模极大值均方根比在配网暂态接地故障选线中的应用研究

针对小电流接地系统单相接地故障暂态量电流特征,给出一种以零模电流模极大值均方根比值为判据的接地故障暂态选线方法。利用小波包分析和奇异性检测理论对故障线路与非故障线路零模暂态电流奇异性差异进行分析,计算选线频带内各线路零模电流的模极大值序列及模极大值的均方根值,并根据均方根比值确定故障线路。理论分析和EMTP大量仿真试验结果表明,该方法能适应工程应用中可能存在的影响因素,具有灵敏度高、自适应能力强、选线准确等特点。

Application research for the root mean square ratio of modulus maxima in the distribution network transient fault line selection

Aiming at the transient zero-mode characteristics of single-phase ground fault in neutral point ineffectively grounding system, a method of fault line selection is presented based on the Root Mean Square (RMS) ratio of modulus maximum. This method analyzes the singularity differences of transient current between fault line and non-fault line by using wavelet packet theory and singularity detection theory. It calculates the modulus maximum RMS in line selection band and determines the fault line by calculating the ratio of modulus maximum RMS. Some factors that might influence the effect of fault line selection in the actual application are taken into account. Results and a lot of EMTP simulation show that the proposed method is of high sensitivity and accuracy and strong adaptive ability.