Simulation of HVDC wall bushing performance under unevenly wetted conditions

The electric field distributions for HVDC wall bushings with different dry zone lengths are discussed and their critical flashover voltages predicted using an E-field based model. The simulation yields results in good agreement with experimental results. It is shown that some important aspects of wall bushing flashover, such as the U-shaped characteristics of critical flashover voltage versus dry zone length, critical dry zone length, are well reproduced by the simulation.