基于数学形态学的故障暂态信号研究

发布时间：2019-05-17 21:05

【摘要】：随着电网规模的不断扩大以及高压输电线路的逐步增加,电力系统对继电保护提出了更高的要求。根据电力系统统的暂态稳定性要求,必须实现保护的可靠、快速动作。基于工频量的继电保护其动作速度已经无法满足要求,而采用故障的暂态分量可以构成超高速保护,它具有很好的速动性,因此它可以满足超高压输电线路的速动要求。受限于信号分析手段的不足,很难将暂态初始行波信号与各种噪声干扰相分离,使保护的发展受到限制。输电线路发生故障时,线路上会产生由故障点向两端母线传播的暂态行波信号,而输电线路的故障特征就包含在这些信号中。本文在仔细分析输电线路行波产生及其传输过程的基础上,将数学形态学的理论应用于暂态行波故障特征的检测研究中。提出一种基于数学形态学的行波方向保护方案。利用数学形态学的多分辨算法对故障信号进行滤波处理并提取暂态初始行波信号的局部特性,得到行波信号的瞬时功率局部模极大值,就可以准确地判断出故障时突变点的极性特点,从而实现方向保护。本文利用Matlab/simulink软件对500kV的双端供电的超高压输电线路进行数值仿真分析,对该保护方案的可靠性和有效性进行仿真验证。仿真分析表明该保护方案不受故障类型,过渡电阻,故障时刻等因素的影响,能够可靠地排除噪声干扰,准确地判断出故障方向。
[Abstract]:With the continuous expansion of power grid scale and the gradual increase of high voltage transmission lines, the power system puts forward higher requirements for relay protection. According to the transient stability requirements of power system, the reliable and fast operation of protection must be realized. The operation speed of relay protection based on power frequency has been unable to meet the requirements, and the transient component of fault can be used to form ultra-high speed protection, which has good rapidity, so it can meet the requirements of ultra-high voltage transmission line. Limited by the shortage of signal analysis methods, it is difficult to separate the transient initial traveling wave signal from all kinds of noise interference, which limits the development of protection. When the transmission line fails, the transient traveling wave signal propagated from the fault point to the bus at both ends will be generated on the line, and the fault characteristics of the transmission line will be included in these signals. In this paper, based on the careful analysis of the generation and transmission process of traveling waves on transmission lines, the theory of mathematical morphology is applied to the detection of transient traveling wave fault characteristics. A traveling wave direction protection scheme based on mathematical morphology is proposed. The multi-resolution algorithm of mathematical morphology is used to filter the fault signal and extract the local characteristics of the transient initial traveling wave signal, and the instantaneous power local mode Maxima of the traveling wave signal is obtained. The polarity characteristics of the sudden change point in the fault can be accurately judged, and the direction protection can be realized. In this paper, the Matlab/simulink software is used to simulate and analyze the EHV transmission line supplied by 500kV, and the reliability and effectiveness of the protection scheme are verified by simulation. The simulation analysis shows that the protection scheme is not affected by fault type, transition resistance, fault time and so on. It can reliably eliminate noise interference and accurately judge the fault direction.
【学位授予单位】：河南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM75

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