VSC-MTDC联网风电场的交流故障穿越控制

研究了用于风电场并网的柔性多端直流输电系统(VSC-MTDC)交流故障穿越协调控制策略。考虑到实际风电机组的故障保护阈值,提出将升频法/降压法和直流卸荷电路相结合的故障穿越协调控制策略,同时故障期间受端站控制方式由有功电流控制优先切换到无功电流控制优先,根据电网电压跌落深度,按一定比例向电网提供无功功率,以帮助电网电压故障后迅速恢复。基于MATLAB/Simulink搭建了风电场经三端柔性直流输电并网系统模型,验证了所提控制策略的有效性。

A Control Strategy for AC Fault Ride-through of Wind Farm Integration Through VSC-MTDC

A control strategy for AC fault ride-through of wind farm integration through VSC-MTDC is discussed in this paper. Considering the fault protection threshold of actual wind turbines, this paper presents a coordinated control strategy of fault ride-through which combines voltage drop/frequency increase method with DC unloading circuit. Furthermore, in the duration of the fault, the control method at the receiving end is switched from preference of active current control to preference of reactive current control. Depending on the grid voltage sag, reactive power is supplied to the grid at a certain proportion so as to help the grid voltage recover quickly after the fault is over. A model of wind farm integration through three-terminal VSC-MTDC is established via MATLAB/Simulink, and the effectiveness of the proposed control strategy is verified.