DC Voltage Cooperative Control Method for VSC-HVDC Under Receiving-End Grid Fault

Receiving-end grid fault may induce DC overvoltage in the high voltage direct current-based voltage source converter (VSC-HVDC). The existing DC voltage control method has a fixed initiation threshold, and the active power regulation of the sending-end converter (SEC) and receiving-end converter (REC) are independent, which is prone to non-essential activation of active power regulation of SEC and the energy-dissipating device(EDD). By quantifying the DC voltage control capability of REC under AC current and reactive power constraints, the concept of maximum permissible duration (MPD) to avoid DC overvoltage when regulating REC alone and its calculation method are proposed. By introducing the power rebalancing duration, the operating range of converters that ensures DC voltage safety, namely the DC voltage safety domain (DVSD), is portrayed. Considering the MPD and the frequency limitation of sending-end grid, the calculation methods of control sequence and reference values of SEC and REC are proposed. In conjunction with DVSD, the DC voltage control method is proposed based on active power linear reduction of SEC and cooperation with REC. Simulations show that the proposed method can prevent excessive active power regulation of SEC and avoid EDD to the maximum extent while avoiding DC overvoltage.