Power distribution network fault line selection method based on variable-scale bi-stable system

Abstract

The invention relates to a power distribution network fault line selection method based on a variable-scale bi-stable system. The method comprises steps as follows: firstly, after a distribution network has a single-phase earth fault, transient-state zero-sequence current izn(t) from one cycle before the fault to one cycle after the fault of each branch line is selected; then parameters a and b of a potential function in the variable-scale bi-stable system as well as numerical values of a four-order Runge-Kutta equation are set for calculation of step length hs; then the izn(t) is transformed correspondingly according to the amplitude of the izn(t), the transformed izn(t) replaces s(t) in an expression of the variable-scale bi-stable system, the four-order Runge-Kutta equation is used for solving, and the obtained solution is an overall feature signal isn(t); then data, from 0.02 s to 0.025 s, of the overall feature signal isn(t) are selected as feature current; finally, distribution network fault line selection is performed by the aid of plus-minus signs of cross correlation coefficients of the feature current of all lines: if signs of the cross correlation coefficients of a certain line are identical, minus 1 is output, and the line is judged as a fault line; if signs of the cross correlation coefficients of a certain line are different, 1 is output, and the line is judged as a non-fault line.

Description

technical field [0001] The invention relates to a fault line selection method of a distribution network based on a variable-scale bistable system, and belongs to the field of fault line selection of a power system distribution network. Background technique [0002] As an important part of the power system, the distribution network has the closest connection with users and the most direct impact on users. Statistics show that most of the faults in the power system occur in the distribution network, and 80% of the faults in the distribution network are single-phase ground faults. When a single-phase ground fault occurs, the line voltage is still symmetrical and the fault current is weak. Short-term operation for 1 to 2 hours after a fault can significantly improve the reliability of power supply. However, during a single-phase-to-ground fault, the rise of the non-fault phase-to-ground voltage will threaten the insulation of the system, which will easily lead to the developmen...

AI Technical Summary

Problems solved by technology

The so-called stochastic resonance is a new technology with practical application value that applies the principle of stochastic resonance (such as a bistable system) for weak signal enhancement detect

Images