选相及方向元件在风电接入系统中的适应性分析

Adaptability Analysis of Phase Selectors and Directional Relays in Power Systems Integrated with Wind Farms

对传统选相及方向元件在风电接入系统中的适应性进行了研究分析。传统选相和方向元件均基于故障序分量网络分析,故障期间风电系统正负序阻抗相差较大且幅值远大于常规电网的特点使得风电侧正负序电流分支系数具有较大偏差,从而造成了基于正负序电流分支系数近似相等的传统选相和方向元件并不适用于风电接入系统。PSCAD建模仿真和现场故障录波数据验证了适应性分析结论。最后基于适应性分析结论给出了风电接入系统的选相和方向元件建议。

The adaptability of traditional phase selectors and directional relays in power systems integrated with wind farms is studied. Additional fault network is the basis for both traditional phase selectors and directional relays. The positive and negative sequence impedances of the wind power system vary widely and their amplitudes are both much larger than that of a regular power system during a fault. The impedance characteristics will then lead to a big difference between positive and negative current branched coefficients at the wind power side. Thus traditional phase selectors and directional relays based on equal positive and negative current branched coefficients are not necessarily suitable for wind power integration. Data from PSCAD simulation and field fault record have verified the theoretical analysis of adaptability. Eventually, research recommendations for phase selectors and directional relays suitable for power systems integrated with wind farms are given according to the adaptability analysis.