文档介绍：小电流接地系统配电网单相接地保护方法探讨及
各种保护方法的理论计算和比较分析
摘要
我国的中压电网基本上都是小电流接地系统(NUGS),它包括中性点不接地系统(NUS)和经消弧线圈接地系统(NES),NUGS中单相接地故障率最高, 而由于单相接地时故障电流小，信号微弱，使得NUGS的单相接地故障选线一直未能得到有效的解决。论文在参考国内外诸多文献的基础上,探讨分析了现有各种选线方法的原理与利弊。
首先，本文对中性点经消弧线圈接地系统的特点及其零序暂态电流作了理论计算分析，得出其零序全电流表达式。
其次，本文对基于系统故障信号检测的选线方法原理进行了分析比较，得出零序导纳法较为有效的克服了过渡电阻的影响，在理论上应该优于其他方法。
再次，本文对外加信号的几种选线方法进行了分析比较，由此得出只有根据系统的运行工况有机地将各种理论完美地结合起来，扬长避短，才能达到满意的效果。
最后，还对本文作了总结，并对小电流接地系统单相故障选线方法的研究作出展望。
关键词：小电流接地系统；过渡电阻；零序全电流
The small electric current connects a ground of
system to go together with the charged barbed
wire net list to connect a ground of protection
method study and various theories of protection
method calculations and comparisons analysis
ABSTRACT
Middle voltage distribution power systems in our country are almost ineffective grounded systems(NUGS) ， which include isolated neutral networks(NUS) and networks grounded with the neutral compensator coil (NES).The coefficient of single phase-to-ground fault is very high in NUGS, but the faulty current is so small that fault line selection problem has not been solved effectually until today. Based on many literatures of China and foreign countries, the principles and traits of current schemes are discussed and analyzed in this paper.
At first, I will calculate and analyse the neuter point connecting with the ground by arc-reducing winding, giving its zero-sequence current express type.
The second,! will compare and analyse the methods base on examinating fault message. It is got that the method of zero-sequence Electric conductivity can overcame the influence of the transition resistance is better than other method theoretically.
The third,! will compare and analyse the methods In addition signal.
At last,! will Summary this Article and Outlook the methods of Small current neutral grounding system.
Key word: Small current neutral grounding system； Transition resistance； Zero-sequence current
目录
摘要
ABSTRACT II
第一章绪论 1