A Potential Transformer (PT) plays a key role in Electrically Isolating the instrument and relays from the high voltage side and for Transferring voltage from higher values to proportional lower values upto 63.5V, 100V, 110V or as per standard equipement. The Class of accuracy of metering PT are 0.1, 0.2, 0.5, 1.0 and protection is 3P.