适用于双馈风电场联络线故障选相方法

Fault Phase Selection Method for Interconnection Line of DFIG-based Wind Farm

双馈风电机组复杂的故障电流特性使得应用于双馈风电场联络线上的传统选相元件性能严重劣化,难以满足双馈风电场联络线保护与重合闸的选相需求。根据双馈风电机组的低电压穿越控制策略,分析了传统选相元件应用于双馈风电场联络线面临的缺陷。提出了基于相间电压突变量和相电压突变量幅值比较的故障选相新方法。根据双馈风电场侧保护安装处相电压突变量与相间电压突变量之间的比例关系,构建了故障相别选择系数,并利用故障相别选择系数在不同电网故障类型下的特征,以实现故障选相。仿真结果表明,所提选相元件可以可靠地选出故障相。

The complicated fault current characteristics of doubly-fed induction generator（DFIG）deteriorate the performance of the conventional superimposed phase selectors when they are applied on the interconnection line of DFIG-based wind farm,which is difficult to satisfy the requirement of phase selection of interconnection line protection of DFIG-based wind farm and reclosing.Based on it,the defects of the traditional phase selectors applied on the interconnection line of DFIG-based wind farm are analyzed according to the low voltage ride through control strategy of DFIG.Then,a new fault phase selector is proposed based on the comparison of superimposed amplitude between phase voltage and line voltage.The selection coefficient of fault phase is established based on the proportional relation of superimposed amplitude between phase voltage and line voltage at the relay location of DFIG-based wind farm.According to the characteristics of the fault phase selection coefficient under different fault conditions,the fault phase selection can be realized.A variety of simulation cases show that the performance of the proposed fault phase selection method is much better than that of conventional method which can select the fault phase effectively.