Comparison and analysis of the fault arc characteristics of flexible DC transmission lines

摘要

VSC-HVDC grid is one of the important development directions of the smart grid in the future. The arc characteristics of transient fault on the transmission line are the theoretical basis for determining reclosing time and reclosing strategy of DC circuit breaker. In this study, the process of the transient single-pole ground fault on the true bipolar VSC-HVDC transmission line is analysed and the arc model of the fault is determined according to the fault characteristics. Then a two-terminal voltage source converter-high voltage direct current (VSC-HVDC) system including this arc model is built in power systems computer aided design (PSCAD). The primary and secondary arc characteristics of the transient single-pole ground fault on the transmission lines are simulated and compared with the arc in AC system. It is shown that the arc extinction time of the flexible DC transmission system is lesser than that of the AC system at the same voltage level.