基于VSC-HVDC的DFIG风电场低电压穿越改进控制策略

An improved control strategy of DFIG wind farm low voltage ride through based on VSC-HVDC

提出了一种适用于VSC-HVDC系统并网DFIG风电场的低电压穿越控制策略。根据DFIG机组和VSC模型,计算了无功功率极限。传统的Crowbar电路在系统故障时将转子侧换流器(RSC)进行短路,使DFIG风电场失去对系统提供无功功率的能力。提出了改进控制策略,根据电网故障严重程度控制Crowbar电路的动作。根据风电场和VSC-HVDC系统各个换流器的功率极限,提出了输电系统风电场侧换流器(WFVSC)优先的无功功率分配策略,根据电网的无功缺额分配换流器之间的无功出力。使用MATLAB/Simulink平台搭建了仿真系统,对改进控制策略进行了验证。

A control strategy for DFIG wind farm low voltage ride through based on VSC - HVDC is proposed in this pa-per. In accordance with the model of DFIG and YSC , the limitation of reactive power is calculated. When the system breaks down, the traditional Crowbar circuit will make a short circuit in RSC which makes DIFG unable to provide reactive power to the system. An improved control strategy is proposed so that the Crowbar circuit will act according to the level of the fault. In consideration of the power limitation of each convertor station of wind farm and VSC- HVDC , the strategy of reactive power allocation is put up which will allot the reactive power output according to the reactive power gaps of the system. A simulation model is established using MATLAB/Simulink to verify the improved control strategy.