大型光伏电站角形级联STATCOM电压控制策略

摘要

大型光伏电站并网后,给配电网乃至输电网的电压、电能质量等带来一系列的影响.静止同步补偿器(STATCOM)可稳定公共连接点电压并提高分布式电源的低电压穿越能力.提出了一种适用于大型光伏电站角形级联STATCOM的电压控制策略,能够支撑电网正序电压,减少公共连接点电压波动,并抑制公共连接点负序电压,改善电网电压不平衡;再结合角形级联STATCOM相电流与线电压的约束关系,给出了角形级联STATCOM相电流指令获取方法;最后,在PSCAD中搭建仿真模型验证了所提控制方法的正确性和有效性.%The grid-connection of large-scale photovoltaic power station may impact the voltage/power quality of distribution/transmission network while STATCOM can stabilize the PCC(Point of Common Coupling) voltage and enhance the low-voltage ride-through ability of distributed generation.A voltage control strategy for delta-connected cascaded STATCOM of large-scale photovoltaic power station is proposed to support the positive-sequence voltage of grid,reduce the voltage fluctuation of PCC,suppress the negative-sequence voltage of PCC,and restrain the voltage imbalance of grid.Based on the constraint relation between the phase-current and line-voltage of STATCOM,a method for obtaining the phase-current instruction of deltaconnected cascaded STATCOM is presented.The correctness and effectiveness of the proposed method are verified by PSCAD-based simulation.