Research on Emergency Power Support Strategy for Multi-HVDC Transmission Network Based on Power Trajectory Sensitivity

Abstract

In order to reduce the power surplus of the sending-end power grid and improve its transient power angle stability, emergency DC power support (EDCPS) can be provided to the sending-end power grid after the AC tie line fails in the multi-DC transmission power grid. Based on the EDCPS strategy, the power distribution among the DC lines depends on the close coordination between the DC lines. Therefore, it is necessary to design a coordinated control center with a higher control level, which brings considerable difficulty to the protection and control of the DC system. Accordingly, this paper proposes a coordinated control strategy for emergency DC power support based on the sensitivity of the weak link generator power trajectory. The DC lines are sorted based on the sensitivity of the electromagnetic power of the unit to the boost power of the DC lines. After the failure, give priority to the most sensitive DC line to participate in support. This strategy can minimize the number of DC lines participating in EDCPS, reduce the difficulty of coordinated control, and provide better support effects. In the modified IEEE 10-machine 39-node system, the effectiveness of this method is proved.