中性点经小电阻接地风电场集电线路单相接地故障测距研究

风电场集电线路呈现多分支、多电源接入的形态。线路发生单相接地故障后,不同分支上风机依据感受到的电压降的不同而自动投入不同的低穿控制策略,从而会导致输出不同的分支电流,使得基于阻抗原理的测距方法失效。该文巧妙地利用风机箱变高压侧采用三角形接线的现实,无零序电流回路,提出基于故障区段逐次搜索的单相接地故障测距方法,并引入描述故障点弧光接地的对数电弧模型,实现了较高的测距精度。仿真算例和实际案例数据验证了算法的有效性。该算法可同时求解得到故障点电弧的长度,为后续的故障类型辨识奠定了基础。

Single-line-to-ground Fault Location in Wind Farm Collection Line With Neutral Point Grounding With Resistor

The power collection line in wind farm presents the operation form of multi-branch and multi-power supply access. After a single-phase grounding fault occurs on the line, the wind generators on different branches will automatically input different control strategies according to the different voltage drop they feel, which will result in different branch current output. So the traditional method based on impedance principle was invalid. This paper cleverly used the fact that the high voltage side of the step-up transformer in branch adopts triangle connection, without zero sequence current through, and put forward a novel fault location method based on the successive search of fault section. And the logarithm arc model was introduced to describe arc grounding of fault point, which achieves high ranging accuracy. The effectiveness of the algorithm is verified by simulation and actual recorded data. Arc length can also be calculated out in algorithm, which lays a foundation for the subsequent fault type identification.