Short-circuit current calculation on DC side of MMC-HVDC system with long distance transmission lines

The development of DC side faults in flexible DC transmission systems is rapid, and the short-circuit current rises very quickly. With the gradual expansion of flexible DC transmission technology to long-distance and long transmission line scenarios, the calculation of short-circuit current considering distributed parameter lines urgently needs attention. This article is based on the MMC DC side short-circuit current calculation universal model, studies the transmission line structure, establishes a long-distance transmission line mathematical model considering the distribution parameter characteristics and line frequency variation characteristics, and proposes a DC side short-circuit current calculation method for flexible DC transmission systems containing long-distance transmission lines. The comparison between simulation and calculation results verified the correctness of the theoretical model and the effectiveness of the calculation method.