百兆乏角型STATCOM的分相控制策略

Individual Phase Control Strategy for 100 Mvar-level Delta-connected Cascaded STATCOM

南网永富直流输电工程富宁换流站静止同步补偿器(STATCOM)工程采用3套角型35 kV/100 Mvar等级换流器,以提高弱交流电网下的电压稳定性,加快N-1故障后的直流恢复速度。为提高不对称故障下的电压支撑能力,STATCOM需具备分相控制功能。提出一种基于同步旋转d,q坐标系的电流分相控制策略,可有效实现对STATCOM输出电流的分相精确控制。结合工程应用,采用了电压外环的分相控制策略,可有效实现对500kV各相电压的分相调节。同时针对角型STATCOM的角内3次谐波环流问题,提出了相应的抑制策略。

Three sets of 35 kV/100 Mvar-level cascaded H-bridge static synchronous compensator（STATCOM） have been installed in Funing converter station of Yongfu HVDC project, which are used to improve the voltage stability of the weak AC network and accelerate the recovery of HVDC converter station of N-1 fault.To enhance the voltage ca- pacity under unbalanced condition,the individual phase control strategy of STATCOM is needed.A new individual phase current control strategy based on d, q rotary coordinate system is proposed, the inductor current can be accurately controlled individually.Simultaneously,an individual phase voltage outer loop control method is adopted in the project, based on which the 500 kV AC voltage can be regulated individually.A suppression strategy for the 3rd circulating current of the delta-connected cascaded STATCOM is described finally.