Space Charge Simulation for Basin Insulator of High Voltage DC GIL Considering Temperature Gradient

Under DC voltage and temperature gradient, space charge is easy to accumulate inside the basin-type insulator of DC gas-insulated transmission line (GIL), leading to local electric field distortion. Therefore, it is of great significance to study the space charge accumulation characteristics of basin-type insulators under DC voltage to improve the insulation performance of DC GIL. DC GIL basin insulator is taken as the research object, and a multi-physical field coupling model of electric-heat-fluid-charge based on two-dimensional bipolar carrier model is established to study the space charge characteristics and electric field distribution of basin insulators under different temperatures, voltage levels and voltage polarities. The results show that the model can effectively simulate the distribution of space charge and electric field in basin insulator. Under the working condition of the basin insulator, the space charge mainly accumulates at the interface between the metal and the insulating material, and the maximum space charge density is 156.59 mC/m³, which causes the internal electric field distortion to a certain extent. The space charge simulation of insulators under complex working condition can solve the current situation that it is difficult to measure space charge directly in power equipment. Besides, the simulation method and results can provide theoretical support for insulation optimization design of DC GIL.