Research On Partial Discharge Characteristics Of Bubble Defects In GIS Basin Insulator

Gas Insulated Switchgear?GIS?is widely used in the power system.As the core device of the GIS,the basin insulator mainly undertakes the functions of insulation,support and isolation.However,the partial discharge induced insulation fault caused by the defects of the basin insulator occasionally occurs,which poses a potential threat to the safe operation of the GIS and the power grid.Therefore,A study on defect detection of basin insulator is of great significance to improve the reliability of GIS.This paper takes 252k V of single-phase basin insulator in GIS as the research object,and deeply studies the partial discharge characteristics of bubble defects from two methods of electric field simulation calculation and physical experiment.Firstly,according to the actual size of the basin insulator,a three-dimensional simulation model is established by using Solid Works drawing software.The electric field distribution rule of the defect-free basin insulator under the rated voltage is calculated by using ANSYS Workbench finite element analysis software.The influence of bubble defects at different positions and different volumes on the electric field distribution of the basin insulator is analyzed.According to the simulation of the electric field,the possible weak links in the process of insulator design and production are analyzed,and the methods of effectively eliminating the bubbles in the position of easy discharge to improve the product yield are studied by referring to the production process of the insulator.Secondly,using the actual basin insulator which is the same as the simulation model as the experimental object,the typical bubble defect is artificially set on it,and the experimental tooling is designed and the experimental platform is built in combination with the actual operating environment.Under the standard test voltage,the parallel circuit measurement method of pulse current method is used to detect the partial discharge signal of the tested basin insulator,and the damage degree of the partial discharge to the tested object is evaluated by the discharge capacity.Then,using the same experimental platform,the initial partial discharge voltage,the initial discharge quantity and the discharge signal waveforms of different volume bubble defect samples are measured;the influence of different volume bubble defects on the partial discharge characteristics of the basin insulator is analyzed,and the process of discharge development is investigated;the variation rule of bubble discharge under different field intensity is summarized;the corresponding ?-q_max maps,?-n maps and n-q maps are obtained by processing the raw data obtained from different experimental models,and the results are analyzed and compared to obtain the discharge rule of bubble defects with different volume inside the insulation.Finally,the electric field simulation and partial discharge experimental conclusion of the bubble defect of the basin insulator are summarized,and some suggestions are put forward for the production technology,repairable evaluation standard,engineering detection and fault diagnosis of the basin insulator.The thesis has 54 figures,6 tables and 83 references.