2. • Introduction
• Single Line Diagram
•Power Transformer
• A Quick Picture Of How Substation Works
• Lightening Arrestor
• Wave Trap
• Current Transformer
• Potential Transformer
• Circuit Breaker
• Isolator & Earth Switch
• New Instruments
• Conclusion
3. Electric power is produced at the power generating
stations, which are generally located far away from the
load centers. High voltage transmission lines are used to
transmit the electric power from the generating stations to
the load centers. Between the power generating station and
consumers a number of transformations and switching
stations are required. These are generally known as
substations.
Substations are important part of power system and form a
link between generating stations, transmission systems and
distribution systems.
The generation, transmission and distribution system of
electrical power is called the electrical power supply
system.
4. Substation is an assembly of electrical components such as bus-
bars, switchgear apparatus, power transformers etc.
In 400 KV substations, there is three yard:
400 KV yard
220 KV yard
132 KV yard
Some of the important components of substation in above yard
are.
1. POWER TRANSFORMER
2. CURRENT TRANSFORMER
3. CIRCUIT BREAKER
4. POTENTIAL TRANSFORMER
5. BUS BAR
6. LIGHTENING ARRESTERS
7. ISOLATORS
8. EARTH SWITCHES
5.
6.
7. WHAT IS POWER TRANSOFRMER
WORKING PRINCIPLE
PRACTICAL WORKING
MAIN CONSTRUCTION PARTS
PRIMARY WINDING
MAGNETIC CORE
SECONDARY WINDING
8. • TAP CHANGER
• TANK
• CONSERVATOR
• SILICA GEL BREATHER
• BCHHOLZ RELAY
• DOUBLE DIAPHRANGM EXPLOSION
VENT
• OIL LEVEL INDICATOR
• WINDING TEPERATURE INDICATOR
9.
10. Lightning Arrestor
Lightening arresters discharge the
over voltage surges to earth and
protect the equipment insulation
from switching surges & lightening
surges. surge arresters are generally
connected between phase conductor
and ground. In a substation surge
arrester is located at the starting of
the substation as seen from
incoming transmission lines and is
the first equipment of the
substation. Surge arrester are also
provided near the transformer
terminals phase to ground
11. Wave trap is a PLCC (power line
carrier communication)
communication in power system
which block the outer frequency of
other power station these are
installed in switch yard. It is also
known as line trap.
This equipment is installed in the
substation for trapping the high
frequency communication signals
sent on the line from remote
substation and diverting them to
the telecom panel in the substation
control room.
12. A current transformer (CT) is
used for measurement of
alternating electric currents.
Current transformer, together
with voltage VT is known as
instrument transformers.
The lines in substations carry currents in the order of thousands
of amperes. The measuring instruments are designed for low
value of currents. Current transformers are connected in lines to
supply measuring instruments and protective relays.When current
in a circuit is too high to direct apply to measuring instruments, a
CT produces a reduced current accurately proportional to the
current in the circuit, which can be conveniently connected to
measuring and recording instruments.
13. The lines in substations operate at high
voltages. The measuring instruments are
designed for low value of voltages.
Potential transformers are connected in
lines to supply measuring instruments
and protective relays. These
transformers make the low voltage
instruments suitable for measurement of
high voltages.
Potential transformer
14. Circuit breakers are used for
opening or closing a circuit under
normal as well as abnormal
(faulty) conditions.
Different types of CBs which are
generally used are oil circuit
breaker, air-blast circuit breaker,
vacuum circuit breaker and SF6
circuit breaker.
of a short circuit.
SF6 CIRCUIT BREAKER
15. Isolators are employed in substations
to isolate a part of the system for
general maintenance. Isolator
switches are operated only under no
load condition. They are provided on
each side of every circuit breaker.
Earth switch is used to discharge the
voltage in the circuit to earth for
safety. It is located for each incoming
transmission line and each side of the
bulbar section.
Isolators
Earth switch
16. When number of lines operating at
the same voltage levels needs to be
connected electrically, bus-bars are
used. Bus-bars are conductors
made of copper or aluminium, with
very low impedance and high
current carrying capacity.
Different types of bus-bar
arrangements are…
single bus bar arrangements, single
bus-bar with sectionalisation,
double bus-bar arrangements, and
ring bus-bar scheme and etc.
18. Now from this report we can conclude that electricity
plays an important role in our life, we made aware of
how the transmission of electricity is done. We also
came to know about the various parts of the substations
system.
