The document discusses MPMKVVCL, a company established by the Government of Madhya Pradesh to undertake electricity distribution activities. Its main objective is to improve efficiency and make the company commercially viable over time while maintaining affordable tariffs for consumers. It then provides details about the key equipment found in a typical 33kV substation, including transformers, circuit breakers, isolators, and protective relays. It describes the functioning and maintenance of these devices.

2. About MPMKVVCL
The Government of Madhya Pradesh vide order dated 1st
July, 02 has
incorporated Madhya Pradesh Poorv Kshetra Vidyut Vitran Company
Limited as a wholly owned Government of Madhya Pradesh Corporations
under the Companies Act, 1956 to undertake activities of distribution
and retail supply for and on behalf of Madhya Pradesh State Electricity
Board in the areas covered by the Commissioner of Jabalpur, Sagar,
Rewa and Shahdol. Go MP proposed a transient phase in which the
assets and liabilities would continue to be serviced by the Board, with
the only operational activities being vested into this new Company.
Madhya Pradesh Electricity Regulatory Commission in the order dated
16th
July, 02 has granted approval to this Operation and Management
arrangement for facilitating the process of reform and reorganization
and bringing in economy and efficiency in the operational activities of
electricity sector.
Objective:- The main objective is to achieve efficiency and to make
necessary changes whenever required in order to make the Company
Commercially viable, progressively self sustainable and less government
dependent and at the same time, balancing the interest of the
consumers in regard to quality of service and economical tariff. The plan
would also include other things like, metering, billing, collection,
identifying the present deficiencies and the improvements to be made,
mapping supply feeders, measurement of energy supplied to feeders
and energy audit, study of losses and scheme for progressive reduction,
reduction in input costs, consumer affairs handling, investment required
for improvement in the distribution system etc.

3. ACKNOWLEDGEMENT
I take this opportunity to thank all the persons out there who helped me out
In the 15 days of training in M.P.M.K.V.V.C.L (O&M) Circle Guna under STM
Division
A special thanks to the DGM of STM Division Mr. NEERAJ DUBEY SIR who
Spare his valuable time from his busy schedule with me and provided
Adequate knowledge about the equipments and the functioning of whole
MPEB circle.
A heartily gratitude to all the workers and employees out there who taught
Me to use different tools.

4. Definition of sub-station:
“The assembly of apparatus used to change some characteristics (e.g. Voltage ac to dc, freq, p.f.
etc) of electric supply is called sub-station”
Sub-Station:
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 any of several other
important functions. Between the generating station and consumer, electric power may flow
through several substations at different voltage levels.
A substation may include transformers to change voltage levels between high transmission
voltages and lower distribution voltages, or at the interconnection of two different transmission
voltages. The word substation comes from the days before the distribution system became grid. As
central generation stations became larger, smaller generating plants were converted to distribution
stations, receiving their energy supply from a larger plant instead of using their own generators.

5. 2
Main equipments in 33 Kv substation :
Power Transformer
Circuit breaker
Isolator
Earthing switch
Lightning arrestor
Busbar
Current transformer
Potential transformer
Protective relay
DC battery set
Capacitor bank
Fire fighting system
Power transformer :
Transformer is used to step down the voltage from 33 kv voltage to 11kv voltage .
Generally 3.15 MVA, 5 MVA, 10 MVA 33/11kv, A / Y transformer are used in 33/11kv s/s.
We can check the RYB side of transformers for which we have to stand face towards LV side and
from neutral give the name RYB.

6. 3
Maintenance of Transformers:
Check Oil level in main tank & OLTC tank.
Check the color of silica gel in breather ;it must be blue in color .if it is turned pink then recondition
it or replace it. Check On load Tap Changer Lower/Raise trail by Local & Remote.
Trip trail by draining oil in Buchholz relay
Check Earth resistance ,provide watering arrangement for earthling pits.
Tight all connections.
Check breakdown voltage of oil. Clean the bushings.
Attend the oil leakages
Note Temperature of Oil & leakage.
TRANSFORMER OIL:
It’s mineral oil obtained by refine crude petroleum. It serves the following purpose.
Provide additional insulation.
Carries away the heat generated in the core & coils.

7. 4
CURRENT TRANSFORMER
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.
Control and protection: when current exceeds the set value it sends the signal to the
relay which senses the faulty condition.

8. 5
POTENTIAL TRANSFORMER
Potential Transformer or Voltage Transformer are used in electrical power system for
stepping down the system voltage to a safe value which can be fed to low ratings
meters and relays. Commercially available relays and meters used for protection and
metering, are designed for low voltage.

9. 6
CIRCUIT BREAKER:
A circuit breaker is the equipment, which can open or close a circuit under normal as well as fault
condition. These circuit breaker breaks for a fault which can damage other instrument in the
station.
It is so designed that it can be operated manually (or by remote control) under normal conditions
and automatically under fault condition.
A circuit breaker is an automatically operated electrical switch designed to protect an electrical
circuit from damage caused by over current or overload or short circuit. Its basic function is to
interrupt current flow after protective relays detect a fault.
WORKING PRINCIPLE OF CIRCUIT BREAKER:
• The Circuit Breaker mainly consist of fixed contacts and moving contacts. In normal “no”
condition of circuit breaker, these two contacts are physically connected tp each other due
to applied mechanical pressure on the moving contacts.
• There is an arrangement stored potential energy in the operating mechanism of circuit
breaker which is realized if switching signal is given to the breaker. The potential energy can
be stored in the circuit breaker by different ways like by deforming metal spring, by
compressed air or by hydraulic pressure.

10. 7
In 33kv substation generally vacuum circuit breaker are used where are quenching medium is
vacuum
Advantage of Vacuum Circuit Breaker
no oil is required for are quenching Least maintenance
Compact size Light in weight
Maintenance of circuit breaker Close/trip through local/remote control
Trip trial through auto closer relay Oiling & greasing of moving parts

11. 8
LIGHTENING ARRESTER
The circuit which is protected from the strokes of lightning with the help of a
protection device is known as lightning arrester. Here the lightning strokes are
nothing but surges with high transient voltage, arcs of isolation, spark, and surge
currents because of lightning, etc. These devices are used to defend the power
systems by forwarding the high voltage surges in the direction of the ground. And
these power systems and over headlines can also be protected by using ground wire
or the earthing from the direct strikes of lightning. The lightning arrester diagram is
shown below.

12. 9
ISOLATOR:
Isolator is a manually operated mechanical switch that isolates the faulty section of
substation. It is used to separate faulty section for repair from a healthy section in
order to avoid the occurrence of severe faults. It is also called disconnector or
disconnecting switch. There are different types of isolators used for different
applications. They are: single break, double break, bus isolator, and line isolator.
The isolator will be a horizontal double break central rotating type with an earth
switch. Isolators and earth switches can be hand operated. Earth switches and
Isolators (in closed position) are designed to withstand thermal effects

13. CONTROL AND RELAY ROOM
The control room has various control panels which shows the information like
incoming power, outgoing power, frequency, time common to all sub-stations,
status of various lines(healthy, faulted, under outage or maintenance), status of
various protective instruments like isolators, circuit breaker, temperature of
various instruments, working tap of transformer etc.
The DAS (Data Acquisition System) is used to accumulate the data received from
various sources.
The protection system is so fast that it can detect a fault within 30 ms and hence
the circuit breaker can be operated within as less as 80 ms. For 400KV side C.B .,
one time auto reclosure is allowed in order to clear the faults automatically.

14. BATTERY ROOM.
The control panels and relays of the sub-station required DC supply of 110 V.
The DC supply is made with the help of battery bank reserve normally kept in a
separate room called battery room
The batteries used in this sub-station are Nickel-Cadmium (NI-Cd) batteries.
These batteries reused due to their advantages like low maintenance, longer life
(15-20 years) etc. Each cell is of 2 V and 300 Ah Capacity.
PROTECTIVE RELAY:

15. METER TESTING LAB: