Surya

Restricted Earth Fault (REF) Protection of Transformer

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Restricted Earth Fault (REF) protection is a special type of protection. This protection scheme is mainly applied to power transformers. This scheme is designed to detect only the internal earth faults of the transformer. It provides highly sensitive and selective protection for internal earth faults. Restricted earth fault protection is a unit protection scheme. REF … Read more

Testing of Gas Insulated Switchgear (GIS)

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Type Tests of Gas Insulated Switchgear Routine Tests on Gas Insulated Switchgear (GIS) The below mentioned tests are performed on complete GIS assembly Below mentioned tests are performed on the individual equivalent like Circuit Breaker: Current Transformer: Potential Transformer: Disconnectors/Isolators: Acceptance Tests of Gas Insulated Switchgear The acceptance tests are the same as factory routine … Read more

Design of Contacts in Vacuum Interrupters

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The article will focus on the contact design of vacuum interrupters. Before discussing the subject, let us consider why a specific design of contacts is required. The simplest form of contact is the butt-type contact, which has a plain and flat surface. This type of contact is suitable for vacuum circuit breakers with a rated … Read more

Testing of a Vacuum Circuit Breaker

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Type Tests for a 36kV Class Vacuum Circuit Breaker (VCB) As per IS: 13118, these type tests include: These tests are intended to ensure that the circuit breakers perform reliably, safely, and efficiently under various operating conditions. Routine Tests for a 36kV Vacuum Circuit Breaker (VCB) As per IS: 13118, the routine tests include the … Read more

Line Differential Protection

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Before entering the topic of line differential protection, or simply differential protection of a transmission line, we shall first recall our concept of differential protection. Actually, the differential protection used for a transmission line is called line differential protection. We have already heard about the differential protection of transformers, busbars, etc. The same principle is … Read more

Core Balance CT or Core Balance Current Transformer (CBCT)

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core balance ct

We also refer to the Core Balance Current Transformer or Core Balance CT (CBCT) as Working Principle of Core Balance CT (CBCT) A Core Balance Current Transformer (CBCT) is a special type of current transformer. Specifically, it works on the principle of imbalance detection. It monitors the imbalance current of a three-phase cable system. When … Read more

Ferroresonance in Potential Transformer or PT or VT

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As the name suggests, ferroresonance is a resonance phenomenon related to iron. Ferro means ‘iron’. Before understanding the ferroresonance, let us recall the concept of resonance first. Suppose, we have a series RLC circuit, across which a voltage source is connected. Say a current I flowing through the circuit. VL is the voltage developed across … Read more