Commutation Failure Influence on Power Converse in UHVDC Power System

Abstract

For UHVDC transmission systems, the commutation failure of the DC system may cause the AC side power converse and may further lead to the AC line protection misoperation. This paper has analyzed power converse of AC system caused by commutation failure of DC system, and establishes the transmission line of UHVDC transmission line by using PSCAD/EMTDC simulation software. Using this simulation model to analyze how transition resistance in fault impact on power converse. The simulation results show: With the transition resistance increases, power converse presented a "V" shape change. By reducing positive sensitivity of sudden change relay or set a certain delay time (usually 40 ms) to start blocking mode pilot protection can prevent line protection misoperation caused by power converse.