A method for detecting and automatically correcting the polarity of zero-sequence current in line selection

Abstract

A method for detecting and automatically correcting the polarity of zero-sequence current for line selection, which connects a small-current grounding line selection device and a zero-sequence current transformer; the small-current grounding line selection device passes through the self-test voltage input terminal and the self-test current input terminal Collect the amplitude and phase of self-test voltage and self-test current, and compare the phase difference between self-test voltage and self-test current. If the phase difference is near 0 degrees, it is judged that the wiring is correct; if the phase difference is near 180 degrees, it is judged that the wiring is wrong , correct after judging that the wiring is wrong; initialize the correction flags of all access lines to 0, then perform XOR operation on the correction flags of all wrong access lines and 1 to obtain a new correction flag, and then correct all wrong access lines The phase correction is performed on the incoming lines, specifically, the correction flags of all wrong incoming lines are multiplied by the correction angle 180 to perform correction, and the correction results are memorized. The method can quickly detect the polarity state of the zero-sequence transformer, and can automatically correct the reversed circuit.

Description

technical field [0001] The invention belongs to the technical field of single-phase grounding protection and protection, and in particular relates to a method for detecting and automatically correcting the polarity of a line selection zero-sequence current. Background technique [0002] When a single-phase ground fault occurs in a low-current grounding system, the fault current is relatively small, and it can operate with the fault for a period of time, but the single-phase ground fault is likely to cause the normal phase voltage to rise, which may lead to insulation breakdown and cause faults. Therefore, when a single-phase ground fault occurs, the faulty line must be quickly detected and eliminated. [0003] The existing line selection algorithm has requirements for the phase of zero-sequence voltage and zero-sequence current, so the wiring needs to be correct. However, the existing line selection devices generally have a large number of lines, and the positions of the wi...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problems existing in the above-mentioned prior art, the present invention provides a method for detecting and automatically correcting the polarity of the zero-sequence current in line selection, which can quickly detect the polarity state of the zero-sequence transformer, and can automatically correct the reversed circuit It can effectively avoid time-consuming and labor-intensive situations in the process of manual line checking and line adjustment

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