New PD measurement method for high power transformer PDM in service operation

Partial discharge measurement is a kind of effective condition check method for high power transformer. Normally, when a high power transformer needs to be checked by partial discharge measurement periodically, outage is required. Here, a newly developed measurement method for transformer is introduced in which a new kind of capacitive coupling sensor is applied. The sensor consists of a pair of metal plates and a high frequency CT, which can be installed at the flange of the high voltage bushing of the transformer during the transformer in commercial service operation, without any outage.