A current transformer (CT) is a transformer that reduces or multiplies an alternating current (AC). It generates a proportionate current in its secondary to the current in its primary.

Instrument transformers include current transformers, as well as voltage and potential transformers. Instrument transformers reduce huge voltage or current values to small, defined values that measuring instruments and protective relays can handle. Instrument transformers shield measurement and protection circuits from the primary system’s high voltage. A current transformer generates a secondary current that is precisely proportionate to the source current. The primary circuit is not burdened by the current transformer.

Current transformers are the power system’s current-sensing components, and they’re found in generating stations, electrical substations, and industrial and commercial power distribution.

♦ Round Current Transformer Measurements

♦ Rectangle Current Transformer Measurements