The document discusses the key components and specifications of the 33/11 kV substation in Hajipur. It provides information on the types and ratings of transformers, circuit breakers, protective relays, insulators, bus bars, isolators, earthing systems, and capacitor banks installed at the substation. Ratings include transformers of 3 MVA capacity, 11 kV incoming and outgoing VCBs of 630A and 800A capacity, and a 160 MVA main bus bar rating. The substation receives high voltage electricity from generating stations and lowers the voltage for local distribution.

1. SUBMITTED BY
Paras Kumar
1407748
SUBMITTED TO
Mr. Satnam Singh Matharu
(HOD of EE Department)

2. About 33/11 kv substation Hajipur

3. Important term related to Hajipur substation
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4. Substation
The assembly of apparatus used to changes characteristics of
the electrical supply is called a substation. Some of the main
operations of substations are:-
• To receive energy and transmitted at high voltage from the
generating stations.
• To decrease the voltage to a value appropriate for local
distribution.
• To change the frequency level.
• To improve the power factor.
• For rectification the voltage.

5. Types of substation on the basics of Service requirement
1) Transformer substation
2) Power factor correction substation
3 ) Frequency changing substation
4) Rectification substation
Types of substation on the basics of construction fetchers
1) Indoor substation
2) Outdoor substation
3) Pole mounted substation
4) Underground substation

6. Transformer
It is a static device which transforms power from one circuit to
another circuit without changing its frequency but may be in different
voltage level with the help of mutual induction between two winding.

7. Working Principle of Transformer

8. Main Constructional Parts of Transformer
1. Primary winding of transformer
2. Magnetic Core of transformer
3. Secondary Winding of transformer
Various types of transformers
1. Power Transformer
2. Instrument Transformer
3. On the basic of working
4. On the basic of structure
5. Auto Transformer

9. Instrument transformers
The Instrument transformers mean currents and voltages
transformer are used for metering and protection purpose.
Types of Instrument transformer
1. Current transformer:- Step-up transformer
2. Potential transformer: -Step-down transformer
Potential transformer
Current transformer

10. Autotransformer
The Autotransformer has only one single voltage winding which
is common for both sides and Same winding is tapped at various
points along its lengths to provide a percentage of the primary
voltages supply across its secondary loads.
Autotransformer

11. Rating of Transformer
1.Power Transformer- 3 MVA-Two
2. Dielectric strength of transformer oil -30 KV.
3.Cooling medium- transformer oil.
4. During full load the temperature will be very
high and may go up to 90°C .
5. flash point of transformer oil. In general it is
more than 140°
6. Capacity of P.T to decreases high voltage to
110V.
7. Capacity of C.T to decreases high current to
5 A

12. Circuit Breaker
1) Make or breaks a circuit either manually or by remote control.
2) Break a circuit automatically under abnormal condition.
4) Its operates under no-load, full load and also in fault conditions.
3) Make a circuit manually or remote control under abnormal
condition.

13. Method of arc extinction
1. Increasing the length of the arc
2. Splitting the arc
3. Reducing the cross-section of the arc
4. Cooling the arc

14. Types of Circuit Breaker
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

15. Air Blast Circuit Breaker
compressed air (18 to 20 kg/cm²) is used

16. Important terms
1.The breaking speed of this circuit breaker is
much higher during operation.
2.Arc quenching is much faster during operation.
3.Requires much less maintenance.

17. Oil Circuit Breaker
Hydrogen gas bubbles surround the arc.

18. Important term
1.The arc temperature may reach up to 5000° K.
2.The oil used here is same as transformer insulating
oil.
3. Dielectric strength of oil -30 KV.
4. It is used only for low voltage up to 11 kv.

19. SF6 Circuit Breaker

20. Important terms
1. High dielectric strength
2.compact in size
3.Noise less operation
4. Small quantity of SF6 gas required

21. Vacuum Circuit Breaker
The vacuum pressure inside a vacuum interrupter is normally
maintained at 10- 6 bar.

22. Circuit Breaker used in Substation

23. Circuit Breaker used in Substation
1.33kV VCB -1250A-Three
2.11kV incoming VCB-630A- Two
3.11kV outgoing VCB-800A- Three
4. Bus coupler VCB -630A- One

24. Protective Relay
It is a device that detects the fault and initiates the operation of
the circuit breaker to isolate the defective section from the rest
of the system.

25. Elements of the protective Relay
1. Sensing element
2. Comparing element
3. Control element

26. Working of protective Relay

27. Insulators
An electrical insulator is a material whose internal electric
charges do not flow and therefore make it impossible to
conduct an electrical current.
Types of Electrical Insulator
1. Pin Insulator
2. Strain Insulator
3. Stay Insulator
4. Shackle Insulator
5.Suspension Insulator
6.Hallow apparatus Insulators

28. Hallow apparatus Insulators
Hallow insulators are employed in chambers of circuit breakers, CTs,
CVTs, bushings, surge arresters.

29. Bus- Bar
The thicker conductor in an electric generating-station ,grid and
sub-station which operating at constant voltage and frequency
are called bus bar.

30. Bus coupler
It is a device which is used to couple one bus to the other
without any interruptions in the power supply

31. Important terms
1. 11kV bus coupler.
2. Capacity of main bus bar- 160MVA

32. Isolator
1. It is a mechanical switch
2.Off load device
3. Rating - 800A
Open isolator

33. Ear thing
1. Safety for Human life
2. Safety for Equipments
3. Over voltage protection
4.Minimize damages in the System etc.

34. Lightning arrester
Such types of electrical device which act as conductor during
abnormal conduction and perfect insulator during normal
conduction are called Lightning arrester.

35. Capacitor bank
1.Connected in parallel
2.For providing the leading power factor
3. For reducing line losses