A Method of Line Selection and Phase Selection for Small Current Grounding Based on Fault Sequence Components

Abstract

The invention discloses a small current grounding line selection and phase selection method based on fault sequence components, which comprises the following steps: (1) collecting bus zero-sequence voltage, and starting grounding line selection discrimination when the zero-sequence voltage exceeds a set threshold; (2) ) to extract the three-phase current components in the line and calculate the size of the corresponding positive sequence, negative sequence and zero sequence components, respectively (3) based on the current component calculated in step (2) and its sequence component to construct a relational group, according to As a result, the faulty line and faulty phase are discriminated sequentially for this line. The present invention does not depend on the zero-sequence current when discriminating the grounding line, and only uses the three-phase current of the line protection itself to select the line and phase, avoiding the wrong line selection caused by the wrong connection of the secondary circuit. At the same time, it also eliminates the influence of the imbalance of the system itself and the line load on the line selection, effectively improves the accuracy of the grounding line selection, and has broad application prospects.

Description

technical field [0001] The invention belongs to the technical field of power system automation, and in particular relates to a small current grounding line selection and phase selection method based on fault sequence components. Background technique [0002] Most of my country's 6-66kV distribution network adopts the low-current grounding operation mode. After a single-phase grounding fault occurs in the small-current grounding grid, it will not produce a large short-circuit current, but there are also considerable hazards. In order to establish a safe and good If there is a power environment, the grounding line should be found as soon as possible and removed. The grounding line selection device configured in the traditional substation basically depends on the zero-sequence current and zero-sequence voltage when the line selection is judged. When the secondary circuit has a wiring error and the polarity of the zero-sequence current is reversed, the impact on the line selectio...

AI Technical Summary

Problems solved by technology

The grounding line selection device configured in the traditional substation basically depends on the zero-sequence current and zero-sequence voltage when the line selection is judged. When the secondary circuit has a wiring error and the polarity of the zero-sequence current is reversed, the impact on the line selection is fatal

At the same time, when the imbalance of the system itself leads to the existence of non-negligible zero-sequence current and zero-sequence voltage, it will also affect the result of line selection when an actual fault occurs

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