2. INTRODUCTION
The creation of Uttar Pradesh Power Corporation Ltd. (UPPTCL) on January
14, 2000 is the result of power sector reforms and restructuring in UP (India)
which is the focal point of the Power Sector, responsible for planning and
managing the sector through its transmission, distribution and supply of
electricity.
UPPCL will be professionally managed utility supplying reliable and cost
efficient electricity to every citizen of the state through highly motivated
employees and state of art technologies, providing an economic return to our
owners and maintaining leadership in the country.
3. About 132KV Bharwa Sumerpur Substation
132KV Bharwa Sumerpur Substation is one important substation of UPPTCL. It is
situated at Bharwa Sumerpur U.P .
The whole substation is divided in to two parts – 132 KV Switchyard & 33 KV
Switchyard.
6. LIGHTNING ARRESTOR
A 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.
When a lightning surge (or switching surge, which is
very similar) travels along the power line to the
arrester, the current from the surge is diverted through
the arrestor, in most cases to earth. Lightning
Arrestor
7. CURRENT TRANSFORMER
A current transformer (CT) is used for measurement of
alternating electric currents.
When current in a circuit is too high to apply directly 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.
A current transformer isolates the measuring instruments
from what may be very high voltage in the monitored circuit.
The primary circuit is largely unaffected by the insertion of
the CT. The rated secondary current is commonly
standardized at 1 or 5 amperes. For example, a 4000:5 CT
secondary winding will supply an output current of 5 amperes
when the primary winding current is 4000 amperes.
8. POTENTIAL
TRANSFORMER Potential transformers (PT) (also called voltage transformers
(VT)) are a parallel connected type of instrument
transformer.
They are designed to present negligible load to the supply
being measured and have an accurate voltage ratio and
phase relationship to enable accurate secondary connected
metering.
The PT is typically described by its voltage ratio from
primary to secondary. Standard secondary voltage ratings
are 120 volts and 70 volts, compatible with standard
measuring instruments.
For example, a 600:120 PT would provide an output voltage
of 120 volts when 600 volts are impressed across its primary
winding.
9. 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.
A circuit breaker essentially consists of fixed and moving contacts. These contacts can be
opened manually or by remote control whenever desired. When a fault occurs on any part of
the system, the trip coils of breaker get energized and the moving contacts are pulled apart by
some mechanism, thus opening the circuit.
When contacts of a circuit breaker are separated, an arc is struck; the current is thus able to
continue. The production of arcs are not only delays the current interruption, but is also
generates the heat. Therefore, the main problem is to distinguish the arc within the shortest
possible time so that it may not reach a dangerous value.
10. According to their arc quenching media the circuit
breaker can be divided as-
1. Oil circuit breaker
2. Air circuit breaker
3. SF6 circuit breaker
4. Vacuum circuit breaker
Oil circuit breaker
In oil circuit breaker the fixed contact and moving contact are
immerged inside the insulating oil. Whenever there is a
separation of electric current carrying contacts in the oil,
the arc in circuit breaker is initialized at the moment of
separation of contacts, and due to this arc the oil is vaporized
and decomposed in mostly hydrogen gas and ultimately
creates a hydrogen bubble around the arc. This highly
compressed gas bubble around the arc prevents re-striking of
the arc after electric current reaches zero crossing of the cycle.
11. Air circuit breaker
It may increase the arc voltage by cooling the arc
plasma. As the temperature of arc plasma is
decreased, the mobility of the particle in arc plasma is
reduced, hence more voltage gradient is required to
maintain the arc.
It may increase the arc voltage by lengthening the arc
path. As the length of arc path is increased,
the resistance of the path is increased, and hence to
maintain the same arc electric current more voltage is
required to be applied across the arc path. That means
arc voltage is increased.
Splitting up the arc into a number of series arcs also
increases the arc voltage.
12. SF6 circuit breaker
In such circuit breaker, sulphur hexafluoride (SF6)
gas is used as the arc quenching medium. The SF6 is
an electronegative gas and has a strong tendency to
absorb free electrons.
These circuit breakers are available for
the voltage ranges from 33KV to 800KV and even
more.
132KV SF6 CB
13. Vacuum circuit breaker
Vacuum circuit breakers are circuit breakers which are used to protect medium and
high voltage circuits from dangerous electrical situations. Like other types of circuit
breakers, vacuum circuit breakers literally break the circuit so that energy cannot
continue flowing through it, thereby preventing fires, power surges, and other
problems which may emerge.
The operation of opening and closing of electric current carrying contacts and
associated arc interruption take place in a vacuum chamber in the breaker which is
called vacuum interrupter.
14. ISOLATOR
It is an off-load device.
It disconnects or isolates the circuit from the main power supply.
Even though, isolators is a switch, it is not used as a normal on off switch.
It is used only when the electrical system has to be disconnected from the
main supply, to perform maintenance or related activities, which involve
direct contact with the current carrying components of machinery.
Isolators may provide additional safety features like, when switched off the
trapped charge will be ground through a ground terminal in the isolator.
Isolators are normally placed after the circuit breaker allowing the internal
circuit to be disconnected from the main supply without affecting the
breaker.
15. FUSE
A fuse is a short piece of wire or thin strip which melts when excessive
current through it for sufficient time. It is inserted in series with the
circuit under normal operating conditions; the fuse element is at a
nature below its melting point. Therefore it carries the normal load
current overheating. It is worthwhile to note that a fuse performs both
detection and interruption functions.
BUS COUPLER
The bus coupler consists of circuit breaker and isolator. Each generator
and feeder may be connected to either main bus bar or spar bus bar
with the help of bus coupler. Repairing, maintenance and testing of
feeder circuit or other section can be done by putting them on spar bus
bar, thus keeping the main bus bar undisturbed. Bus coupler is a device
which is used switch from one bus to the other without any interruption
in power supply and without creating hazardous arcs. It is achieved with
the help of circuit breaker and isolators.
16. RELAY
When a failure occurs on any part of the system, it must be quickly
detected and disconnected from the system.
Rapid disconnection of faulted apparatus limits the amount of damage to it
and prevents the effects of fault from spreading into the system.
For high voltage circuits relays are employed to serve the desired function
of automatic protective gear. The relays detect the fault and supply the
information to the circuit breaker.
17. CONCLUSION
We can conclude that electricity plays an important role in our life. We are made
aware of how the transmission of electricity is done. We too came to know about
the various parts of the Substation system.
The Uttar Pradesh Cooperation Limited has got radio communication in
microwave range in order to transmit and receive data with various Substations in
Uttar Pradesh to get reliable transmission and distribution of electricity.