This document provides information about an internship at a 132 kV sub-station. It includes: - An introduction to substations and their purpose in transforming voltages for transmission and distribution. - Descriptions of key equipment at the sub-station, including transformers, lightning arrestors, circuit breakers, relays, and the control panel. - Details on types of transformers, lightning arrestors, relays, and circuit breakers used at the sub-station. - Technical specifications of the control panel and relays installed to monitor and protect the sub-station equipment. The main purpose of the 132 kV sub-station is to step down the transmission voltage of 132 kV

1. VOCATIONAL TRAINING
AT
132 KV SUB-STATION
Internship Presentation By
Submitted To
 Dr. Archana Sharma
Assistant Professor
Department of Electrical Engineering
Anurag Attri
Roll No. 2007350200018
राजकीय इंजीनियररंग कालेज, निजिौर
RAJKIYA ENGINEERING COLLEGE, BIJNOR
AICTE APPROVED GOVERNMENT ENGINEERING COLLEGE AFFILIATED TO A.P.J.
ABDUL KALAM UNIVERSITY, LUCKNOW (U.P.)TECHNICAL UNIVERSITY
 Dr. Mohd. Ahmad
Assistant Professor
Department of Electrical Engineering

2. SUB-STATION
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3. CONTENT
Introduction
Single Line Diagram
Transformer
Types of Transformer
Lightning Arrester
Circuit Breaker
Relays
Control Panel
 Conclusion
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4. INTRODUCTION
A substation is a part of an electrical generation, transmission and distribution system.
Substation transform voltage from high to low or the reverse or perform any of several
other functions.
A substation may include transformers to change voltage levels between high transmission voltages and
lower distribution voltages, or at the inter connection of two different transmission voltages.
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6. TRANSFORMER
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7. TRANSFORMER
A transformer is a static electrical device that transfers energy by inductive coupling between its winding
circuits. A varying current in the primary winding creates a varying magnetic flux in the
transformer's core and thus a varying magnetic flux through the secondary winding. This varying magnetic
flux induces a varying electromotive force (emf) or voltage in the secondary winding.
Transformers range in size from thumbnail-sized used in microphones to units weighing hundreds of tons
interconnecting the power grid. A wide range of transformer designs are used in electronic and electric power
applications. Transformers are essential for the transmission, distribution, and utilization of electrical energy.
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8. TYPES OF TRANFORMERS
1. Autotransformer :- Transformer in which part of the
winding is common to both primary and secondary
circuits.
2. Power Transformer :-Transformers being used to
transfer electric energy between the generator and
distribution primary circuits.
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9. TYPES OF TRANFORMERS
3. Capacitor voltage transformer :-Transformer
in which capacitor divider is used to reduce
high voltage before application to the primary
winding.
4. Instrumental transformer:-Potential or
current transformer used to accurately and
safely represent voltage, current or phase
position of high voltage or high power circuits.
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10. INSTRUMENTAL TRANSFORMER ARE OF TWO TYPES
1. Current Transformer :- A current transformer (CT) is a series connected measurement device
designed to provide a current in its secondary coil proportional to the current flowing in its primary.
Current transformers are commonly used in metering and protective relays in the electrical power
industry.
2. Potential Transformer :- Voltage transformers (VT) (also called potential transformers (PT)) are a
parallel connected type of instrument transformer, used for metering and protection in high-voltage
circuits or phasor phase shift isolation. They are designed to present negligible load to the supply being
measured and to have an accurate voltage ratio to enable accurate metering.
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11. A lighting arrester is a device used on electric power transmission and telecommunication system to
protect the insulation and conductors of the system from the damaging effects of lightning.
Types of Lightning Arrester
• Rod arrester
• Horn gap arrester
• Expulsion type lightning arrester
• Valve type lightning arrester
• Silicon Carbide Arrestors
• Metal Oxide Arrestors
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Lightning Arrester

12. RELAYS
 Basic design
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 Small "cradle" relay
Simple electromechanical relay

13. RELAYS
 A relay is an electrically operated switch. Many relays use an electromagnet to operate a switching
mechanism mechanically, but other operating principles are also used. Relays are used where it is
necessary to control a circuit by a low-power signal (with complete electrical isolation between control
and controlled circuits), or where several circuits must be controlled by one signal. The first relays
were used in long distance telegraph circuits, repeating the signal coming in from one circuit and re-
transmitting it to another. Relays were used extensively in telephone exchanges and early computers to
perform logical operations.
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14. TYPES OF RELAYS
1. Induction Relay :- These are the most widely used
relays for protective relaying purposes involving only A.C.
quantities. These relays operate on the simple principle of
split-phase induction motor.
2. Thermal Relay :- These relays operate on the principle
of thermal effects of electric current. Mostly used for
protection of low voltage squirrel cage induction motor.
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15. TYPES OF RELAYS
3. Buchholz relay :- A Buchholz relay is a safety device sensing
the accumulation of gas in large oil-filled transformers, which
will alarm on slow accumulation of gas or shut down the
transformer if gas is produced rapidly in the transformer oil.
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16. TYPES OF RELAYS
4. Over Load Protection Relay :-Electric motors need overcurrent protection
to prevent damage from over-loading the motor, or to protect against short
circuits in connecting cables or internal faults in the motor windings. The
overload sensing devices are a form of heat operated relay where a coil heats a
Bimetallic strip, or where a solder pot melts, releasing a spring to operate
auxiliary contacts. These auxiliary contacts are in series with the coil. If the
overload senses excess current in the load, the coil is de-energized.
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17. TYPES OF RELAYS
 Other Types of Relays are :-
 Latching relay
 Reed relay
 Mercury relay
 Polarized relay
 Ratchet relay
 Coaxial relay
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18. CIRCUIT BREAKER
 A circuit breaker is an automatically operated electrical switch designed to protect an electrical
circuit from damage caused by overload or short circuit. Its basic function is to detect a fault condition
and interrupt current flow. Unlike a fuse, which operates once and then must be replaced, a circuit
breaker can be reset (either manually or automatically) to resume normal operation. Circuit breakers are
made in varying sizes, from small devices that protect an individual household appliance up to
large switchgear designed to protect high-voltage circuits feeding an entire city.
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Types of Circuit Breaker
1. Oil Circuit Breaker
2. Air Blast Circuit Breaker
3. Vacuum Circuit Breaker
4. SF6 Circuit Breaker

19. SF6 CIRCUIT BREAKER
A circuit breaker in which the current carrying contacts operate in Sulphur Hexafluoride or SF6 gas is
known as an SF6 Circuit Breaker.
SF6 has excellent insulating property. SF6 has high electro-negativity. That means it has high affinity of
absorbing free electron. Whenever a free electron collides with the SF6 gas molecule, it is absorbed by that
gas molecule and forms a negative ion.
The attachment of electron with SF6 gas molecules may occur in tow different ways,
1) SF6 + e = SF6 –
2) SF6 + e = SF6 - + F
These negative ions obviously much heavier than a free electron and therefore over all mobility of the
charged particle in the SF6 gas is much less as compared other common gases. We know that mobility of
charged particle is majorly responsible for conducting current through a gas.
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20. CONTROL PANEL
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 Control panel is most important equipment of the substation as it work as shield guard for all substation
equipment's and electrical network. Moreover, these panels are useful to control the flow of electricity as
per the Voltage class and detect the faults in transmission lines.
 In this panel, varieties of numerical & electromechanical relays are installed to provide damage
protection to equipment's. Meters, Semaphore indicators, Control Switches, Indicating lamps, Push
Buttons, Annunciator, Test Blocks and Test Plugs are among of major equipment's installed as per
designing requirements.
 Designing and manufacturing of Control panel depend on the requirement of utilities and these can
broadly be classified as follows;
1. Line Protection
2. Transformer Protection
3. Bus Bar Protection
4. Tie Break
5. Bus Coupler
6. Reactor

21. CONTROL PANEL
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22. TECHNICAL SPECIFICATION OF CONTROL PANEL AND
RELAY
 FEEDER METER- It consists of ammeter (2), voltmeter (2), and solid state buzzer (2).Further ammeter switch,
voltmeter switch and neutral switch are directly connected through feeder panel.
 ANNUNCIATOR- This consists of :-
1. Master trip relay operated
2. Trip circuit
3. Low oil level alarm
4. Over current relay operated
5. Winding temp alarm
6. Earth fault relay operated
7. Differential relay operated
8. Isolator connected indicator
SWITCH BOARD- It consists of :-Bus coupler: it acts as a intermediate switch board which couple two incoming
source generation. A bus coupler is also used in case of fault occurrence. Each time the bus coupler is engaged for
the faulty condition of one side of bus bar so as to provide supply to the feeders from the other side. Thus protecting
the system. 22

23. The main function of the substation is to collect the energy transmitted at high voltage from the
generating station and then reduce the voltage to an appropriate value for local distribution and
gives facilities for switching.
 132 KV Substation is used to step down voltage from 132 KV to 33 KV and the output is
connected to feeder for local utility.
 Substation of rating 132/33 KV Substation is an extra high Voltage substation that implies that
transmission voltage is of 132 KV, and its distribution voltage is 33 KV.
Conclusion

24. THANKING YOU