Power distribution network single-phase earth fault line selection method based on line double-terminal negative sequence current

Abstract

The invention belongs to the field of power system relay protection technology, and provides a power distribution network single-phase earth fault line selection method based on line double-terminal negative sequence current. The power distribution network single-phase earth fault line selection method is characterized in that the method includes the steps of firstly carrying out synchronous sampling to three-phase current of head ends and tail ends of all circuits to be judged in a power distribution network, and then calculating negative sequence current components at the head ends and the tail ends of the circuits according to sampling results; the negative sequence current components at the head ends and the tail ends of normal circuits are equal, while the negative sequence current components at the head ends and the tail ends of the circuits with a single-phase earth fault are different, so that a criterion for fault line selection is formed. The calculation and analysis to a representative 35-kilovolt multi-branch power distribution network single-phase earth fault indicates that the power distribution network single-phase earth fault line selection method can be used for choosing the faulty circuits accurately in a sensitive mode, and can be widely applied to the power distribution network with various earthing methods, and the line selection principle is not influenced by arc suppression coils.

Description

technical field [0001] The invention belongs to the technical field of electric power system relay protection, and in particular relates to a single-phase ground fault line selection method applied to a power distribution network. Background technique [0002] Single-phase grounding is the most likely fault in distribution network, accounting for about 80% of all faults, but the selection of single-phase grounding fault line in distribution network has always been a technical problem that plagues people. Because the fault current is small and the fault characteristics are not obvious, it is more difficult to select the fault line of the distribution network whose neutral point is grounded through the arc suppressing coil. [0003] In recent years, scholars have proposed many line selection methods and developed a series of line selection devices, and there are many invention patents related to this technology. The line selection method based on the fault transient electrica...

AI Technical Summary

Problems solved by technology

When the grounding resistance is high, the single-phase grounding fault has very little influence on the power flow in the system, and this method will be useless

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