Equipment of 66Kv Switchyard

 Today will learn something about switchyard.

Basically Switchyard means a collection of electrical equipment, where high voltage electricity is switched using the various components. Electrical switchyard are one of the important parts in a substation where electricity is transferred from one voltage to another from transmission and distribution.

The equipments are as follows :

1. Lightning Arrestor

2. Line side Isolators

3. Metering Current /Potential transformers (CT/PT)

4. Load Side Isolators

5. Post Insulators(PI) :

6. Load Side CT/PT

7. High Voltage Circuit Breakers(HVCB) typically SF6.

8. Transformer

9. Neutral Grounding resistor

10.Overhead Screenguard

Will understand the purpose of each of the equipments.

1.Lightning Arrestor  - We call it as L.A in short form. The purpose of L.A is to protect switchyard from Lightning waves coming in the form of travelling waves with incoming power supply from DISCOM. It provides protection from indirect lightning.

2.Line side Isolators - Purpose of this isolators are to isolate switchyard from DISCOM Incoming Power line while doing maintenance at our end.This isolators are designed to be operated on No-load. This can be operated manually or motorised also depending on design of switchyard.

3. Metering CT/PT - This CT is used to measure current of incoming line , while PT is used to measure voltage of incoming line. Based on both data mater installed calculates the Power consumption. The class of this meters is special type. Normally its 0.2/0.5s type accuracy.

4.Load side Isolators - The purpose of this isolators is to isolate section of our yard premises in order to carry out minor maintainance at our end. Basically its same as mentioed in sr. no.2  but the purpose is different and so it is installed.

5.Post Insulators (PI) - The purpose of this equipment is to provide support to current carrying conductor installed on height and to provide insulation from ground.So depending on voltage level of height it is installed accordingly.

6.Load side CT/PT - This CT/PT is again used to measure power consumption on load side or for the monitoring and protection of Switchyard equipments from Overcurrent/Overvoltage. Its normally of Class1.0 accuracty equipment.

7.HVCB SF6 breaker - The purpose of this breaker is to protect during fault condition and isolate the Power during same.For switchyard above 33Kv SF6 breaker is used.This is normally closed condition.

8.Transformer - The purpose of transformer is to step-down voltage without change in frequency. Its rating depends on design and requirement of company.This transformer has all its protective devices like Bucholz, OTI/WTI temperature,MOG etc;

9.Neutral Grounding Resistor(NGR) - This is basically used to proivde grounding to transformer in case of fault.Again this depends on design of switchyard some may ave and some may not have this equipment. This provide low resistive path during fault and thus protect the equipments and mainly transformer.

10. Overhead Earthscreen - This is basically GI type wire/rope installed cross passing via structure inside switchyard at an height of around 10Metres. The purpose is to provide protection from direct lightning strokes.

Thus the above mentioned is basic information reagrding equipment of Switchyard.