【作者】 傅强；

【导师】 张兴敢；

【作者基本信息】 南京大学 ， 信号与信息处理， 2012， 硕士

【摘要】 输电线路发生故障时,会产生向线路两端传播的行波。本文深入分析了行波的产生原理,并给出波动方程。并由此得出行波反射和折射原理,并推导出反射和折射系数,为后面行波测量提供理论依据。详细分析了基于单端行波和双端行波分析法的故障定位原理。单端行波法具有准确度高的优点,但存在算法不成熟、自动测距可靠性较差的问题。双端行波具有自动测距可靠性高的优势,线路长度和时间同步系统存在误差,准确性比较低。提出小波变换在行波故障测距中的优势,并对小波基的选择进行了讨论。给出了小波变换的快速算法,便于行波故障测距的自动计算。介绍了基于小波变换的模极大值理论,找出信号在小波变换以后的模极大值,就可以检测出线路故障后行波到达的准确时间,并由此可以进行故障测距。行波信号的获取成为行波测距中的关键,分成两种类型：一种采用电流互感器获取电流信号；另一种采用专门设计的传感器获取电压行波信号。行波的波头的获取以及波速的确定,还有GPS时间同步装置,这些都是影响行波信号提取的因素,并给出解决办法。基于小波变换模极大值理论,设计了故障后行波测距模型,并在ATP Draw软件上进行仿真,并用Matlab进行计算。本文仿真了单端和双端行波测距模型,并用电压和电流行波进行分别计算,结果表明单端行波测距装置可以达到很高的精度。实际应用中,单端行波测距和双端行波测距装置的联合使用,会给行波故障定位带来更高的准确性和可靠性。更多还原

【Abstract】 When a fault happens on the transmission lines, it can produce the traveling wave spread to the ends of the lines. With deep analysis of the traveling wave principle, this article gives the wave equation. And thus, it obtains the principle of traveling wave reflection and refraction, and deduces the reflection and refraction coefficient, and provides a theoretical basis for the following traveling wave measurements. The fault location principle based on single-ended traveling wave and double-ended traveling wave were analyzed in detail. The single-ended traveling wave method has the advantages of high accuracy, but it has the problems about the algorithms immature and auto-ranging less reliable. Though the double-ended traveling wave has the advantage of high reliability of the automatic ranging, the accuracy is relatively low because of the line length and the time synchronization.This paper describes the advantage of wavelet transform on the traveling wave fault location, and the selection of wavelet base. The fast algorithm of wavelet transform was given to facilitate the automatic calculation of traveling wave fault location based on the wavelet transform modulus maxima value theory. It can find the exact time when the traveling waves arrive, thus it is able to be used for the fault location.How to obtain the traveling wave become the key of the traveling wave fault location. There are two types:one is using current transformer to obtain the current signal, the other is using a specially designed transformer to obtain the voltage signal. Getting the head of the traveling wave, the determination of the wave velocity, and the GPS time synchronization device are the factors affecting the traveling wave signal extraction, and based on which the solution can be obtained.Based on the wavelet transform modulus maxima theory, this article designs the ranging models of the fault traveling wave, and simulates with Matlab in ATPDraw software. The simulation of single-ended and double-ended traveling wave fault location model, and calculating the fault location using the voltage and current traveling wave, the results show that the single-ended traveling wave fault location devices can achieve high accuracy. Actually, single-ended traveling wave fault location and double-ended traveling wave distance measuring device used in combination, will give the traveling wave fault location higher accuracy and reliability.更多还原