Distance Protection

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

R CT1
PHASE INS
LOAD TRU
R& MEN
Neutral T
REC ADC
TIFI
CT2 ER
LOAD
CIR
CUI
Y& T
Neutral

CT3
LOAD

B&
Neutral

ATMEL
MICRO
LCD CONTROLLER
DISPLAY

TO
LOADS
RELAY DRIVER
RELYAS CIRCUIT

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’s
high 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

RELAY
Relays 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 C
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

Distance Protection

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