双馈风电场联络线单相接地故障单端测距分析

Analysis of single-terminal fault location in DFIG wind farm tie-line

针对单相接地故障,风电场联络线故障特性受风电场运行方式、低电压穿越策略等因素影响较大,传统故障测距方法已不能很好地适用于风电场联络线故障测距。为此,本文基于传统单相接地短路解复数方程故障测距方法,研究了双馈风电场序阻抗特性,建模分析了双馈风电场联络线短路电流、电压特性。基于零序网络,指出了该方法在风电场联络线故障测距中产生误差的关键因素,并仿真研究了风电场不同风速和投运机组数对这种因素产生的影响,最后经过迭代补偿故障支路零序电流相位有效提高了测距精度。

The single phase to ground fault characteristics of wind farm tie line are affected strongly by wind farm operation mode,low voltage ride through（ LVRT） strategy,and so on,so that traditional fault location methods cannot be applied to the wind farm tie line. According to a traditional fault location method of solving complex equation,impedance characteristics of doubly fed wind farm tie line was studied. Based on PSCAD/EMTDC,a simulation mode of doubly fed wind farm tie line were established,and its short circuit current and voltage characteristics were analyzed through simulation. Based on the zero sequence network of the doubly fed wind farm tie line,the key factor of introducing error when adopting the proposed method was indicated,the influences on the factor under different wind speed and different number of operating wind turbines were studied through simulation,and the accuracy of fault location was effectively improved by iterative compensating zero sequence current of the fault branch.