风电场集电线路单相接地故障组合测距

Combined fault location for single-phase grounding of wind farm collection line

针对风电场集电线路由于短路故障引发的弃风窝电难题,提出采用矩阵法和阻抗法相结合的风电场集电线路组合测距方法。首先,通过全相位快速傅里叶变换相位差校正法分别获取电压、电流的基波幅值和相位;然后,建立风电场内区段与测点间的网络描述矩阵,并根据风电场内普遍采用接地变压器的特点,以故障期间的零序电流为基础,构建故障区段定位的改进矩阵判据,快速有效的确定故障区段;最后,由于风电场集电线路多为电缆敷设,应用考虑分布电容的单端阻抗测距方法,进行单相接地短路故障点查找,准确获得故障点的位置。PSCAD/EMTDC实验结果表明,新方法能够在定位故障区段的基础上,准确实现故障测距,具有良好的有效性,并可在一定程度上满足风电场对测距精度水平的要求。

The short-circuit fault in wind farm collection lines may result in the wind curtailment and poor power transmission ability.To address this issue,a comprehensive fault location method based on the combination of matrix algorithm and impedance approach is proposed.Firstly,the fundamental amplitude and phase of voltage and current are obtained respectively by the all-phase fast Fourier transform phase difference correction method.Then,the network description matrix between the section and the point in the wind farm is established.According to the characteristics of grounding transformer commonly used in the wind farm,an improved matrix criterion based on the zero sequence current during fault is formulated to determine the fault section quickly and effectively.Finally,due to the wind farm collection lines are mostly cable laying,the single-terminal impedance location method considering distributed capacitance is applied to find single-phase grounding fault points and obtain their precise locations.PSCAD/EMTDC experimental results show that the proposed method can accurately achieve fault location on the basis of locating fault segments.It has good validity and can meet the requirement of the wind farm for ranging accuracy to a certain degree.