Instrument Transformers

Instrument Transformers

Instrument transformers are essential parts of many electrical metering and relaying systems. The quality of instrument transformers will affect directly the overall accuracy and performance of these systems. Instrument transformer performance is critical in protective relaying since the relays can only be as good as the instrument transformers. They serve two basic functions:  To change …

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Instrument Transformer Testing Procedure

The main tests that are conducted on instrument transformers are as follows: Polarity Test of Instrument Transformers Instrument transformers are marked to indicate the instantaneous direction of primary and secondary currents. Usually, one primary and one secondary terminal are marked with a cross (×) or a dot (•) or a square (■) to indicate the …

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Instrument Transformer

For the measurement of large currents and high voltages in AC circuits, specially constructed accurate ratio transformers are used in conjunction with low range AC instruments. These specially constructed transformers are known as instrument transformers. Types of Instrument Transformer There are two types of instrument transformer. These are: Potential Transformers (PTs) Current Transformers (CTs) These instrument …

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