小电流接地系统单相接地故障选线的研究

为提高单相接地故障选线的准确性,从国内外小电流接地系统单相接地选线原理和装置的实际应用情况出发,深入分析得出单相接地故障的复杂性和单选线原理的单一性、保护裕度低是影响现有单相接地故障选线准确性、可靠性的原因,因此利用电弧接地故障时各线路零序暂态电流的特征提出了暂态电流互积求和选线法,针对稳态接地故障的特征提出了导纳互差求和选线法,并利用这两种分别基于稳态和暂态接地故障的选线方法构成能够针对不同类型接地故障的综合选线方法,从而克服了接地选线原理的单一性。采用该综合选线方法,设计开发出了相关微机选线装置。大量的6kV电网模拟试验和实际电网运行情况表明,该综合选线方法能有效的提高选线的准确性和可靠性。

Single-phase-to-ground Fault Protection for Indirect Grounding Power System

This paper analyses deeply the reasons that effect fault line detection accuracy and dependability from the one-phase-to-ground fault line detection theory for indirect grounding power system.The synthetic detecting fault feeder method is put forward on the basis of the method of summation of mutual integral of transient current for intermittent arc-earth fault using the characteristic of the feeders zero-sequence transient current and the method of summation of admittance mutual difference for steady earth fault.And the synthetic criteria are presented based on arc-earth fault and steady earth fault.And this method eliminates the singleness of fault line detection theory.Composite criteria with microcomputer line detection instrument are developed based on above-mentioned method.The experimental results and field operation show that this method can increase the accuracy and the dependability of detecting fault line effectively.