基于零序等效电导的故障选线方法

发布时间：2018-10-30 08:46

【摘要】：单相接地故障通常伴随电弧接地,电弧接地产生大量谐波,配电网非线性负载也会产生谐波,谐波直接导致故障零序电压、电流畸变,现有的信号分析方法不能准确的对故障畸变信号进行分解,直接影响现有故障选线方法的准确性。论文采用适用于畸变信号的数学分析方法计算分析含谐波的单相接地故障信号,可有效提高故障选线的可靠性,对保证配电网的安全运行具有重要意义。论文研究了在畸变电压、电流作用下,利用Fryze非正弦分析方法分解畸变故障信号的优势。分别分析了中性点不接地运行方式下和中性点经消弧线圈接地运行方式下,故障线路和非故障线路等效电导与零序谐波电压频率、零序谐波电流畸变率等的影响关系,推导出当系统发生单相接地故障时,故障线路零序等效电导大于非故障线路零序等效电导的结论的结论。在此基础上,论文选用零序等效电导作为故障特征参数来辨识接地线路,在matlab仿真平台上编写并实现了单相接地故障选线算法。采用Fryze电流分解方法计算单相接地故障的零序等效电导时能够将谐波因素考虑在内,该方法不受中性点运行方式的影响,尤其适合于对单相弧光接地故障的辨识。论文通过改变配电网不同的中性点接地方式、不同的线路参数、不同的谐波环境等条件,利用论文的选线方法对单相接地故障进行仿真分析,结果表明该选线方法均能准确选出故障线路,验证了论文选线方法的可靠性。
[Abstract]:Single phase grounding fault is usually accompanied by arc grounding, arc grounding produces a large number of harmonics, distribution network nonlinear load will also produce harmonic, harmonic directly lead to fault zero sequence voltage, current distortion, The existing signal analysis method can not decompose the fault distortion signal accurately, which directly affects the accuracy of the existing fault line selection method. In this paper, the mathematical analysis method suitable for distortion signal is used to calculate and analyze the single-phase grounding fault signal with harmonics, which can effectively improve the reliability of fault line selection, and is of great significance to ensure the safe operation of distribution network. In this paper, the advantage of decomposing the distorted fault signal by Fryze non-sinusoidal analysis method under the action of distorted voltage and current is studied. The relationship between the equivalent conductance of fault line and non-fault line and the frequency of zero-sequence harmonic voltage, the distortion rate of zero-sequence harmonic current and so on are analyzed respectively under neutral ungrounded operation mode and neutral point grounding mode through arc-suppression coil. The conclusion that the zero sequence equivalent conductance of the fault line is greater than the zero sequence equivalent conductance of the non fault line is deduced when the single phase grounding fault occurs in the system. On this basis, zero sequence equivalent conductance is selected as the fault characteristic parameter to identify the earth wiring, and the algorithm of single-phase grounding fault line selection is compiled and implemented on the matlab simulation platform. The harmonic factor can be taken into account when Fryze current decomposition method is used to calculate the zero-sequence equivalent conductance of single-phase grounding fault. This method is not affected by the operation mode of neutral point and is especially suitable for identification of single-phase arc grounding fault. By changing different neutral grounding modes, different line parameters, different harmonic environment and other conditions of distribution network, the paper uses the method of line selection to simulate and analyze single-phase grounding fault. The results show that the fault lines can be selected accurately by this method, and the reliability of the method is verified.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM862

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