Single-phase grounding double-end detecting positioning method for overhead line of power distribution network

Abstract

The invention discloses a single-phase grounding double-end detecting positioning method for an overhead line of a power distribution network. The method comprises the following steps of (A), selecting bus ends at two sides of a trunk line of the power distribution network as detecting ends, respectively sampling for obtaining stable-state three-phase voltage of the two detecting ends before a fault, and fault-state three-phase voltage of the two detecting ends in the fault; (B), performing Karenbauer phase-mode conversion on the fault-state three-phase voltage of the two detecting ends obtained in the step (A), and obtaining line mode voltage; (C), performing generalized S transformation on the line mode voltage obtained in the step (B), and performing energy characteristic extraction bymeans of a Teager energy operator, and obtaining time points in arriving at the two detecting ends by a travelling wave front at two front times; and (D), by means of the time points in arriving at the two detecting ends by the traveling wave front at two front times, performing comprehensive analysis through calculation and determining, thereby obtaining a distance to the fault. The method realizes accurate detection to the traveling wave front and furthermore realizes accurate fault positioning.

Description

technical field [0001] The invention relates to the field of single-phase ground fault location in distribution network, in particular to a single-phase ground double-terminal detection and location method for overhead lines in distribution network. Background technique [0002] Single-phase ground fault is the most likely fault in distribution network. my country's 6-35kV distribution network generally adopts a low-current grounding method. After a single-phase ground fault occurs, it can continue to operate with the fault for a period of time. However, if the fault point is not quickly and accurately eliminated, the line insulation system is easily damaged, resulting in the expansion of the accident. , affecting the safe and reliable operation of the system. [0003] However, the network structure of the distribution network is mostly dendritic and radial, with many branches and relatively short line lengths. It is very difficult to detect and locate faults, which is a wor...

AI Technical Summary

Problems solved by technology

In practical applications, the most widely used method is the double-terminal traveling wave ranging method. This method uses the time when the fault traveling wave signal generated at the fault location reaches the detection points at both ends of the line to locate the fault point. The traveling wave signal is a non-stationary high-frequency transient signal, which is easily disturbed by noise and difficult to detect the signal

Time-frequency analysis is an effective method to extract the characteristics of non-stationary signals. At present, the typical time-frequency analysis algorithms for detecting traveling wave heads include wavelet transform, Hilbert-Huang transform and S transform. Due to the inherent disadvantages of their respective methods, they cannot be accurately detected. wave head

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