High-resistance grounding phase selection method for longitudinal zero-sequence protection of line protection device

Abstract

The invention discloses a high-resistance grounding phase selection method for longitudinal zero-sequence protection of a line protection device. The method comprises the following steps of: firstly, when a line fails, detecting whether the failure is a line grounding failure, and determining the failure type of the line grounding failure according to a phase ratio criterion method; and secondly, according to criteria of the motion direction of a zero-sequence directional element and three phase voltage values and a one-way phase determination criterion method, determining that the failure type is the phase of a single-phase high-resistance grounding failure. By adoption of the phase selection method for the longitudinal zero-sequence protection during high-resistance grounding, the phase of the single-phase high-resistance grounding failure of the longitudinal zero-sequence protection can be conveniently and quickly obtained, and the phase selection tripping of the longitudinal zero-sequence protection is realized, so the line protection device is applicable to an ultra-high-voltage line employing a single-phase re-turn-on mode and has a good application prospect.

Description

technical field [0001] The invention belongs to the field of electrotechnical technology, and in particular relates to a high-impedance grounding phase selection method for longitudinal zero-sequence protection integrated with line protection devices. Background technique [0002] Among the line protection devices in the power system, the longitudinal distance protection device is the main protection device for lines with a voltage level of 220kV and above. Due to the poor ability of the distance element to withstand transition resistance, the longitudinal distance protection device generally integrates the longitudinal zero-sequence The protection is used to cut off the high-resistance grounding fault of the line. We know that the zero-sequence protection itself does not have the ability to select phases, but the ultra-high voltage line adopts a single-phase reclosing method, so the longitudinal zero-sequence protection is required to have the function of phase-selection tri...

AI Technical Summary

Problems solved by technology

[0003] The technical problem solved by the present invention is to overcome the problem that the line protection device in the prior art often adopts a phase selection method based on zero-negative-sequence current phase partition to select the grounding area for grounding faults, but the specific phase difference cannot be determined, and it cannot be applied to adopting a single phase selection method. Problems of Phase Reclosing EHV Lines

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