Small current grounding system high-resistance grounding fault line selection method based on comparison between transient projection component amplitude and polar relationship

Abstract

A small current grounding system high-resistance grounding fault line selection method based on comparison between transient projection component amplitude and a polar relationship belongs to the field of power distribution network fault detection. The invention settles a problem of small current grounding system high-resistance grounding fault line selection and provides the line selection method based on projection component amplitude comparison of transient current of each feed line on transient voltage of a bus and polar relationship determining. The method comprises the steps of after a zero-sequence voltage amplitude of a bus exceeds a fixed value, acquiring the outlet zero-sequence current of each feed line of a power distribution network, and extracting the transient components of the outlet zero-sequence current and the bus zero-sequence voltage of each feed line; performing projection of the outlet transient zero-sequence current of each feed line on the transient zero-sequence voltage of the bus; comparing the amplitude of the outlet transient zero-sequence current projection component of each feed line, and selecting a plurality of lines with highest projection component amplitudes as candidate faulted lines; and selecting the feed lines with polarities which are reversal with that of transient current projection components of other candidate feed lines, wherein a bus fault is judged on the condition that the transient current projection of all the candidate feed lines have the same polarity. The small current grounding system high-resistance grounding fault line selection method settles a line selection problem of a high-resistance grounding fault in a small current grounding system and has high application value.

Description

technical field [0001] The invention relates to a high-resistance fault line selection method for a small-current grounding system, which is suitable for a power distribution system in a small-current grounding mode, and belongs to the field of distribution network fault detection. Background technique [0002] Since the medium-voltage distribution network directly faces users, and single-phase grounding accounts for about 80% of the total distribution network faults, the reliable detection of single-phase grounding faults has a significant impact on power supply reliability. In China and continental Europe, most of the medium-voltage distribution network adopts the grounding method of the arc suppression coil, which is the so-called resonant grounding system. When a single-phase ground fault occurs, it is not necessary to remove the fault immediately, which is conducive to improving the reliability of power supply. However, due to the weak fault current and other reasons, i...

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Problems solved by technology

[0006] The purpose of the present invention is to solve the problem of fault line selection when high-impedance grounding occurs in a small current grounding system, and propose a selection method based on the comparison of the projected component amplitudes of the transient currents of each feeder line on the transient voltage of the busbar and the determination of the polarity relationship. line method

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