中性点非直接接地电网单相接地故障暂态特征分析

针对已有暂态分析方法存在的不足，建立了基于线路分布参数模型的小电流接地故障模量结构图；根据线路相频特性将频率分为不同区段，再分析不同频段内故障暂态特征。重点论证了零序网络在一选定频段(SFB)下阻抗呈容性的特性及其临界频率应满足的条件，分析了在该选定频段内暂态零序电流及无功功率的分布规律，得出以下结论：在SFB内，故障线路暂态零序电流和无功功率大于或等于任何一条健全线路，且在故障线路中从线路流向母线，与健全线路中的流向相反；在SFB外，故障线路和健全线路电气量分布差异不明显或临界频率不易确定。用电磁暂态仿真程序(ATP)对故障暂态特征进行了验证。

Analysis of Transient Characteristics of Signals Phase Earth Fault in Non-Solidly Earthed Network

The modal network of single phase earth fault in non-solidly earthed network based on feeders' distributed parameters is constructed to overcome the deficiency of traditional transient analysis methods. The characteristics of transient zero sequence voltage and current produced by earth fault in different frequency bands,which can be decomposed according to angle-frequency characteristics of feeders' detected impedance,are analyzed. It is found that the impedance of zero sequence network is capacitive in the selected frequency band (SFB), and it's boundary frequencies are given. The distribution of transient zero sequence current and reactive power within SFB is presented. The zero sequence current and reactive power of the faulty feeder within SFB are larger than or equal to any healthy feeders in amplitude. The flow direction is from the feeder to the bus in faulty feeders and opposite in healthy feeders. The fault transient characteristics are verified by simulation results using ATP (alternative transient program).