行波相关法的输电线路故障定位

中文字数:2841,中文页数:12  英文字数:2312页数:10

 Introduction
 There existed three met hods for fault location : impedance method, fault analysis method and t raveling wavemet hod . The fir st two met hods have low precisions for influence of t hese cases : line parameter s ,fault point grounding impedance , operating mode of power system. The t raveling wave met hod has a higher precision , so it has been widely used now.There’re two met hods according to different t raveling waves data : single terminal location methodand two terminal location met hod . Two terminal t raveling waves location method is employed in this paper .
 The location p recision of t raveling wave method is influenced by wave velocity , line lengt h and the arriving time of wave f ront . How to accurately acquire t he arriving time of wave f ront is very important , and al so difficult . There are t hree
main algorit hms to achieve t his goal ; these are differential coefficient method , wavelet analysis met hod and correlation analysis met hod. It is easy to get the arriving time of wave f ront by t he moment when the differential coefficient of wave signal is beyond a given threshold , but t his algorit hm has a low p recision and may be influenced by noises . The classical wavelet analysis algorit hm has a higher precision in most cases . Modulus maxima principle is used to get t he mutation point in t his algorit hm . Now t his algorit hm is used widely , but t his met hod is so sensitive to the signal’s mutation point , it’s precision may be influenced.The correlation analysis algorithm is int roduced in t his paper to avoid above mentioned difficulty.The principle and t he met hod of how to use correlation analysis algorithm to locate t he fault in transmission line are int roduced. Some simulation modules are const ructed and some analysis results are given in t his paper .

引言
    精确故障定位的传输线是非常重要的电力系统。故障定位有三个方法：阻抗法、故障分析法和行波法。前两种方法因受一些情况例如参数、故障点接地阻抗、运行模式等影响而具有较低的精确度，而行波法具有较高的精确性。所以它现在已被广泛使用，根据不同的行波数据可分为两种：单端定位法和双终端定位法。本文主要介绍双终端定位法。
    行波法的精度位受波速、线路长度和前波到达的时间的影响，如何准确获取前波到达的时间非常重要也非常困难，有三种主要的算法可以实现这个目标；这些算法分别是差别系数法，小波分析法和相关分析法。人们利用时刻微分系数波信号超出某一标准值，很容易获取前波到达的时间，但是这种算法的精确度较低，可能受噪音的影响。经典小波分析法在大多数情况下具有较高的准确度，小波分析法中系数最大化原则用于获取突变点的位置。现在这种算法也被广泛使用，但这种方法对信号的突变点非常敏感，它的精确度可能会受影响。本文所介绍的相关分析法可以避免上述问题，本文介绍了如何使用相关分析算发找到输电线路故障的原则和方法，同时也介绍了一些仿真模块的构造和一些分析结果。

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