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1A TRAINING REPORT ON DURGAPUR PROJECTS LIMITEDDURGAPUR,(WEST BENGAL).

By• Ayan Kumar Gon• Arindam Das• Pallabi Pandit• Subrata Das

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2Contents:- 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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3About 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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4Switch YardIn 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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511kV Switching Substation at Water Works, DPLTo 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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633kV Switching Substation at City CentreLocated 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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7132kV Switching Substation at A-B Zone, DPLLocated alongside DPL gate no.-1, the Switching Substation receives two feeder lines directly from DPL

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8TransformerTransformer 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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9Protection 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 breakers3)High-voltage circuit breakers 4) (SF6) high-voltage circuit breakers5)Vacuum circuit breaker 6) Oil circuit breakers7) Thermal magnetic circuit breakers 8) Common trip breakers

Continued…

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10Continued… 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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11Continued.. 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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12Continued.. 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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13Continued.. 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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14Transformer Protection & AccessoriesThere 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 RelayBuchholz 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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15Continued..

Marshalling boxIt 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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16ConductorsIn 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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17Transformer 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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18Auxiliary DC Control Power System Design for SubstationsThe 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.  

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19CONCLUSIONNow 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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THANK YOU ..