Sensitivity Based Optimized Voltage Control Strategy for Power Grid with UHVDC Feed in

For power grid with ultra-high voltage direct current (UHVDC) feed in and AC interties to neighbor areas, once the HVDC is blocked, the power flow of the grid would experience sharp variation and the AC interties power might increase heavily to compensate the shortage caused by HVDC block. In this case, the grid voltage control is of great significance to maintain the system stability. In this paper, an optimized voltage control method is proposed. The sensitivity of bus voltage to reactive power injection is used to estimate voltage control effects, and the minimum weight summation of voltage deviation to reference of the key buses is selected as the objective. Considering certain constrains, the optimized reactive power control strategy could be obtained. The strategy combines multiple control measures and apply various reactive power resources for coordinated control at the same time. It could be implemented either as preventive control before the fault or as emergency control after the fault occurs, or as post fault recovery control. Cases study demonstrate the effectiveness of the proposed control method.