Research On Stress And Electric Field Simulation And Detection Method Of Internal Defect Of GIS Basin Insulator

For the characteristics of small dimensions,resisting external environmental interference,the long maintenance period,as well as the convenient installation and delivery,the Gas Insulated Switchgear(GIS)is increasingly applied in the modern electrical system,especially in the urban center where the land resource is stretched.However,with the growing amount of the GIS,the involved electrical faults increase apparently and are taking more and more attentions from power sectors.Among all kinds of electrical faults,the insulation failure accounts for a large proportion,the reasons causing insulation failure are complex and diverse,the factors like unreasonable designs,resides from the manufacturing process,installation errors or the scratches resulting from installation,and the external damage in the operating process may lead to distortion of the internal electrical field,deterioration of the insulation property,and even cause equipment failure finally.As the critical element of GIS,the quality of the basin-type insulator determines the overall quality of GIS,and many kinds of GIS faults are caused by faults of the basin-type insulator at the moment.Consequently,the research on the detection and analysis of defects contributes to the safe and reliable operation of GIS.In this paper,the research object is the basin-type insulator of GIS at the rated252 kV,the stress and electric field distributions of the insulator are calculated by the finite element method,which is difficult to complete by the conventional method.The simulation calculates the stress and electric field distributions for the flawless basin-type insulator and the basin-type insulators with air gap defects of different configurations and sizes.The comparative analysis between them provides some theoretical references for the defect detection of the insulator with internal air gaps.The experimental models of insulators with internal bubbles or crack defects are established to carry out the experiment research about ultra high frequency method for the detection of partial discharge based on the varying pattern of electric field in the insulator.The corresponding column diagrams N-?,q-?and qN-are obtained through dealing with data taken from different experimental models,and the discharging pattern of insulators with different internal air gap by comparing and analyzing the results,Which provides some references for the online detection ofinsulators with internal defects.