What does a potential transformer (PT) sense?

A potential transformer (PT) is used in electrical systems to sense voltage. Its primary function is to step down high voltages to a lower level that can be safely measured and monitored by standard measuring instruments or protective relays. By doing this, the PT allows for accurate voltage readings while ensuring that personnel do not directly handle high voltage levels.

In a practical application, the output from the potential transformer is a scaled-down version of the voltage from the primary circuit, which can then be used for various control and monitoring purposes in electrical systems. This capability is vital for maintaining operational safety and efficiency within the system.

While options like amps, resistance, and power factor refer to different electrical measurements, they do not pertain to the functions of a potential transformer. Amps measure current, resistance measures opposition to the flow of current, and power factor is related to the phase difference between voltage and current in an AC circuit. Each of these concepts involves different types of measurements and devices designed for their specific applications, which distinguishes them from the primary role of a potential transformer.