The document is a training report on the Durgapur Projects Limited power facilities in West Bengal, India. It discusses the company's various substations including 11kV, 33kV, and 132kV switchyards. It describes the transformers and protection systems used, including circuit breakers, relays, insulators, and lightning arresters. The report also covers transformer protection devices, conductor types, transformer testing procedures, and the auxiliary DC power system design for the substations. In conclusion, it discusses the importance of electricity transmission and provides an overview of substation systems.

1. A
TRAINING
REPORT ON
DURGAPUR PROJECTS LIMITED
DURGAPUR,
(WEST BENGAL).
By
• Ayan Kumar Gon
• Arindam Das
• Pallabi Pandit
• Subrata Das
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2. Contents:-
 About DPL
 Switch Yard( 11kV, 33kV, 132kV)
 Transformer
 Protection Systems for Sub-Station
(1.Circuit Breaker, 2.Types of Circuit Breakers used, 3.Relays,
4.Types of Relays used , 5. Insulators, 6. Isolators, 7. Lightning Arresters )
 Transformer Protection
(1. Buchholz Relay, 2. Conservator and Breather ,3. Marshalling box ,4. Fuse)
 Conductors
 Transformer Testing
 Auxiliary DC Power System Design for Sub-Station
 Conclusion
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3. About DPL-Overview
• Incorporated on 6th September,1961. Govt. of West Bengal Undertaking
• Thermal Power Plant. A total of eight units of different capacities have an aggregate 701-mega
watt of installed capacity
• Consists of Coke Oven Batteries, By-products Plant, Gas Grid Project, Thermal Power Plant
and Water Works
• Generation of power and its distribution at 11KV in its licensed area at Durgapur and
transmission of surplus power to WBSEB & WBSEDCL
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4. Switch Yard
In DPL there are three different KV bus bars present
• 33KV
• 132 KV
• 220KV
33kv feeders go to two substation:-
One is near Barrage at Bankura & another is near coal belt region.
132kv feeders go to three substations of DPL. The substations are:-
• A-Substations(FCI)
• B-Substations(near MAMC)
• C-Substations(Durgapur Chemicals)
220kv feeders go to Bidhannagar substations
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5. 11kV Switching Substation at Water
Works, DPL
To supply industrial and drinking water to the residents of DPL township, the company
maintains its captive water storage facility. It has its own water treatment plant. While
water pumping capacity remains at 35 million gallons per day (MGD), the water
treatment capacity has been augmented by 6 MGD to 41 MGD. It also houses a 11kV
Switching substation alongside a transformer workshop.
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6. 33kV Switching Substation at City
Centre
Located near to the City Centre Bus Stand, the Switching Substation supplies power to
Junction Mall, Webel, Suhatta, SAIL, and Village nearby. It converts 33kV to 11kV or
directly switches the 33kV supply line coming from two feeder.
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7. 132kV Switching Substation at A-B
Zone, DPL
Located alongside DPL gate no.-1, the Switching Substation receives two feeder lines
directly from DPL
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8. Transformer
Transformer is a static machine, which transforms the potential of alternating current at
same frequency. It means the transformer transforms the low voltage into high voltage &
high voltage to low voltage at same frequency. It works on the principle of static
induction principle.
Types of transformers seen:-
• Power Transformer
• Instrument Transformers
1. Current Transformer
2. Potential Or Voltage Transformer
• Auto Transformers
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9. Protection System
 Circuit Breakers:
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.
 Type of circuit breaker:
1)Low-voltage circuit breakers 2)Magnetic circuit breakers
3)High-voltage circuit breakers 4) (SF6) high-voltage circuit breakers
5)Vacuum circuit breaker 6) Oil circuit breakers
7) Thermal magnetic circuit breakers 8) Common trip breakers
Continued…
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10. Continued…
 Relay
A relay is an electrically operated switch. Many relays use an electromagnet to
mechanically operate a switch, but other operating principles are also used, such
as solid-state relays
 Relays used in controlling panel of substation
• Differential Relay
• Over Current Relay
• Earth Fault Relay
• Tripping Relay
• Auxilliary Relay
Continued…
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11. Continued..
 Insulators
An electric insulator is a material whose internal electric charges do not flow freely ,and therefore
make it very hard to conduct an electric current under the influence of an electric field.
• Pin Type
• Suspension Type
• Strain Type
• Shackle Type
Continued…
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12. Continued..
 ISOLATOR:
• Isolator is basically a no load switch designed to operate under no load condition
• Isolators used in power system are generally three pole isolators having identical
supports
• The isolators are “Horizontal Breaker Type”.
Continued…
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13. Continued..
 LIGHTNING ARRESTER:
• Lightning Arrester are usually connected between phase and ground of the power plant to
protect the equipment from sudden over voltages caused by lightning or some other reasons
• Lightning arrester consists of low resistor and gap elements. Resistor elements consist of
nonlinear resistors
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14. Transformer Protection & Accessories
There are many protection devices used to protect a power
transformer. The factors governing the protection scheme are its size,
importance and location of the transformer.
Buchholz Relay
Buchholz relay is a safety device mounted on some oil-filled power
transformers and reactors, equipped with an external overhead oil
reservoir called a conservator. The Buchholz Relay is used as a
protective device sensitive to the effects of dielectric failure inside the
equipment.
Conservator and Breather
A conservator is used to maintain the oil level up too predetermined
value in the transformer main tank by placing it above the level of
the top of the tank. Breather is connected to conservator tank for the
purpose of extracting moisture as it spoils the insulating properties
of the oil.
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15. Continued..
Marshalling box
It has two meter which indicate the temperature of the oil and
winding of main tank.
FUSE:
A fuse is a short piece of wire or thin strip which melts when
excessive current through it for sufficient time
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16. Conductors
In physics and electrical engineering, a conductor is an object or type of material which
permits the flow of electric charges in one or more directions.
Types of conductors used in 220kV substations are:-
• a) AAC -> All Aluminium Conductors
• b) ACSR -> Aluminium Conductor Steel Reinforced
• c) ACAR -> Aluminium Conductor Alloy Reinforced
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17. Transformer Testing
For confirming the specifications and performances of an electrical power transformer it has
to go through numbers of testing procedures. The transformer testing performed before
commissioning the transformer at site is called pre-commissioning test of transformer. These
tests are done to assess the condition of transformer after installation and compare the test
results of all the low voltage tests with the factory test reports.
 Transformer Ratio Test
 Magnetic Balance Test
 Short Circuit Test
 Dielectric Test
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18. Auxiliary DC Control Power System
Design for Substations
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The most critical component of a protection, control and
monitoring (PCM) system is the auxiliary dc control power
system. Failure of the dc control power can render fault
detection devices unable to detect faults, breakers unable
to trip for faults, local and remote indication too become
inoperable, etc. In many cases, the dc system is not redundant,
which makes reliability an extremely important consideration
in the overall design.

19. CONCLUSION
Now from this report 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.
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