Research On Partial Discharge Detection Of Switchgear Based On Ground Wave And Ultrasonic Signal Measurement

The switchgear is an important device in the distribution network.One of the reasons for the failure of the switchgear is partial discharge.Partial discharge can predict the deterioration of equipment insulation.If the partial discharge of the switchgear can be detected during operation,the insulation condition of the equipment can be grasped in time,which is beneficial to the maintenance of the switchgear and the safety of the power system.The detection technology and characteristics of TEV method and ultrasonic method make it suitable for the detection of partial discharge of high voltage switchgear.This paper has carried out in-depth research on the mechanism and detection methods of these two methods.The main research contents are as follows:in order to verify the effectiveness and practicability of the TEV method to detect the partial discharge of the switchgear,this paper simulates the surface TEV of the switchgear by the full-wave three-dimensional electromagnetic simulation software(XFDTD)based on the finite difference time domain method.The simulation results show that the switchgear The surface theoretically can measure the effective TEV signal,and the TEV signal has a certain correlation with the amplitude,pulse width,and detection distance of the excitation source.The TEV sensor is developed based on the simulation results and the detection principle of TEV.The overall design scheme of partial discharge fault pattern recognition using wavelet packet energy spectrum fractal feature method combined with radial basis function(RBF)neural network classifier is given.It has been proved that the classification efficiency of the scheme is better than 98%.The RBF network and BP network are used for pattern recognition based on the fractal characteristics of wavelet packet energy spectrum.The results show that RBF network is superior to BP network in recognition accuracy and algorithm efficiency.Based on the related research of TEV and ultrasonic,this paper designs a set of partial discharge detection system for switchgear,and develops a portable inspection device.It is verified by field test in a laboratory and a substation in Jiangsu.