What Is a Potential Transformer?

A potential transformer is used in power metering applications, and its design allows it to monitor power line voltages of the single-phase and three-phase variety. A potential transformer is a type of instrument transformer also known as a VT, or voltage transformer.

Potential transformers are parallel connected, and are designed to read the voltage phase and ratio relationship during metering. One can connect the primary terminals on a potential transformer in two configurations. These configurations include line to line, or line to neutral.

There are three different types of potential transformers, including an electromagnetic type, a capacitor, and an optical. The optical potential transformer s used in conjunction with electrical properties of optical equipment. The capacitor type is used for higher voltages, and the electromagnetic potential transformer is of the wire-round type. In potential transformers, burden and accuracy are combined, as they are dependent on each other. Most potential transformers have smaller cores and capacities when compared to power transformers.

When using a potential transformer, certain quantities need to be scaled prior to use. These include power, voltage, demand and energy. The use of transformers and potential transformers will require some basic electrical wiring knowledge, as well as experience with voltage.