Low-current single-phase earth fault detection method for 10KV distribution network

Abstract

The invention discloses a low-current single-phase earth fault detection method for a 10KV distribution network. The method comprises the steps of (1) data acquisition: tracking and accumulating outgoing line scheduling measurement data and line marketing TTU / load control data of the distribution network line in a normal operation state for a long time so as to calculate the power loss level of each distribution network outgoing line under different loads; (2) establishing a normal loss model of each distribution network outgoing line and an earth fault loss model during single-phase earthingby analyzing correlations among various variables; and (3) judging the fault phase line according to the measurement of the secondary side voltage value of the open triangle PT of each transformer substation bus. According to the invention, the steady-state big data analysis method for automatic operation monitoring of the 10KV distribution network line is realized to perform line selection and fault identification prediction of the small-current earth fault.

Description

technical field [0001] The invention relates to a small-current single-phase ground fault detection method for a 10KV distribution network, belonging to the technical field of low-current single-phase ground fault detection. Background technique [0002] At present, most of my country's 10KV power system adopts a three-phase neutral point ungrounded system design: that is, except for the distributed capacitance of the 10KV distribution network power equipment itself, which can be grounded, the others are not grounded. The advantage of this distribution network system design is that when a ground fault occurs, the fault current is small, and the damage to the power equipment will not be serious. Therefore, in the case of single-phase grounding without forming a short-circuit loop, it can continue in accordance with the power operation regulations. Run for 1-2 hours. The disadvantage is that when a single-phase ground fault occurs, an instantaneous overvoltage may occur, whic...

AI Technical Summary

Problems solved by technology

The disadvantage is that when a single-phase ground fault occurs, an instantaneous overvoltage may occur, which poses a threat to equipment and personal safety. This requires the distribution network operation and management personnel to quickly find the faulty line and cut it off, otherwise it will cause a fault. Expansion endangers the safety of power systems and equipment

Due to the influence of noise, harmonic interference and other factors, the zero-sequence electrical quantity collected by the line selection device, regardless of the amplitude or phase angle, may not satisfy the above relationship, resulting in misjudgment and missed judgment.

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