Detection of partial discharges in power capacitors using high frequency current transformers

A partial discharge detector has been developed which can detect partial discharges in power capacitors with adequate sensitivity by employing high-frequency current transformers (HFCTs). The principle of detection is described, and discharge measurements on capacitor units are reported. For large capacitance objects the inception and extinction levels are very clear and distinct in the HFCT technique. The technique can be extended to the in-site diagnostic testing of power capacitors