This document provides an overview of a 220 KV substation presented by Mohit Kalal. It discusses key components of substations including transformers, instrument transformers, circuit breakers, lightning arresters, and other auxiliary equipment. It describes the purpose and functioning of power transformers, current transformers, potential transformers, circuit breakers, lightning arresters, capacitors, isolators, and earthing equipment. The presentation concludes by discussing the importance of substations for power transmission and the future career prospects for electrical engineers in maintaining and developing substation infrastructure.

1. A
Seminar Presentation
On
220 KV G.S.S,BASNI
Rajasthan Rajya Vidyut Prasaran Nigam Limited
Presented To Presented By
Mohit Kalal

2. Index to talk about
1.Introduction of a substation
2.Transformer and its Various types
3.Power Transformer
4.Instrument Transformer
5.Circuit Breakers
6.Lightning arrester
7.Instruments in the Substation
8.Auxiliary Equipments
9.Earthing
10.Conclusion
11.Future Scope

3. Introduction
● A substation is a part of an electrical generation,
transmission, and distribution system. Substations
transform voltage from high to low, or the vice versa,
or perform any of several other important functions.
● A substation also comprises of various kind of
switching,protection,control equipment &
transformers.

4. Types of Substation
The Electricity after being generated at the power plant is
transmitted through the transmission lines at high voltage
to the substations.
Substation plays a vital role for the Transmission and
Distribution of Electricity.
Transmission substation :
Transmission substation connects two or more
transmission lines.
Distribution substation:
Distribution substation transfers power from transmission
system to the distribution system of an area.

5. Transformer
Electrical power transformer is a static device which
transforms electrical energy from one circuit to another
without any direct electrical connection and with the
help of mutual induction between two windings. It
transforms power from one circuit to another without
changing its frequency but may be in different voltage
level.
A transformer is an essential role playing equipment
for the proper working of G.S.S as it step up or step
down voltage as per need during transmission of
Electricity.

6. Various Types of Transformers
● Power Transformer
● Instrument Transformer
● Current Transformer
● Voltage Transformer

7. Power Transformer
The power transformer is one of those which is used
in electrical substation to convert transmission line
voltage(132 KV, 230 KV, 400 KV etc.) to
distribution line voltage(say 33 KV) and vice versa.
More over power transformers are used to convert
one level of distribution voltage(i.e. 33 KV) to
another level (i.e. 11KV, which is the usual value of
voltage in the distribution feeders).

8. Instrument Transformer
Instrument Transformers are used for
measurement of electrical quantities i.e. voltage,
power factor, frequency and many more.
Basic function of Instrument transformers is to step
down the System voltage and current.
Why Instrument Transformer ??
Measurement of such very large electrical quantities in
the substation is made possible using this instrument
transformers are very popular in modern power system.

9. Current Transformer
Current transformer is used to step down the
current of power system to a lower level to make it
easy to be measured by small rating Ammeter.
A Current transformer has only one or very few
number of primary turns. The primary winding may
be just a conductor or a bus bar placed in a hollow
core . The secondary winding has large number
turns accurately wound for a specific turns ratio.
Thus the current transformer steps up (increases)
the voltage while stepping down (lowering) the
current.

10. Potential Transformer
Potential Transformer are basically step down transformers with extremely accurate turns ratio. Potential
transformers step down the voltage of high magnitude to a lower voltage which can be measured with
standard measuring instrument. These transformers have large number of primary turns and smaller
number of secondary turns.
● Potential transformers are also known as voltage transformers
● Potential Transformer are also Used for the Protection of System.

11. ● Circuit Breaker
A circuit breaker is a switching device that interrupts the abnormal or fault current. It is a
mechanical device that disturbs the flow of high magnitude (fault) current and in additions
performs the function of a switch. The circuit breaker is mainly designed for closing or opening of
an electrical circuit, thus protects the electrical system from damage.
● Relays
A relay is an electromechanical device or switch that is open or close by electrical current when flow through
it. In a relay, a magnetic force relays the effect of one circuit (control-circuit) to other circuit (load-circuit).
Relays work like a very simple remote control switch,

12. Lightning arrester
Lightning arresters are protective devices for
limiting surge voltages due to lightning strikes or
equipment faults or other events, to prevent
damage to equipment and disruption of service.
Also called surge arresters.
Lightning arresters are installed on many different
pieces of equipment such as power poles and
towers, power transformers, circuit breakers, bus
structures, and steel superstructures in substations.

13. LOCATION OF LIGHTING ARRESTORS
The LAs employed for protecting transformers should be installed as close as possible to the transformer.
The electrical circuit length between LA and the transformer bushing terminal should not exceed the limits
given below

14. CAPACITOR BANK
A Capacitor Bank is a group of several capacitors
of the same rating that are connected in series or
parallel with each other to store electrical energy .
The resulting bank is then used to counteract or
correct a power factor lag or phase shift in an
alternating current (AC) power supply.
● Improves the Power factor of the system.
● Increases the Efficiency and Reliability.

15. Insulators
An electrical insulator is a material whose internal
electric charges do not flow freely; very little
electric current will flow through it under the
influence of an electric field. This contrasts with
other materials, semiconductors and conductors,
which conduct electric current more easily. The
property that distinguishes an insulator is its
resistivity; insulators have higher resistivity than
semiconductors or conductors.

16. Wave Traps
Wave traps are equipments commonly found in
substations over 66kV its more of a communication
and control equipment. With more substations
getting automated(using SCADA) presence of wave
traps is more felt.
Rapid exchange of Data and transfer of Message
between substations.

17. BUSBARS
A bus bars is a conducting bar that carries heavy currents to supply several electric circuits.
If the operation bus is a two way bus bar then if any fault occurs in the one iline the other can still
work without any interruption.
One busbar is main busbar & another is spare or auxiliary busbar.

18. Isolators
Isolators are designed to open a circuit under no
load.Its main purpose is to isolate portion of circuit
from the other & is not intended to be opened
while current is flowing in the line.
There are two types of isolators:-
Off load isolators
On load isolators

19. Auxiliary Equipments
The substation comprises of various
equipments some of these form a major part;
● Control Cables
● Boost Charging
● Power Line Carrier Communication
System

20. Earthing
Connecting of an electrical equipment or apparatus
to the earth with help of connecting wire of
negligible resistance is known as “Earthing” or
“Grounding”.
There are two methods of Earthing :
1. Pipe earthing
2. Plate earthing

21. Conclusion
The Electrical engineering is really just not about theoretical its a combined mixture of both and being able
to learn various things at the grid sub station during the training session it was a great learning experience
for me.
I was able to know in depth what happen in real life and how the combine system work to fulfill the
requirement of electricity on a massive scale throughout the year without any interference.
I had an interest in understanding basic engineering work and practicing what has been learnt in the class.
Also, the training was an opportunity for me to increase my human relation both socially and professionally.

22. Future Scope
The future prospects of the EE graduates are very
wide and bright. The demand for environmentally
friendly power generation, more sophisticated
electrical and electronic devices, and cheaper and
smarter products mean there is a lot of work for
Electrical Engineers. There are a wide range of
challenging paths available to an Electrical
engineer.
The areas they can fit in are Design and
Development, Manufacturing, Automation,
Production and Maintenance, Operation and
Control of any equipments or products which work
on electricity.

23. References:-
● Principles of Power Systems by V.K. Mehta
● Electrical Power Systems by C.L. Wadhwa
● https://www.electrical4u.com/
● http://en.wikipedia.org/wiki/Electrical_substation.