33/11 KV Substation | Components Used In Substation

Hello guys, welcome back to my blog. In this article, I will discuss the 33/11 KV substation, what are the components used in the 33/11 KV substation, etc.

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33/11 KV Substation

33/11 KV Substation | Components Used In Substation


33/11KV, Air Insulated substation (AIS), where 33KV-incoming line & 11KV -outgoing line

SUBSTATION: It is stationed where we can control the electrical supply of a particular area. There are different types according to voltage level, constructions, etc.



Firstly every substation has its Single line diagram where all details are denoted like rating of all equipment, connections, places, and locations.

We divide Substation into three parts:

1. Control room: where the operator sited to control substation here alarm is placed he knows every interruption. (Maybe fault, tripping, 33KV breakdown and burning of cables)

2. Battery room: Batteries are connected in series to produce DC supply (maybe 110V or 220V only the control voltage of every substation) supply with a battery charger. It Contains boost or float mode when we want fast charging of batteries to use boost mode if we want slowly charging of batteries to use float mode.

3. Switchyard: it contains the following equipment

01. Power transformer: The transformer is the heart of the electrical system. Its work is to step down the voltage level from 33 to 11 kV.

02. Instrument Transformer: These are the transformer was used for protection & measurement purposes. There are two types of instruments transformer: Current Transformer (CT) and Potential Transformer (PT). Here if we consider 11Kv it is not possible to measure the current by measuring instrument that’s why by using the current Transformer to measure current. The potential transformer is used to measure voltage.


03. Circuit breaker: For making and breaking purpose breaker are used. We can break (cut off) supply of particular feeders by this. Also, breakers are tripped (off) in a faulty condition. Each feeder individual has a circuit breaker. Usually, here we use Air circuit breaker

04. Bus Bar: These are bundled conductors where we can connect several feeders, loads or connections. If there is one Bus bar 11KV on which we can connect Feeder -1, Feeder-2, Feeder-3(It may be the name of villages or particular residency) and so on.

05. Feeders: By using feeders we can control electricity of a particular area.

06. Lightning arrester: Used for protection. Located at incoming line i.e. 33KV one terminal connected to Ground & one is online. When there is lightning stroke fall at that time it discharges from the ground terminal.

07. Capacitor bank: Used to maintain power factor unity due to avoid penalty from the state electricity board. It must be maintained unity.

08. Insulators: Mainly two types of insulators used pin type for up to 11 kV and suspension type for above 33KV

09. Mounting structure: Used to carry conductors and jumpers also for mounting isolators.



10. Station transformer: Used for building lighting as a Backup supply.

11. Cables: They are used to carry electricity from the battery room to feeders, measuring meters, Transformers, control, and relay panels.

12. Isolators: These are acts as a switch. Located forward and backside of a circuit breaker. operates under no-load conditions manually.

Earthing: It is essential for the substation to discharge leakage current. There are two types first is pipe Earthing and second is Plate earthing. Earthing can be made with charcoal, salt, and water. Earthing may be in a grid or individual. Usually, CU or AL used for Earthing but due to the cost of Cu is high we prefer Aluminium.

LT Panels: For lightning of all switchyard purpose LT panels used.

I hope this article may help you all a lot.
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