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Distribution grid fault starting method based on fault moment S-transform spectrum characteristic

A technology of distribution network fault and spectrum characteristics, applied in the direction of fault location, etc., can solve the problem of low reliability and high

Active Publication Date: 2015-05-20
CHUXIONG POWER SUPPLY BUREAU OF YUNNAN POWER GRID CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to propose a distribution network fault start-up method based on the S-transform spectrum characteristics at fault time to solve the problem of low reliability in the existing distribution network fault start-up method

Method used

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  • Distribution grid fault starting method based on fault moment S-transform spectrum characteristic
  • Distribution grid fault starting method based on fault moment S-transform spectrum characteristic
  • Distribution grid fault starting method based on fault moment S-transform spectrum characteristic

Examples

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Effect test

Embodiment 1

[0046] Embodiment 1: A flow chart of a distribution network fault startup method based on the S-transform spectrum characteristics at the fault time is as follows: figure 1 shown. At the sampling rate of 1MHZ, collect the zero-sequence voltage time domain waveform within the 16ms time window, such as figure 2As shown, perform S-transformation on it, and then calculate the modules of the elements of the obtained S-matrix to obtain the S-module matrix, and extract the amplitude-frequency characteristics of the S-module matrix at the moment of sudden change, as shown in image 3 shown. Finally, the variance ξ=1.0178 of the amplitude-frequency characteristic at this moment is calculated.

[0047] Set the variance threshold of the amplitude-frequency characteristic of the zero-sequence voltage S-mode matrix Because ξ=1.0178>0.1, it is determined that a single-phase fault occurs in the distribution network, and the line selection device is activated.

Embodiment 2

[0048] Embodiment 2: A flow chart of a distribution network fault startup method based on the S-transform spectrum characteristics at the fault moment is as follows: figure 1 shown. At the sampling rate of 1MHZ, collect the zero-sequence voltage time domain waveform within the 16ms time window, such as Figure 4 As shown, perform S-transformation on it, and then calculate the modules of the elements of the obtained S-matrix to obtain the S-module matrix, and extract the amplitude-frequency characteristics of the S-module matrix at the moment of sudden change, as shown in Figure 5 shown. Finally, the variance ξ=0.0154 of the amplitude-frequency characteristic at this moment is calculated.

[0049] Set the variance threshold of the amplitude-frequency characteristic of the zero-sequence voltage S-mode matrix Because ξ=0.0154<0.1, it is judged that there is no fault in the distribution network, and the line selection device does not start.

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Abstract

The invention provides a distribution grid fault starting method based on a fault moment S-transform spectrum characteristic and belongs to the technical field of electric system relay protection. The method comprises the following steps of acquiring a zero sequence voltage time domain waveform in a short time window at a sampling rate of 1MHz, and performing S transformation on the zero sequence voltage time domain waveform to obtain a zero sequence voltage S matrix; then calculating an absolute value of each element of the S matrix so as to obtain an S modular matrix, and extracting the amplitude-frequency characteristic of the S modular matrix at mutagenesis moment; and finally calculating the variance zeta of the amplitude-frequency characteristic at the moment, if the variance zeta obtained by calculation is greater than a set threshold, judging that a distribution grid has a single-phase fault and starting a route selection device, otherwise judging that no fault occurs, and ensuring that the route selection device is not started. Verification of theoretical analysis and measured data indicates that the method is favorable in effect.

Description

technical field [0001] The invention relates to a fault starting method for a distribution network based on S-transform spectrum characteristics at fault time, and belongs to the technical field of power system relay protection. Background technique [0002] The distribution network in my country widely adopts the low-current grounding method. This grounding method can still ensure the symmetry of the line voltage when a single-phase grounding fault occurs, and does not affect the continuous power supply to the load. However, after the single-phase grounding fault occurs, due to the weak fault current and the unstable arc, the reliable starting of the single-phase grounding fault has not been well solved for a long time. [0003] The method based on the power frequency components of the zero-sequence voltage and current has low sensitivity and is affected by the arc suppression coil; although the method based on the 5th or more harmonics of the zero-sequence signal is not af...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
Inventor 黄兴仓李绍荣马庆龙段军鹏李起荣朱净松张航陈继金张宇韬蒋陈根张曦源杨以波束洪春余多白冰
Owner CHUXIONG POWER SUPPLY BUREAU OF YUNNAN POWER GRID CO LTD