Single-phase disconnection fault line selection method for traditional distribution network

Abstract

The invention discloses a single-phase disconnection fault line selection method for a traditional distribution network. The method comprises the following steps: calculating the negative sequence current of each feeder by use of a symmetrical component method; when the amplitude of the negative sequence current is greater than a negative sequence setting value, performing EMD decomposition on the negative sequence current of each feeder to get an intrinsic mode component IMF at each order; performing Hilbert transform on the intrinsic mode component IMF at each order to get a corresponding instantaneous amplitude waveform; calculating the variation of the sum of instantaneous amplitudes of m cyclic waves for the intrinsic mode component IMF at the set order of each feeder before and after fault; and selecting a disconnection fault line according to the variation. The line selection criterion chosen in the invention is effective in all kinds of neutral point grounding modes. The method is not affected by load characteristics, can be used to detect a single-phase disconnection fault under a line driving force load, a non-dynamic load or a comprehensive load, and is of high reliability.

Description

technical field [0001] The invention relates to the technical field of distribution network fault line selection, in particular to a traditional distribution network single-phase disconnection fault line selection method. Background technique [0002] Because the fault current is not obvious and the fault characteristic quantity is difficult to detect, the disconnection fault has little harm to the power transmission and transformation equipment, and the degree of attention in the operation and maintenance of the power grid is far less than that of the short-circuit fault. Due to the characteristics of the distribution line itself, when a single-phase disconnection fault occurs on a feeder, the changes in the bus phase voltage and phase current are not obvious, so it is not easy to be found, but continuous asymmetric operation will have adverse effects on users. In non-full-phase operation, although the consequences are generally smaller compared with short-circuit faults, t...

AI Technical Summary

Problems solved by technology

However, the voltage and current changes caused by disconnection faults are not obvious, so the sensitivity of the disconnection protection criterion based on the above-mentioned electrical quantity change characteristics is not high.

Images