Research On Anti-interference Technology In Partial Discharge Detection Of High Voltage Switchgear

High-voltage switchgear occupies an extremely important position in my country’s power distribution system,because the stability and security of power system will have a direct impact on people’s livelihood and economic development.Therefore,the study of anti-interference technology in PD detection of high voltage switchgear is of great significance to the technical stability and security of distribution network.In the research and discussion of this article,the focus is on the partial discharge detection technology and anti-interference technology at home and abroad.At the same time,a comprehensive analysis and demonstration of the basic characteristics of the switchgear partial discharge and external electromagnetic wave interference during the work are carried out.Firstly,based on the finite element analysis software COMSOL,the partial discharge characteristics and the pulse characteristics in the external interference signal of the switchgear are studied and analyzed comprehensively.The results show that the basic characteristics of the external interference signal are similar to that of the partial discharge signal,but it can still be distinguished by relevant technical means.Secondly,the experiments of internal discharge and external interference pulse of HV switchgear under two kinds of typical defect models are simulated in the laboratory,and the time-frequency characteristics of these two models are analyzed,then the internal discharge and the external interference pulse signal can be separated.Through the experiments,it is found that the internal discharge electromagnetic wave has occurred many times of refraction in the metal cabinet of the switchgear,and then the oscillation at the characteristic spectral point occurs,however,there is no obvious oscillation point of the external discharge electromagnetic wave in the spectrum of the detecting system.Therefore,these two kinds of pulse signal characteristics can be recognized and distinguished according to the method of equivalent time and equivalent frequency.Then,according to the high-voltage switchgear when partial discharge occurs,the discharge signal oscillates seriously at a certain frequency,but the external interference signal does not appear this kind of phenomenon,based on the technology of transient ground voltage（Tev）and electromagnetic wave receiver,an anti-interference partial discharge（PD）detection system is developed.Finally,according to the actual experimental demonstration,the effective recognition and distinction of partial discharge and external interference signals in the sensing equipment are realized,this method makes use of the principle of equivalent time and equivalent frequency to achieve the related recognition and division effect,thus,the detection accuracy of partial discharge in high voltage switchgear and the anti-interference performance of the equipment are further improved.