Research On Detection Of Internal Insulation Defects Of Switchgear Based On Transient Earth Voltage Method

Switchgear is widely used in power system,it has become an important equipment of substation.With the development of national economy,the social power consumption has increased dramatically.For this reason,the power sector improves the efficiency of transmission lines by continuously increasing the voltage level,which requires higher and higher insulation level of switchgear,resulting in the increased probability of failure of internal insulation of switchgear.When the switch cabinet fails,due to the lack of effective live detection means,the staff can not find and carry out maintenance in time,which seriously affects the efficient operation of the power system to some extent.In this paper,the insulation defects of the switchgear are studied to effectively solve the problem of accurately finding the internal insulation defects of the switchgear.The transient to ground voltage method used in this paper is an advanced method to detect the fault of equipment.First of all,the theory of transient to ground voltage method is described.Aiming at the insulation defects caused by partial discharge in the switch cabinet,the detection of transient voltage is realized by placing external sensors on the surface of the equipment,so as to realize the detection of partial discharge and fault defects on the surface of the electrical equipment;and the defects can be located simultaneously.Secondly,this paper studies the basic theory of three-dimensional simulation of the internal structure of the switchgear,and simulates the electric field in the switchgear,the electric field in the bus room and the electric field in the cable room.Through the comparison and analysis of the above electric field simulation results,it can accurately judge the parts of components that may have partial discharge in power equipment.Thirdly,this paper simulated several typical fault defects,obtained the defect characteristics of different faults,and analyzed the location and detection of the fault points,providing the detection methods and judgment basis for the operators.At last,an example of the possible insulation fault of electrical equipment is analyzed by using the field test method,which shows the validity of the method.The detectionmethod can be well applied in engineering practice,accurately judge the defect points in the switch cabinet,improve the detection efficiency of the insulation defects of the switch cabinet,so as to ensure the safe and stable operation of the switch cabinet.