海上风电经VSC-HVDC系统受端电网不对称 故障抑制策略

The failure of the receiving-end grid in the voltage source converter (VSC) based high voltage direct current (HVDC) system of offshore wind power not only affects the operation status of the AC/DC side system of the receiving-end converter station, but also hinders the normal operation of the sending-end converter station and offshore wind turbines in severe cases. In order to solve this problem, the propagation mechanism of asymmetric faults in the receiving-eng grid of offshore wind power transmission system through VSC-HVDC was analyzed, and a negative sequence component suppression strategy based on Lyapunov function method was proposed. Firstly, the topology structure of the offshore wind turbine transmission system through VSC-HVDC was established, and the propagation mechanism of asymmetric faults in the receiving-end grid was analyzed. Secondly, based on the mathematical model of the receiving-end converter station, a negative sequence switching function that satisfies the global stability of the Lyapunov function is derived, and the coefficients of the switching function are solred. Thus, the corresponding Lyapunov function controller is further designed. Finally, the proposed strategy was compared with traditional PI control based on MATLAB/Simulink software simulation to verify its correctness and effectiveness.