Optimal Allocation Method of Dynamic Reactive Power Compensation to Suppress Simultaneous Commutation Failure of Multiple DC Lines

Abstract

After the AC side short-circuits fault occurs in the multi-infeed HVDC system, the voltage of the AC system keeps decreasing, which leads to the commutation failure of many or even all DC lines, which severely damages the security and stability of the power grid. In order to restrain DC commutation failure, a dynamic reactive power compensation device configuration method is proposed to restrain the risk of multiple DC commutation failures simultaneously. The type, installation location, and capacity of reactive power devices are optimized. Based on the duration of DC commutation failure and considering the interaction between DC and DC, the index of reducing the risk of commutation failure is proposed. According to the electrical distance, the weak area is determined, and then the optimal compensation location of dynamic reactive power is selected by the sensitivity index. A reactive power allocation optimization model is established to solve the optimal reactive power allocation scheme. The simulation results of a large power grid show that the optimal solution can effectively reduce the multi-DC commutation failures caused by AC faults while taking into account the economy.