Its overview of electrical power substation, like what are the things are inside and what are the use of their inside a power substation.

1. Overview of Power
Substation

2. Table of Content
➢ Objective
➢ Introduction
➢ Type of Substation
➢ Supply line
➢ Transformer
➢ Bus bar
➢ Switchgear
➢ Protective Devices
➢ Out coming Feeders
➢ Switching Apparatus
➢ Conductor
➢ Insulator
➢ Lightning Arrester
➢ Surge Arrester
➢ Grounding
➢ Battery Bank
➢ Capacitor Bank
➢ Communication
➢ HVAC System
➢ Fire fighting System
➢ Facility

3. Objective
This programmed is designed to have
overview on Electrical Power
Substation and it’s various types and
equipment or machines and their
fundamentals

4. Introduction
A substation is a part
of an electrical
generation,
transmission, and
distribution system.
Substations transform
voltage from high to
low, or the reverse, or
perform several other
important functions. Typical Picture of Power substation

5. Type of Substations
The substations may be classified in numerous ways, such as by
nature of duties, operating voltage, functions, importance, and
design.
➢ Classification based on function :-
 Step-up Substation
 Step-down Substation
 Switching Substation
 Distribution Substation
 Sulfur Hexafluoride Substation (SF6) GIS

6. Type of Substations
A substation based on it’s function further can be sub
categorized based on by construction or arrangement. There
are some example of sub categorized substation based on
their construction below.
➢ Classification based on Construction:-
 Outdoor Substation
 Indoor Substation
 Underground Substation

7. Step-up Substation
➢ A step-up transmission substation
receives electric power from a
nearby generating facility and
uses a large power transformer
to increase the voltage for
transmission to distant locations.
➢ These substation further can be
sub categorized based on their
construction as per requirement
such as Indoor, Outdoor, Gas
Insulated, Under Ground, Pole
Mounted.
Outdoor Step-up Transmission
Substation

8. Step-down Substation
➢ The step-down substation can change
the transmission voltage to a sub
transmission voltage, usually 69 kV
by using step-down transformer.
➢ The sub transmission voltage lines can
then serve as a source to distribution
substations.
➢ Step-down transmission substations
are located at switching points in an
electrical grid.
➢ These substation also further can be
sub categorized based on their
construction as per requirement such
as Indoor, Outdoor, Gas Insulated,
Under Ground, Pole Mounted.
Step-down outdoor Substation

9. Switching Substation
➢ A switching station is a
substation without transformers and
operating only at a single voltage
level.
➢ Switching stations are sometimes
used as collector and distribution
stations. Sometimes they are used
for switching the current to back-up
lines or for parallelizing circuits in
case of failure.
➢ A switching station may also be
known as a switchyard, and these
are commonly located directly
adjacent to or nearby a power
station.
Switchyard or Switching Substation

10. Distribution Substation
➢ Distribution substations are
located near to the end-users.
➢ Distribution substation
transformerschange the
transmission or sub transmission
voltage to lower levels for use by
end-users.
➢ From here the power is
distributed to industrial,
commercial, and residential
consumers.
Small Out Door Distribution
Substation

11. Gas Insulated Substation (SF6) GIS
➢ A gas insulated substation (GIS) is
a high voltage substation in which
the major structures are contained in
a sealed environment with sulfur
hexafluoride SF6 gas as the
insulating medium.
➢ The clearance required for phase to
phase and phase to ground for all
equipment is much lower than that
required in an air insulated
substation.
➢ Although the initial cost of building a
GIS is higher than building an air
insulated substation, the operation
and maintenance costs of a GIS are
less.
Indoor GIS

12. Supply line
➢ Substation is connected to a
transmission system via at least one
supply line, which is often called a
primary feeder.
➢ A supply line can be an overhead line
or an underground feeder, depending
on the location of the substation,
underground cable lines mostly used in
urban areas and overhead lines in
desert or open area.
➢ Supply lines are connected via high
voltage disconnecting switches in order
to isolate lines from substation to
perform maintenance or repair work.
Supply Line or Transmission Line

13. Transformer
➢ A transformer is an electrical
device that transfers electrical
energy from one coil called
primary coil to other coil
secondary coil
through electromagnetic
induction .
➢ The coil connected to incoming
voltage called primary coil
while the coil connected to the
outgoing coil called
secondary coil
➢ Transformers are used to
increase or decrease the
alternating current in electric
power applications.
Typical Diagram of Electrical
Transformer

14. Type of Transformer
There are various type of transformer based on
their functions and use.
 Power transformer
 Service Transformer
 Voltage Transformer (PT - Potential Transformer)
 Current Transformer(CT - Instrument Transformer)

15. Power Transformer
Power transformers are
used in the high voltage
transmission network to
step up and step down
the voltage.
These transformers are
generally used for the
purpose of transmission
of heavy voltage and
rated in 69kva,115kva,
270kva,380kva etc.
Typical picture of Power
Transformer

16. Distribution Transformer
➢ A distribution transformer or
service transformer is a
transformer that provides the
final voltage transformation
in the electric
power distribution
system, stepping down the
voltage used in
the distribution lines to the
level used for lighting or
utility purpose in power
substation.
Typical picture of Service transformer or
distribution Transformer

17. Voltage Transformer
➢ Potential transformer is quite
similar to the current transformer,
but it is used for taking samples
of high voltages of a system for
providing low-voltage to the
relays of protection system and
also to the low-rating meters for
voltage measurement.
➢ From this low-voltage
measurement, the actual system’s
high voltage can be calculated
without measuring high voltages
directly to avoid the cost of the
measurement system. Potential Transformer or
Voltage transformer

18. Current Transformer
➢ Current transformeris used for the
measurement of the alternating
current by taking samples of the
higher currents of the system.
➢ These reduced samples are in
accurate proportionswith the
actual high currents of the system.
➢ These are used for installation and
maintenance of the current relays
in substations for protection
purpose which are normally have
low-current ratings for their
operation.
Current Transformer

19. Bus bar
➢ Bus bars also called buses can be
found throughout the entire power
system, from generation to industrial
plants to electrical distribution boards.
➢ Bus bars are used to carry large
current and to distribute current to
multiple circuits within switchgear or
equipment.
➢ Originally, bus bars consisted of
uncovered copper conductors
supported on insulators
➢ Bus bar's conductors and current-
carrying parts can be either copper,
aluminum, or copper alloy rated for
the purpose.
Copper and aluminum bus bar

20. Switchgear
➢ Switchgear is a general term
covering primary switching and
interrupting devices together with its
control and regulating equipment.
➢ Power switchgear includes breakers,
disconnect switches, main bus
conductors, interconnecting wiring,
support structures with insulators,
enclosures, and secondary devices
for monitoring and control.
➢ Power switchgear is used throughout
the entire power system, from
generation to industrial plants to
connect incoming power supply and
distribute power to consumers. High Voltage Switchgear

21. Switchgear
➢ One of the basic functions of switchgear
is protection, which is interruption of
short-circuit and overload fault currents
while maintaining service to unaffected
circuits. Switchgear also provides isolation
of circuits from power supplies.
Switchgear is also used to enhance
system availability by allowing more than
one source to feed a load.
➢ switchgear has two types of component
1.Control systems - control panels, current
transformers, potential transformers,
protective relays, and associated
circuitry, that monitor, control, and protect
the power conducting components .
➢ 2. Power conducting components- such as
switches, circuit breakers, fuses, and
lightning arrestors, that conduct or
interrupt the flow of electrical power
Switchgear System Metering, Protective
and monitoring Device

22. Metal-Clad Switchgear
➢ Metal-clad switchgears are
commonly used throughout the
industry for distributing supply
voltage service above 1,000 V.
➢ The primary voltage breakers
and switches are mounted on a
removable mechanism to allow
for movement and proper
alignment.
➢ All live parts are enclosed within
grounded metal compartments
➢ Switchgear consist metering and
protective device in it such as
protective relay, watt meter,
ampere meter volt meter etc.
Metal Clad Switchgear

23. Protective Device
➢ The devices that are used to
protect the power systems from
faults are called protection
devices.
➢ Advantages of protected devices
with these three basic components
include safety, economy, and
accuracy
➢ There are three parts of protective
devices:
 Instrument transformercurrent
or potential (CT or VT)
 Relay
 Circuit breaker
Combination of Protection device
(Digital multifunction relay)

24. Relay
➢ A protective relay is a device
designed to trip a circuit breaker
when a fault is detected and in
abnormal operating conditions
such as over-current, over-voltage,
reverse power flow, over-
frequency, and under-frequency.
➢ Electromechanical protective relays
operate by electromagnetic
induction.
➢ protective relays have well-
established, selectable, and
adjustable time and current or
other operating parameter
characteristics.
Numeric Multifunction
relay
Electromechanical relay

25. Out coming Feeders
➢ A number of out coming feeders
are connected to the substation
bus to carry power from the
substation to points of service
➢ Feeders can be run overhead
along streets, or beneath streets,
and carry power to distribution
transformersat or near consumer
premises.
➢ The feedersbreaker and isolator
are part of the substation low
voltage switchgear and are
typically the metal-clad type.
Out Coming Feeder

26. Switching Apparatus
In Electrical power Substation switching apparatus are needed
to connect or disconnect elements of the power system to or
from other elements of the system. Switching apparatus
includes.
➢ Disconnector
➢ Fuses
➢ Circuit Breakers

27. Disconnector or Isolator
➢ A disconnecter or disconnect
switch or isolator switch is used to
ensure that an electrical circuit is
completely de-energized for
service or maintenance.
➢ High-voltage isolation switches
are used in electrical substations
to allow isolation of apparatus
such as circuit breakers,
transformerand transmission
lines, for maintenance.
➢ Disconnectors can be operated
either manually or automatically.
Manually Operated
Disconnector
Automatic knee type
Disconnector

28. Fuses
➢ a fuse is an electrical safety device
that operates to provide over current
protection of an electrical circuit.
➢ Its essential component is a metal wire
or strip that melts when too much
current flows through it, thereby
interrupting the current.
➢ It is a sacrificial device, once a fuse
has operated it is an open circuit, and
it must be replaced or rewired,
depending on type.
➢ A fuse is an automatic means of
removing power from a faulty system
often abbreviated to ADS (Automatic
Disconnection of Supply).
High Voltage Fuse

29. Circuit Breaker
➢ A circuit breaker is an automatically operated electrical
switch designed to protect an electrical circuit from
damage caused by over current, Fault, Short Circuit etc.
➢ There are various types of circuit breakers which are
based on their operation voltage level like low voltage
circuit breakers, medium voltage circuit breakers and
high voltage circuit breakers. High voltage circuit
breakers are used in power substations.
 Oil Circuit breakers (OCB)
 Air blast Circuit breakers (ACB)
 Gas Insulated Circuit breakers (SF6)
 Vacuum Circuit Breakers (VCB)

30. Oil Circuit Breaker
Oil circuit breaker or
OCB is types of circuit
breakers where oil is
used as arc quenching
media as well as
insulating media
between current
carrying contacts and
earthed parts of
the breaker. The oil used
here is same as
transformer
insulating oil.
Oil Circuit Breaker

31. Air Blast Circuit breaker
➢ This type of circuit breakers, is
those kind of circuit
breaker which operatesin air at
atmospheric pressure
➢ Air blast circuit breaker used
compressed air or gas as the arc
interrupting medium.
➢ In the air blast circuit
breaker compressed air is stored
in a tank and released through a
nozzle to produce a high-velocity
jet. this is used to extinguish the
arc.
➢ Air blast circuit breakers are
used for indoor services in the
medium, high voltage
Air Blast Circuit Breaker Actual Picture

32. Vacuum Circuit Breaker
➢ A breaker in which vacuum is
used as an arc extinguish medium
is called a vacuum circuit
breaker.
➢ In this circuit breaker, the fixed
and moving contact is enclosed in
a permanentlysealed vacuum
interrupter. The arc is extinguish
as the contacts are separated in
high vacuum.
➢ Vacuum circuit breaker has a
high insulating medium for arc
extinguish as compared to the
other circuit breaker.

33. SF6 Circuit Breaker
➢ A circuit breaker in which
SF6 under pressure gas is used to
extinguish the arc is called
SF6 circuit breaker. SF6 gas has
excellent dielectric, arc quenching,
chemical and other physical
propertieswhich have proved its
superiority over other arc
quenching mediums such as oil or
air.
➢ SF6 is colorless, odorless, non-
toxic, and non-inflammable gas.
➢ It has high thermal conductivity
better than air and assists in better
cooling current carrying parts.
SF6 Circuit Breaker

34. Conductor
An
electrical conductor is a
substance in which allow
electrical charge to
move, usually electrons
move easily from atom
to atom with the
application of voltage
which is called electric
current. Copper, silver,
iron aluminum are the
example of electrical
conductor.
Conductor

35. Insulator
➢ The material which does not allow
free movement of electrons or
electric charge is called as an
insulator.
➢ Hence, insulators resist electricity with
their high resisting property.
➢ Insulators are used for insulation
purpose while erecting electric poles
with conductors to avoid short circuit
and for other insulation requirements.
➢ There are different types of
insulators such as suspension type,
strain type, stray type, shackle, pin
type and so on.
Different Type of Insulators

36. Lightning Arrester
➢ lightning arrester is a device used
on electrical power systems and
telecommunications systems to
protect the insulation and conductors
of the system from the damaging
effects of lightning.
➢ The typical lightning arrester has a
high-voltage terminal and a ground
terminal.
➢ Whenever light surges occur then, a
high-voltage pass through these
electrical components causing
damage to them Therefore, to avoid
this difficulty, lightening arresters are
placed to pass the entire lightening
surges to earth.

37. Surge Arrester
➢ A surge arrester is a device to
protect electrical equipment from
over-voltage transients caused by
external (lightning) or internal
(switching) events.
➢ Surge arrestor gives the protection
against surge currents or voltages in
a circuit.
➢ Surges can be produced because of
short circuit, lightning, sparking etc.
➢ A surge arrestor can also be used as
a lightning arrestor but a lightning
arrestor can't be used as a surge
arrestor in case of short circuits.
Surge Arrester

38. Grounding
➢ Grounding is an important aspect of
every substation. The function of a
grounding system is to ensure the
safety of personnel and the public,
to minimize hazard from transferred
potential, to protect equipment, to
provide a discharge path for
lightning strikes, and to provide a
low-resistance path to ground.
➢ A good grounding system has a low
resistance to remote earth to
minimize the ground potential rise
➢ In order to a grounding design to be
safe, it needs to provide a way to
carry the electric currents into the
ground under both normal and
faulted conditions.
Substation Grounding System

39. Battery Bank
➢ In Substations we use battery bank to
provide an uninterrupted & reliable
power supply to control the switch
gears & Monitor the status of Feeders
in case of power failure. and the
Operations of breakers, relays,
communication system an emergency
lights.
➢ Battery banks in substation for
switchgear and control applications
are made up of many cells. These cells
are typically wired in series to
achieve a desired voltage and may
also be wired in parallel to achieve
additional ampere capacity. Substation Battery Bank

40. Capacitor Bank
➢ Normally capacitor bank is
used in distribution
Substation to control the
level of the voltage
supplied to the consumer by
reducing or eliminating the
voltage drop in the system
caused by inductive
reactive loads by improving
power factor.
Capacitor Bank

41. Communication System
➢ Power-system automation is the
act of automatically controlling
the power system via
instrumentation and control
devices.
➢ Substation automation refers to
using data from Intelligent
electronic devices (IED), control
and automation capabilities
within the substation, and control
commands from remote users to
control power-system devices.
Power Communication System

42. HVAC System
➢ Substationsrequire special
attention to ventilation in order to
dissipate heat losses from
electrical equipment. Wherever
possible, Forced ventilation
should be used where natural
ventilation is not practicable
forced ventilation means fan(s)
HVAC System must be installed
➢ The ventilation must be sufficient
to maintain a maximum room
temperature of 35 degrees
Celsius. HVAC system and Equipment

43. Fire Fighting System
➢ Substations contain components
and materials that constitute a fire
risk. And due to overheat or arcing
its cause fire causing dangerous
situation to the personnel and
property.
➢ For preventing fire, fire systems
are installed in substations on the
sensitive area which give signal or
alarm in case of fire such as fire
alarm, water sprinkler, smoke
detector heat detector.
➢ Not all possible fire protection
measures are necessary for every
substation
Typical fire fighting system

44. Facility
The substation building are
surrounded by the fence or
concrete wall to prevent the
unauthorized person or
animals to get in and have
facility of washrooms, drinking
water, parking workshop for
small maintenance work and
some distribution substation
premises have residential
compound for it’s staff as
needed.
Typical substation premises

45. Thank You

46. Presented By
Emran Ali