故障分量方向元件在交直流多端馈入系统中的适应性分析

故障分量方向元件在交直流多端馈入系统中存在适应性问题,目前缺乏相应的分析方法.文中分析了故障分量方向元件的原理,研究了对应的动作条件,理论推导了交直流多端馈入系统中馈线方向元件动作区间与换流器等值背侧阻抗波动区域的关系.结合换流器系统的故障响应特征,研究了不同故障场景下换流器等值序阻抗特性,推导了换流器序阻抗的波动范围.给出了故障分量方向元件在交直流混联系统中的适用条件,并分析了适用条件的影响因素.最后,PSCAD仿真验证了理论分析的正确性,为故障分量方向元件在非线性电网中的应用提供了理论基础.

Adaptability Analysis of Fault Component Directional Component in AC/DC Multi-terminal Infeed System

There is a problem of adaptability of fault component directional element in AC/DC multi-terminal infeed system, and there is no corresponding analysis method at present. In this paper, the principle of the fault component directional element is analyzed; the corresponding operation conditions are studied; and the relationship between the operation range of the feeder directional element and the equivalent back impedance fluctuation region of the converter in the AC/DC multi-terminal infeed system is theoretically derived. Combined with the fault response characteristics of the converter system, the equivalent sequence impedance characteristics of the converter in different fault scenarios are studied, and the fluctuation range of the sequence impedance of the converter is deduced. The applicable conditions of the fault component directional element in AC/DC hybrid system are given, and the influencing factors of applicable conditions are analyzed. Finally, the correctness of the theoretical analysis is verified by PSCAD simulation, which provides a theoretical basis for the application of the fault component directional element in nonlinear power grids.