Deterioration diagnosis by detection of partial discharge in a cable joint of 22 kV network

Recently, power failure caused by partial discharge (PD) occurred at the cable joint of 22 kV network in a substation, because insulation deterioration diagnosis technology in electric power systems is not enough established yet. A prediction of dielectric breakdown by detection of PD is one of the important problems to establish insulation deterioration diagnosis in electric power systems. Therefore we carried out experiments for the purpose of detection of PD in ethylene-propylene rubber (EPR) used as an insulation material in electric power systems. The EPR used in this experiment is the same material for insulation of actual cable splicing of the 22 kV network. We measured the propagation characteristics of acoustic wave in the EPR by using acoustic emission (AE) sensor in this experiment. Next, we simulated a PD in the EPR and analyzed V-I characteristics and φ-q-n characteristics.