基于多频带分量重构的小电流接地系统自适应选线新方法  

A New Adaptive Faulty Line Detection Approach Based on Reconstruction of Multi-band Components for Small Current Neutral Grounding System

作　　者：张仲孝[1] 苗世洪[1] 林湘宁[1] 刘沛[1] 

机构地区：[1]华中科技大学电气与电子工程学院,湖北省武汉市430074

出　　处：《电网技术》2011年第9期210-215,共6页Power System Technology

摘　　要：在分析小电流接地系统中传统小波包选线方法的优势与不足的基础上,提出一种基于多孔算法小波包变换的多频带分量重构自适应选线新方法:首先根据系统运行方式和线路参数确定出选择频带(selected frequency band,SFB)的范围,然后利用多孔算法小波包变换良好的分频特性与保持线性相位的性质,对故障零序电流采样数据进行多尺度分解,自适应地选择落在SFB范围内的多频带分量进行重构,极大限度地提取了有效的故障零序电流分量信息,并构造出能综合利用小波包重构系数幅值与极性信息的选线算法,进一步提高了选线灵敏度。理论分析和大量的PSCAD仿真表明,该方法有效地提高了故障选线的准确性,其灵敏度高,自适应能力强,同时适用于中性点不接地系统和中性点经消弧线圈接地系统。On the basis of analyzing the merit and demerit of traditional wavelet packet-based faulty line detection applied in small current neutral grounding system, a new adaptive faulty line detection approach based on reconstruction of multi-band components, in which the wavelet packet transform of A＇trous algorithm is adopted, is proposed. Firstly, according to system operation mode and parameters of transmission line the range of selected frequency band （SFB） is determined; then utilizing the properties of wavelet packet transform of A＇trous algorithm, namely the good frequency division performance and keeping linear phase, the multi-scale decomposition of sampled zero-sequence component of fault current is performed, and adaptively the multi band components falling into the range of SFB are adaptively chosen, therefore the effective information in zero-sequence component of fault current is extracted as possible; finally, an algorithm to recognize faulty line, which can synthetically utilize the information of amplitudes and polarity of reconstruction coefficients, is constructed, thus the sensitivity of faulty line detection is further improved. Results and a lot of PSCAD simulation show that the proposed method is of high sensitivity and strong adaptive ability; it can effectively improve the accuracy of faulty line detection and is suitable to both isolated neutral system and arc-suppression-coil earthed system.

关 键 词：小电流接地 故障选线 多孔算法小波包 多频带分量重构 故障测度 

分 类 号：TM771[电气工程—电力系统及自动化]