Fault line selection method of distribution network based on cascaded bistable system

Abstract

The invention provides a distribution network fault line selection method based on a cascade bistable system. The method comprises the steps that 1 a potential function parameter in the cascade bistable system is set; 2 the acquired transient zero sequence current in(t), which includes noise, of each line is normalized to acquire normal zero sequence current gn(t); 3 s(t)+gamma(t) in the potential function parameter y(t) is set as gn(t); a fourth-order Runge-Kutta algorithm is used to solve yn(t); and yn(t) is reverse-normalized to acquire process characteristic zero sequence current rn(t); 4 after yn(t) is acquired, the fourth-order Runge-Kutta algorithm is used to solve X, and the acquired X is called as second-order current sn(t); 5 sn(t) is reverse-normalized to acquire the transient characteristic zero sequence current cn(t) of each line; 6 the cross-correlation coefficient matrix rho n of each line cn(t) is calculated; 7 a polarity parameter Jn and an energy parameter En are acquired; and 8 the line selection distance dn is defined, and the maximum line of dn is determined as a faulty line. According to the invention, in a strong noise background, fault line selection is accurate, and the method has a good performance in various different fault situations.

Description

technical field [0001] The invention belongs to the field of fault line selection of power system distribution network, in particular to a fault line selection method of distribution network. Background technique [0002] The fault line selection of the distribution network has the following difficulties and problems: 1) The fault characteristics of the signal are not obvious: after a single-phase ground fault, the steady-state current is generally less than 30A or even only a few A. In addition, the complex structure of the distribution network sometimes leads to fault characteristics Not obvious, although the fault transient zero-sequence current signal is larger than the steady-state zero-sequence current signal, but the duration is short, and sometimes it is difficult to detect; It will also change frequently, and the harmonic current and distributed capacitance current of its line will also change accordingly. In addition, factors such as the intensity of external nois...

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Problems solved by technology

[0002] The fault line selection of the distribution network has the following difficulties and problems: 1) The fault characteristics of the signal are not obvious: after a single-phase ground fault, the steady-state current is generally less than 30A or even only a few A. In addition, the complex structure of the distribution network sometimes leads to fault characteristics Not obvious, although the fault transient zero-sequence current signal is larger than the steady-state zero-sequence current signal, but the duration is short, and sometimes it is difficult to detect; It will also change frequently, and the harmonic current and distributed capacitive current of its line will also change accordingly.

However, the existing literature only selects the potential function parameters based on experience, which may lead to inaccurate characteristic signals extracted by stochastic resonance, which greatly affects the application effect of stochastic resonance

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