What is the purpose of a potential transformer (PT)?

The purpose of a potential transformer (PT) is to reduce high voltages to a measurable level for instrumentation. This device is critical in electrical systems, especially in transmission and distribution, where voltages can be extremely high. By stepping down the voltage to a safer, lower level, a PT allows for accurate measurement and monitoring with standard measurement equipment, such as voltmeters and relays, without exposing the devices to potentially damaging high voltage levels.

This functionality is vital for maintaining safe operating conditions and ensuring that monitoring and protective devices can operate effectively. The conversion from high voltage to a lower, standardized output enables engineers and technicians to analyze system performance, detect faults, and make informed decisions regarding electrical infrastructure.