Partial Discharge Detection Method of Electrical Equipment Based on UHF Method

Abstract

Partial discharge is an early symptom of insulation defects. In the field application, the detection method can not accurately identify those noise signals mixed in the partial discharge signal, which limits the detection to a certain extent. Based on UHF method, a partial discharge detection method for electrical equipment is designed. When partial discharge occurs, the exchange between charges, the radiation of electromagnetic waves and the consumption of energy will occur at the discharge position, causing the change of electrode potential. For the phase distribution spectrum, the signal characteristics produced by partial discharge are extracted from three aspects: statistical information, time domain information and frequency domain information. During detection, UHF sensor is placed on the basin insulator, and then UHF signal is received. Insulation defects are identified according to various differential discharge patterns formed by the discharge characteristics of different defects. Test results show that the signal spectrum detected by UHF partial discharge roughly matches the typical discharge spectrum, and it is determined that there is partial discharge in this area. This method has high positioning accuracy and meets the detection requirements of electrical equipment.