Presented By:-
Khustar Alam
Malik sameeullah
Manish Kumar
Manish Kr. Bisherwal

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Introduction
In past, human was the main method for controlling a system.
More recently electricity is used for control and earlier electricity control is based on relays.
The development of low cost computer has brought the most recent revolution.
PLC is a work house of industrial automation.It is important because all production process go through a fixed repetitive sequence of operation that involve logic step and decision.
Used to control time and regulate the sequence.
Need Of PLC
Originally a logical control system hard wired using electronic relay, timer and logical unit.
These system is inflexible.
If need to alter machine configuration then logic system is need to be manually rewired for new application.
This was inflexible and time consuming.
History
In 1970,when mini computers become available.
It is easy to perform switching time delay ad logic in computer program.
To reduce complexity, PLC is developed.
In 1980, with the invention of chip and memory, modern PLC is invented.
Application For PLC in Service Automation
There are many application:
Protection And Control
circuit breaker lockout.
protection relay interface
Automatic Switching
Emergency load shedding.
Feeder automation and fault recovery.
Voltage Regulation Management
Load tap changer control.
Voltage regulation control.
Capacitor control.
Station HMI/Graphical user Interface(GUI)
Interactive real time signal line display.
One line operation and maintenance logic.
Type Of Programming
Ladder Logic (LAD) is a graphical representation of the programming language. The syntax for the instruction is similar to a relay ladder logic diagram.
Statement List (ST) is a textual representation of programming language similar to machine code.
Structure Control Language (SCL) is a PASCAL like programming language which is more suitable for creating complex function.
Ladder Program Basic
The main program in PLC is in LADDER LOGIC. Let us take the following example
represents coil protection.
-I I- represents energize coil switch.
Zones Of Control
Zone 1: Transmission Voltage Breaker Bay Control
Zone 2: Transmission Voltage Bus Tripping & Restoration Control
Zone 3: Transformer Control
Zone 4: Sub-transmission Breaker Bay Control
Zone 5: Sub-transmission Voltage Bus Tripping & Restoration Control
Typical Architecture
The Sequence Of Event Recording (SER) application verifies the protection and control scheme in the event of system operation and allows utility operators to fine- tine the model to further increase system reliability.
Sequence of event recording
Increased systems reliability
Demonstrates the capabilities of a PLC-based solution to perform all application.
Benefits of SER
The benefits of using SER in substation using a PLC-based solution includes:
• Safe and profitable business and operating decisions
• Improved diagnostics
• Ease of Implementation
Recent PLC Detail
Siemens S7 PLC
ABB AC 800M PLC

Prepared By:-
Khustar Alam
Malik Sameeullah
Manish Kumar
Manish Bisherwal

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PLC DISCRIPTION
A programmable logic controller (PLC), also referred to as a programmable controller, is the name given to a type of computer commonly used in commercial and industrial control applications.
INPUT/OUTPUT PORT
PLC have a provision for discrete and continuous signal at a I/O Port
Input port is use to sense the signal
Switches, pushbotton and RTD are used
Analog signal value (0 to 20 mA, 4 to
20 mA, or 0 to 10 V)
I/O is generally 0 and 1
Analog input is converted into digital using A/D converter
MAIN PART(PROCESSOR)
processor is consist of microprocessor, system memory
serial communication port for printer, PLC LAN link
Provision for supply port and external port for I/O
Mounting rack is used to extend PLC
COMMUNICATION GATEWAY
Various Protocol is available for communication
RS 232, Ethernet and PROFIBUS is generally used
The Rs 232 interface is a standard specification of connecting two device
Ethernet refer to the cable. Four type of cabling are commonly used. These are:10Base5, 10Base2, 10Base-T, 10Base-F
LAN use standard Ethernet, twisted pair Ethernet.
PROFIBUS
PROFIBUS is a variety of protocols built on the same field-bus technology bundle.
PROFIBUS networks make use of three separate layers of the OSI Network model
PROFIBUS does not define layers three through six.
Mainly three type of Profibus are used:
Profibus PA(Process Automation),
Profibus DP( Decentralized Periphery)
Profibus FMS( Fieldbus Message Specification)
LADDER LOGIC PROGRAMMING
Exactly similar to an electrical ladder diagram
Normally Open (NO), signal state of contact is 1 then power can flow otherwise power cannot flow.
Normally Closed (NC), signal state of contact is 1 then power cannot flow otherwise power is flow
Implementation of Complex logic function in ladder programming
TIMER AND COUNTER IN LADDER LOGIC
Provision for timers and counter which help to provide delay on output.
Timers have a great industrial application for automation.
Left side of the timer function block are the timer enable contacts.
When contact is closed, it clock is enabled and it starts timing.
It has three output contacts.
When the timer is timed out, DN is set.
The enable bit follow the input enable status.
TT is set when the timer is operating.
PART
PLC working in substation with the help of example
At a generation station, generator is the main equipment
Need to regulate it properly
PLC is easily utilized for this purpose.
Generator connected to the turbine which is rotate by steam
For regulating the speed of alternator and stopping in case of renovation or in any emergency, we need to have a control over a entry of steam
For control the over current, we need to trip some line
In case of fault on main line, we need to activate the main circuit breaker
Temperature regulation of generator by sensing the temp of coil using RTD and convert it to specify signal to produce input at PLC
Relays are connected from PLC so that it reliability increase because now we able to control relay in wide range
GENERATIONSTATION CONNECTION SCHEME
For the control we have input and output connected with a PLC. They are as follow:
INPUT
I0:1, start bottom for start generator.
I0:2, stop bottom for shutdown generator.
I0:3, temp sensor device to sense temperature
I0:4, CT for sense overload and trip line 1
I0:5, CT for sense overload and also trip line 2
OUTPUT
O0:1, motor supply who stem entry
O0:2, input for a relay to trip line 1
O0:3, input for a relay to trip line 2
O0:4, for closing main ckt after generator start
O0:5, for activating relay in cause of ground fault due to which over current is flow
PROGRAM
 Window for writing program
CONCLUSION
PLC is reliable to use in substation
More complex logic develop using software
Easily tackle the case of emergency
Fully automation is possible
Man power requirement reduce