在电力系统中，配电网是直接与用户连接的环节，承担着电能在传输终端分配的职责，一旦发生故障，将会对用户造成停电事故，影响人们的工作生活。对于中性点非有效接地的配电系统，发生单相接地故障后系统的接地电流很小，导致利用工频量进行故障测距很困难。针对这一问题，本文采用行波法进行故障测距，因为行波法具有精度高，不受系统运行方式影响，适用范围广等一系列优点。因此，本课题针对配电线路故障行波测距的研究有着重要的意义。 故障发生后，故障点沿着线路将产生由近而远传播的暂态行波信号，以分布参数线路模型为基础，运用数学理论推导故障行波中存在的行波特征参数。利用相模变换对故障信号仿真分析，分离出暂态电压、电流行波α模量，得出暂态电流行波α模量具有明显的信号特征的结论。 本文利用形态梯度算法提取暂态电流行波α模量的波头，其中重点分析了影响波头准确性的几种结构元素。通过仿真实验，指出了形态学梯度算法存在无法识别波头极性的缺点。 针对形态梯度算法在判断行波极性和滤波方面的不足，本文将形态滤波和导数法相结合，提出了一种形态学-导数的故障测距方法。先构造形态滤波器对行波α模量滤波，再利用改进导数法提取滤波后α模量的波头，进而通过单端测距原理实现准确故障测距。 本文采用Matlab/Simulink构建辐射状配电线路模型，详细分析了影响配电线路行波故障测距精度的主要因素。仿真结果表明：形态学-导数法原理简单，计算量小。与形态学梯度算法比较，测距精度更准确，具有较高的可靠性和有效性。

Distribution network is a segment that is directly connected with the users in the power system. It bears the responsibility that the power is allocated in transmission terminal. In the event of line fault of the distribution network, line fault will cause the blackout accident for users and affect people's work life. When distribution system with non-effectively grounded neutral occur ground fault, the fault current is very small in amplitude, which leads to the trouble of measuring fault location of using the power frequency. To solve this problem, the travelling wave method is used to measure fault location because of a series of advantages of the travelling wave method with high precision, unaffected by system operation, wide application and so on in this paper. Therefore, this topic has important significance for the research of fault location of the travelling wave of the distribution line. After the fault of the line, the fault point will produce the signal of the transient travelling wave spreading from near and far along the line. Based on the line model of distributed parameter, this paper uses the mathematical theory to derive the characteristic parameters of the fault travelling wave. Use Sagami transform to simulate the fault signals, and to isolate the α-mode of the transient voltage travelling wave and the transient current travelling wave, and to obtain the conclusion that the α-mode of the transient current travelling wave has obvious signal characteristics. The morphological gradient algorithm is used to extract the wave head of the α-mode of the travelling wave in this paper. Some structural elements which affect the accuracy of wave head are analyzed mainly. Simulation results indicated that the algorithm of the morphological gradient exist the shortcomings of unrecognizing the polarity of the head-wave. According to the disadvantage of morphological gradient in judging the polarity of the travelling wave and filtering, this paper combines morphological filtering and derivative method, and proposes a fault location algorithm integrating morphology with derivation., this algorithm first constructs the morphological filter to filter the α-mode, and then uses the derivative method to extract the wave head of the α-mode, and finally achieves accurate fault location through the single-ended fault location principle. This paper uses Matlab/Simulink to construct the radial distribution line mode, and detailed analyses the main factors that influence the accuracy of the travelling wave fault location of the distribution line. Simulation results show that the principle of the algorithm of the morphological derivative is simple and its calculation burden is light. Compared with the morphological gradient algorithm, the accuracy of fault location is relatively exact. This algorithm is provided with a higher reliability and validity.