Least square and correlation analysis-based line arrester action recognition method

A line arrester and related analysis technology, applied in character and pattern recognition, instruments, indicating the existence of current/voltage, etc., to achieve the effect of accurate and reliable judgment results

Active Publication Date: 2018-02-16
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The surge arrester at the station monitors the leakage current and the number of operations in real time, but the arresters along the line are g

Method used

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  • Least square and correlation analysis-based line arrester action recognition method
  • Least square and correlation analysis-based line arrester action recognition method
  • Least square and correlation analysis-based line arrester action recognition method

Examples

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Embodiment 1

[0042] Embodiment 1: as figure 1 As shown in Fig. 1, an action identification method for line arresters based on least squares and correlation analysis, when the transmission line is struck by lightning, the lightning current waveform is measured at the measurement end; the wavelet modulus maximum transform is used for the measured lightning current waveform , determine the arrival time of the initial traveling wave of the fault; according to the falling edge of the initial traveling wave head, use the least squares method to fit the arrester's non-action curve; choose a suitable time window, and compare the lightning current waveform measured at the measuring end The correlation analysis coefficient of the action curve is obtained by correlation analysis. The threshold value of the correlation coefficient is 0.9. If the correlation analysis coefficient is greater than 0.9, the line arrester does not operate. If the correlation analysis coefficient is less than or equal to 0.9,...

Embodiment 2

[0065] Embodiment 2: as figure 2 As shown, on the basis of Example 1, further, a simulation model of a 220kV transmission line is established based on the PSCAD / EMTDC electromagnetic transient simulation platform. The transmission line adopts a frequency variable parameter model, and the simulation sampling step is 1 μs; Exponential wave lightning current model, insulator model discharge voltage U 50％ as a criterion. Lightning directly strikes the insulator of the transmission line and a flashover occurs, and the line arrester is installed 400m away from the flashover point of the insulator and operates.

[0066] The original waveform of lightning flashover collected by the measurement terminal is as follows: figure 2 The solid line shown in, figure 2 The dotted line in is the curve based on the least squares fitting, through MATLAB software figure 2 The solid line and dotted line in the correlation analysis, the correlation coefficient ρ is 0.59, that is, the action o...

Embodiment 3

[0067] Embodiment 3: as image 3 As shown, on the basis of Example 1, further, a simulation model of a 220kV transmission line is established based on the PSCAD / EMTDC electromagnetic transient simulation platform. The transmission line adopts a frequency variable parameter model, and the simulation sampling step is 1 μs; Exponential wave lightning current model, insulator model discharge voltage U 50％ as a criterion. Lightning directly strikes the insulator of the transmission line and flashover occurs, and the line arrester is installed 900m away from the flashover point of the insulator and operates.

[0068] The original waveform of lightning flashover collected by the measurement terminal is as follows: image 3 The solid line shown in, image 3 The dotted line in is the curve based on the least squares fitting, through MATLAB software image 3 The solid line and dotted line in the correlation analysis, the correlation coefficient ρ is 0.51, that is, the action of the ...

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Abstract

The invention relates to a least square and correlation analysis-based line arrester action recognition method, and belongs to the technical field of power system relay protection. The method comprises the following steps of: when a transmission line encounters a lightning stroke, measuring a lightning stroke current waveform by a measurement end; transforming the measured lightning stroke currentwaveform by utilizing a wavelet modulus maximum value so as to determine an arrival moment of a faulted initial traveling wave; fitting an unacted curve of an arrester by utilizing a least square method according to a wave head falling edge of the initial traveling wave; selecting a proper time window, carrying out correlation analysis on the lightning stroke current waveform measured by the measurement end and the fit unacted curve of the arrester to obtain a correlation analysis coefficient, the threshold value of which is 0.9, if the correlation analysis coefficient is greater than 0.9, considering that the line arrester does not act, and if the correlation analysis coefficient is smaller than or equal to 0.9, considering that the line arrester acts. The method is not influenced by thefactors such as lightning stroke type, lightning stroke line positions and lightning current amplitude, and is correct and reliable in judgement result.

Description

technical field [0001] The invention relates to an action identification method of a line arrester based on least squares and correlation analysis, and belongs to the technical field of electric power system relay protection. Background technique [0002] At present, in order to improve the lightning resistance level of transmission lines, lightning protection measures such as reducing the grounding resistance, reducing the protection angle, installing lightning rods on the top of the tower, strengthening line insulation, erecting lightning protection lines, erecting coupling ground wires, and installing lightning arresters along the line are often taken. Installed at the entrance or exit of the substation and some towers along the line (high terrain, heavy minefields, locations where lightning flashovers have occurred in history), the arrester will operate when the overvoltage caused by lightning strikes or the operating overvoltage exceeds the rated voltage of the arrester,...

Claims

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Application Information

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IPC IPC(8): G06K9/00G01R19/15G01R31/00
CPCG01R19/15G01R31/00G06F2218/06G06F2218/12
Inventor 束洪春浦通曹璞璘张瑀明张瑞颖
Owner KUNMING UNIV OF SCI & TECH
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