Method for carrying out line selection on low-current grounded fault traveling waves

Abstract

The invention relates to a method for carrying out line selection on low-current grounded fault traveling waves. The method comprises the following steps of S1, separating three-phase initial voltage traveling waves of a bus from initial current traveling waves of all outgoing lines within a certain time T after a fault happens; S2, detecting a wave head amplitude value, and using the wave head amplitude value to express the initial voltage traveling waves and the initial current traveling waves; S3, carrying out the line selection by using the initial current traveling waves to judge a fault line; S4, carrying out phase selection by using the initial voltage traveling waves to judge a fault phase. According to the method disclosed by the invention, after a power distribution network is in single-phase grounded fault, the fault line can be judged by comparing the same-phase initial current traveling waves of all the outgoing lines, and the fault phase can be judged by comparing the three-phase initial voltage traveling waves in the bus; the method cannot be affected by the grounding mode of a neutral point, the size of a transition resistor, whether a branch line exists or not, whether the branch line is a mixed line or not or whether the line is unloaded or not, the fault phase can be selected while the fault line is selected, and the method has practical engineering value.

Description

technical field [0001] The invention relates to a traveling wave line selection method for a small current grounding fault, belonging to the technical field of protection and control of distribution networks. Background technique [0002] Most of the 35KV and 10KV power distribution systems in our country adopt the treatment method that the neutral point is not grounded or the arc suppression coil is grounded. Due to the small fault current and the unstable grounding process caused by arc light, single-phase ground fault detection has been difficult to solve completely. [0003] In the neutral point ungrounded power grid, when the single phase is grounded, the power frequency zero-sequence current of the fault line is equal to the sum of the capacitance currents of all healthy lines to the ground, and the direction is from the line to the bus. The zero-sequence current of a sound line is equal to its own capacitance current to the ground, and the direction is from the busba...

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is: aiming at the line selection problem of small current grounding faults in distribution network, overcoming the shortcomings of traditional algorithms with low reliability, and providing a small current grounding fault traveling wave for line selection based on transient traveling waves Line selection method

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