2. INTRODUCTION OF
SUBSTATION
It is situated at 26°34’2’’N & 80°32’57’’E coordinates
in Dahi Chowki 6.64 km far from Unnao railway station.
Constructed during 1994-98 by CGL.
The whole substation is divided in three parts:
132kv switchyard
400/220kv switchyard
765kv switchyard (Under construction)
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3. INCOMING & OUTGOING LINE OF
SUBSTATION
•Unnao to Lucknow (400KV & 220KV both separate)
•Unnao to Bareily-1 (400KV)
•Unnao to Bareily-2 (400KV)
•Unnao to Agara (400KV)
•Unnao to Panki Kanpur(400KV & 220KV both separate)
•Unnao to Anpara (400KV)
•Unnao to PGCIL Lucknow-1 (400KV)
•Unnao to PGCIL Lucknow-2 (400KV)
•One bus bar for 400/220KV 315MVA ICT-1 & ICT-2 line.
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4. OUTDOOR EQUIPMENT USED IN
SUBSTATION
Two 100MVA 220/132KV transformer
Two 315MVA 400/220KV transformer
Shunt reactor
Capacitor bank
SF6 circuit breaker
Isolators
Lightning arresters
Current transformer
Capacitor voltage transformer
Wave trap
Isolators
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6. Oil pump
Oil pump is
used for
circulating oil
forcelly.
Radiator
plates are
used for
increasing
surface area
for natural air
cooling.
Radiator plates
Earthing
plate 6
7. we use Cooling fans for
forced air cooling of
transformer . Total six fans
are used for each 100MVA
and eight fans are used for
each 315 MVA transformer.
But all fans never start at
same time . It start in pairs .
COOLING FANS
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10. In these photos we can see fogging near transformer due to
operation fire protection system.
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11. BUCHHOLZ RELAY
Buchholz relay is a safety device mounted on some oil-filled power
transformers and reactors. It is used as a protective device sensitive to
the effects of dielectric failure inside the equipment.
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12. OTI & WTI
OTI –oil temp. indicator
measure temp. of oil filled
in transformer. In OTI has
two mercury bulb.
WTI- winding temp.
indicator measure winding
temp of transformer. It has
four mercury bulb.
OTI panel
WTI panel
mercury
bulb
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13. CURRENT TRANSFORMER
In electrical engineering, a current
transformer (CT) is used for
measurement of electric currents.
Current transformers, together
with voltage transformers (VT)
(potential transformers (PT)), are
known as instrument transformers.
When current in a circuit is too high
to directly apply to measuring
instruments, a current transformer
produces a reduced current accurately
proportional to the current in the
circuit, which can be conveniently
connected to measuring and
recording instruments.
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15. A capacitor voltage transformer
(CVT) is a transformer used in
power systems to step-down extra
high voltage signals and provide
low voltage signals either for
measurement or to operate a
protective relay.
The device has at least four
terminals, a high-voltage terminal a
ground terminal and at least one set
of secondary terminals.
CVTs are typically single-phase
devices
CAPACITOR VOLTAGE TRANSFORMER
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17. 1. High Voltage terminal
2. Compensation reactor
3. Intermediate voltage
transformer
4. Ground terminal
5. Ferro-resonance
suppression device
6. Damping resistor
7. Carrier (HF) terminal
(optional)
8. Overvoltage protective
device
9. Secondary terminals
10. Link, to be opened for
test purposes
PRINCIPLE CIRCUIT DIAGRAM OF
CVT
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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.
In this image we can
see a SF6 circuit breaker
with double break
system.
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19. ISOLATORS
An isolators switch are
used to completely de-
energized an electrical
circuit. High-voltage
isolation switches are used
in electrical substations to
allow isolation of apparatus
such as circuit breakers and
transformers, and
transmission lines, for
maintenance.
Isolating rod
Earth link rod
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22. Wave trap
Wave trap are used in
power system for carrier
communication.
It trap the higher
frequency above 50Hz.
It is the effort to utilize
the same transmission line
between two substation for
the purpose of
communications
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24. LIGHTNING ARRESTOR
The overvoltage protection
is obtained by the use of
lightning / surge arresters.
Lightning Arresters or
Surge Arresters are always
connected in Shunt to the
equipment to be protected,
they provide a low
impedance path for the
surge current to the ground.
Mostly in present days
zinc oxide (ZnO) gapless
arresters are in use.
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25. INTERPOSING C.T.
The interposing CTs are used
for Power transformer
Differential Protection
circuit. In a delta/Star Power
transformer, the cts will be
connected star and delta
formation, for eliminating
Zero sequence current on star
side. There will be mismatch
of secondary current , to
maintain equilibrium,
interposing Cts will be
connected to Delta formed
CTs.
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28. SHUNT REACTOR
Shunt Reactor is a thyristor controlled high impedance
transformer.
A stable bus
voltage can be
maintained by
providing
variable reactive
power based on
the bus voltage
deviations due
to the load
variations.
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29. SHUNT CAPACITOR
BANK
Shunt capacitor banks
are used to improve the
quality of the electrical
supply.
provide capacitive
reactive compensation.
Power factor correction.
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