基于傅立叶算法实现的小接地电流系统单相接地故障选线研究

Faulty line selection for single-phase ground short circuits in non-direct earth neutral systems based on fourier algorithm

针对最大△(I sinφ)算法在计算过程中需要引入一个中间参考正弦信号,可靠性低且计算量较大的问题,引入了傅立叶算法实现最大△(I sinφ)小接地电流系统故障选线,采用该方法对中性点不接地系统进行分析,避免了多次求取电压和电流的相位过程,减少了投影和乘法运算次数,提高了运算速度,对于中性点经消弧线圈接地系统,在系统发生单相接地故障的暂态过程中,该方法同样有效。算例中设计了10 k V不接地系统,采用ATP-EMTP软件进行仿真,对故障在线路和母线上时进行故障线路选择。研究结果表明:该算法能更加可靠、快速地实现选线功能。

Aiming at the shortages of maximizing△（I sin φ） which required an intermediate referenced sine signal decreasing the algorithm＇s reliability and its computation process became more complicated, Fourier algorithm based-on maximizing△（I sin φ） principle was proposed in this paper, which was applied to neutral non-direct earth neutral systems as an example for analysis. This algorithm improved the reliability of problem solving and extremely simplifies the computation complexity of the original algorithm by avoiding computing phase angle between voltage and current. Based on the neutral non-grounded system as an example for analysis, it is effective in single-phase earth fault transient process in arc suppression coil grounded system. The simulation was conducted by ATP-EMTP in 10 k V neutral non-grounded system to choose the fault line when it was on lines and buses. The results prove that the algorithm is faster and more reliable to the faulty line selection.