flash Memory –

Endurance: 1,000 Write/Erase Cycles

•Fully Static Operation: 0 Hz to 24 MHz

•Three-Level Program Memory Lock

FEATURES

• 128 x 8-Bit Internal RAM

• 32 Programmable I/O Lines

•Two 16-Bit Timer/Counters

• Six Interrupt Sources

• Programmable Serial Channel

•Low Power Idle and Power Down Modes

CURRENT TRANSFORMER

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.

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

PRECISION RECTIFIER

The CT and PT outputs are relatively very

low when compared with the primary

voltage and current. The outputs of the

CT’s and PT are sine wave in nature. We

must rectify it properly without any loss and

there should be provision for amplification

PRECISION RECTIFIER

For the above mentioned problems we cannot use a DIODE based rectifiers due to following reasons:

1. Diode based rectifiers require a minimum of 1.4V for

its operation.

2. Only 90% efficiency can be achieved .

3. Output can neither be tuned nor amplified.

4. Impedance matching cannot be achieved.

To avoid the above problems we go for Op-Amp based full wave precision rectifiers. We use Op-Amp full wave

Precision rectifier – IC 1458 for our application.

ADC

Features

1. Easy interface to all microprocessors

2. Operates ratio metrically or with 5 VDC or

analog span adjusted voltage reference

3. No zero or full-scale adjust required

4. 8-channel multiplexer with address logic

5. 0V to 5V input range with single 5V power supply

ADC

6. Outputs meet TTL voltage level specifications

7. Standard hermetic or molded 28-pin DIP package

8. 28-pin molded chip carrier package

9. ADC0808 equivalent to MM74C949

10. ADC0809 equivalent to MM74C949-1

LCD

In this project we are using 16x2 lcd. It means LCD

has 2 lines of 16 characters each.

Many other LCDs like 20×2, 24×2, 32×2, 20×4 etc. are

available. Functionally all these LCDs are same .

These displays contains two internal byte-wide

registers, one for command and second for characters

to be displayed.

There are three control signals called R/W, DI/RS and

En.

LCD

LCD stands for Liquid Crystal Display. The most commonly used LCDs found in the market today are 1 Line, 2 Line or 4 Line LCDs which have only 1 controller and support at most of 80 characters.

Instruction Register (IR) and Data Register (DR)

There are two 8-bit registers controller Instruction and Data register. Instruction register corresponds to the register where you send commands to LCD

LCD

e.g. LCD shift command, LCD clear, LCD

address etc. and Data register is used for storing

data which is to be displayed on LCD.

When send the enable signal of the LCD is

asserted, the data on the pins is latched in to the

data register and data is then moved automatically

to the DDRAM and hence is displayed on the

LCD

RELAYRelays are electromagnetic switches, which provides contact between two mechanical elements.

Relays have a coil which works on 12V dc power supply and provides DPDT action as an output. In general relays provide potential free contacts which can be used for universal function like DC, AC voltage switching and to control bigger electrical switch gears.

The electromechanical relays are based on the comparison between operating torque/force and restraining torque/force.

RELAY

The VA burden of such relays are high. The characteristics of these relays have some limitations.

Each relay can perform only one protective function. Such relays are used for simple and less costly protection purposes.

For important and costly equipment installation static relays are preferred.

Protective relaying is necessary for almost every electrical plant and no part of the power system is left unprotected.

RELAYRelays are electromagnetic switches, which provides contact between two mechanical elements.

Relays have a coil which works on 12V dc power supply and provides DPDT action as an output. In general relays provide potential free contacts which can be used for universal function like DC, AC voltage switching and to control bigger electrical switch gears.

The electromechanical relays are based on the comparison between operating torque/force and restraining torque/force.

RELAY

The VA burden of such relays are high. The characteristics of these relays have some limitations.

Each relay can perform only one protective function. Such relays are used for simple and less costly protection purposes.

For important and costly equipment installation static relays are preferred.

Protective relaying is necessary for almost every electrical plant and no part of the power system is left unprotected.

EMBEDDED SYSTEMS

EMBEDDED SYSTEM is a combination of Software and Hardware. An Embedded system is a system, that has a computing device embedded into it.

These are the controllers, processors, arrays or other hardware using dedicated (embedded) logic or programming (code) called “firmware” or a “micro kernel

Embedded systems are designed around a µC which integrates Memory & Peripherals

WHY EMBEDDED SYSTEMS

Avoids lots of Electronics Components

Built in rich Features

Reduces the cost, space

Less Down Time for Maintenance

Probability of Failure is reduced

Easy interface with Computers

CHARACTERISTICS OF AN

EMBEDDED SYSTEM

Sophisticated functionality

Real-Time Operation

Low Manufacturing Cost

Low Power Consumption

Eliminates Necessity of Complex Circuitry

Smarter Products

Smaller Size

User Friendly

State of the Art Technology