Partial discharge detection in Transformer, Switchgear, Cables, GIS provides an indication of localized points of degradation in theinsulation system. Detecting these weak points is of interestfor condition based maintenance, asset replacement programs and improving overall network reliability. With on-line PD detection, tests can be done under normalworking conditions with equipment in-service. Continuousmonitoring can also be achieved in which measurements aremade over an extended period.