Single-end ranging method for arc light high-resistance earth fault of power transmission line

Abstract

The invention relates to a single-end ranging method for an arc light high-resistance earth fault of a power transmission line. Sampling is carried out continuously on a fault phase current I phi, a zero-sequence current i0 and a fault phase voltage u phi(n) of a power transmission line, steady-state fault data sequences i phi (n), i0 (n), and u phi (n) after the fault are obtained, and a1(n) is calculated; a group of initial parameter solutions (1, UT, IS, and RF)<0> are given and a convergence error r(n) is calculated based on a formula; for a kth iterative solution (1, UT, IS, and RF) <k>, a steepest descent method is used and the solution to a fitting error minimal value is determined in a negative gradient direction as a searching direction; repeated iterative calculation is carried out continuously until an iterative solution (1, UT, IS, and RF)<k+1> of the (k+1)th times meets a given iterative termination principle:|(1, UT, IS, and RF)<k+1>-(1, UT, IS, and RF)<k>| < e, and an optimal solution (1, UT, IS, and RF)<*> is obtained, wherein the corresponding 1 expresses a fault distance. According to the method, on the basis of the characteristics of the fault arc dynamic nonlinearity and high resistance, a logarithm expression of an arc is provided according to the fault arc air discharge essence described by the Thompson principle. A defect that traditional arc differential equation calculation can not be used by the fault ranging algorithm directly can be overcome; and the practical flexibility is high.

Description

technical field [0001] The invention belongs to the technical field of power system protection and control, and in particular relates to a single-end distance measuring method for arc-light high-resistance grounding faults of transmission lines. Background technique [0002] Affected by factors such as the natural environment, high-resistance grounding faults of various forms of transmission lines have occurred frequently in recent years, such as insulator flashover, lightning strikes, wildfires, grounding through automobile tires, etc., resulting in multiple primary protection faults such as differential, distance, and zero-sequence currents. Action delay or even refusal accidents occur frequently, while high-resistance ground faults are mostly accompanied by arcing, which can easily cause fires and cause serious losses of life and property. The difficulty of this type of fault analysis is that it is difficult to grasp the dynamic nonlinear characteristics of the arc at the...

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Problems solved by technology

[0005] In order to overcome the defect that the traditional arc differential equation is iteratively calculated and difficult to be directly applied by the fault location algorithm, the purpose of the present invention is to provide a single-ended fault location method for arc high-resistance grounding faults on transmission lines, based on the fault arc air described by Thomson's principle. The nature of the discharge, the logarithmic expression of the arc is given, and combined with the traditional time-domain impedance method fault location algorithm, the fault distance is calculated according to the voltage and current signals collected by the line and the known line parameters

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