基于频域参数识别的距离保护算法

Distance Protection Algorithm Based on Parameter Identification in Frequency Domain

针对输电线路最常发生的单相接地故障,以最小二乘矩阵束算法为基础,提出了一种在线路末端故障时计算距离准确、在线路末端附近故障时计算距离具有正误差现象的频域距离保护算法。该保护算法的核心是假设故障点之后的零序回路为纯电感线路,列写出在频域具有3个未知变量的线性测距方程。电磁暂态仿真程序的仿真试验表明,在集中参数模型的短距离输电线路上,该保护算法在线路末端故障时测距准确,在线路末端附近经过渡电阻接地故障时不存在超越问题。

Based on least square matrix pencil algorithm,a novel distance protection algorithm in frequency domain for single-phase-to-earth fault of transmission line is proposed,which can accurately calculate the fault distance when faults happen at the remote terminal,and get a positive fault distance error when faults happen around the remote terminal.Assuming that the impedance of zero phase sequence loop after the fault point is pure inductive,a linear distance measure equation with three unknown coefficients is deduced.Simulation results with electromagnetic transient program（EMTP） show that for concentrate parameter model of short-distance transmission lines,this algorithm can measure distance accurately when faults happen at the remote terminal.It can effectively prevent the overreach phenomenon when faults happen around the remote terminal through transient resistance.