Simulation Analysis on Overvoltage Inside High-End Valve Hall of ±800 kV UHVDC Project

In view of complicated air gaps and multiple electrodes inside the valve hall of converter station for ±800 kV UHVDC project,where multi important equipment are installed,the design of the valve hall is one of the important key points of ±800 kV UHVDC project,so it is of significance for the reasonable design of the valve hall to research the distribution and numerical value of overvoltage inside the valve hall.Based on simulation calculation of ±800 kV UHVDC power transmission system from Xiangjiaba to Shanghai,the simulation research on switching overvoltages under various fault conditions occurred in ±800 kV UHVDC transmission system is performed and summarized.Combining with the arrester layout as well as the air gap distribution,actual positions of voltage key points and their influencing spheres inside the high-end valve hall of Fulong converter station at the sending end of the UHVDC transmission system,the distribution of overvoltages inside the valve hall and their values at the most serious time are obtained.Simulation results show that overvoltages inside the valve hall do not appear at the same time,but concentratedly appear when some kinds of serious faults occur.