insulation strength frequencies important inservice maintenance distribution ensuring vital components addressed leading efficient operation reliability safety transformer core detect mechanical switching surges proper connection detect abnormalities broadly classified preventing failures design specifications testing verifies transformer testing electrical acoustic electrical shocks full load energy losses induced voltage tests verify withstand capability optimizing performance types electrical power systems involves applying load eddy current losses maintaining grid stability nonsinusoidal waveforms fra measures partial discharges safe operating limits applying reduced voltage applying rated voltage correct turns ratio