摘要
根据线路的相频特性将频率分为不同的区段,论证了在选定频段(SFB)内,小电流接地系统健全线路零序电流极性与故障线路相反;应用小波包以适当频率带宽对各线路的暂态零序电流进行分解,小波包系数的符号表示相应频段零序电流的极性;在SFB内按照能量最大的原则,确定各线路暂态零序电流分布最集中的频带所对应的小波包分解树节点,通过比较所有线路暂态零序电流在各自能量最大节点处的小波包分解系数的极性,自适应地实现故障选线。PSCAD仿真试验结果表明,该方法能够准确、可靠地实现电缆—架空线混合传输线的小电流接地系统单相故障选线。
In view of the distribution of different frequency in terms of phase-frequency characteristic, the polarity of zero sequence transient current in fault line is demonstrated to be opposite to those in healthy feeders in the selected frequency band (SFB). Wavelet packet is then used to decompose the zero sequence transient current and the signs of coefficients of wavelet packet represent the polarities of currents in corresponding frequency bands. The decomposition tree nodes of wavelet packet for the most centralized distributing frequency band can be ascertained according to the principle of maximum energy within the SFB. The fault line selection is therefore adaptively done by comparing the polarities of the zero sequence transient currents in all lines at the node containing the each maximum energy. The PSCAD simulation results show that the method proposed can accurately and reliably carry out the fault line selection in hybrid cable-overhead line non-solidly earthed network.
出处
《电力系统自动化》
EI
CSCD
北大核心
2007年第4期76-79,84,共5页
Automation of Electric Power Systems
关键词
相频特性
多频带分析
小电流接地系统
单相接地故障选线
小波包
暂态零序电流
phase-frequency characteristic
multi-frequency band analysis
non-solidly earthed network
single-phase-to-ground fault line selection
wavelet packet
zero sequence transient current