Novel single-phase earth fault starting method

A single-phase ground fault, a new type of technology, applied in the direction of detecting faults, fault locations, measuring devices, etc. according to the conductor type, can solve the problems of arc difficult to extinguish, increase of grid capacitance, influence of normal operation of power system, etc., to improve sensitivity , the effect of reducing noise, reducing computational burden and application difficulty

Active Publication Date: 2019-07-12
FUZHOU UNIV
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Problems solved by technology

With the expansion of the scale of the power grid, especially the increase in the use of cables and the increase in line distance, the capacitance of the power grid to the ground increases. Once a ground fault occurs, the resulting arc is difficult to extinguish, which will seriously affect the normal operation of the power system. influences

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  • Novel single-phase earth fault starting method
  • Novel single-phase earth fault starting method
  • Novel single-phase earth fault starting method

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Embodiment Construction

[0040] The technical solution of the present invention will be specifically described below in conjunction with the accompanying drawings.

[0041] This embodiment provides a single-phase-to-ground fault starting method, such as figure 1 shown, including the following steps:

[0042] Step S1: Perform Mallat wavelet packet decomposition on the zero-sequence voltage signal collected in real time to obtain specific frequency band components of the zero-sequence voltage signal, and on this basis, calculate the periodic variation of the selected high and low frequency components; this step specifically includes the following step:

[0043] According to the zero-sequence voltage data collected in real time, it is decomposed by Mallat wavelet packet. The recursive formula of Mallat algorithm is shown in formula (1) and formula (2):

[0044]

[0045] (p is an even number, j>0)

[0046]

[0047] (p is an odd number, j>0)

[0048] Among them, S j and W j is the approximate c...

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Abstract

The invention relates to a novel single-phase earth fault starting method. The method comprises the steps of carrying out wavelet packet transformation on a zero sequence voltage signal of a bus to obtain a specific frequency band component; further processing the history data of a high-frequency component and a low-frequency component to obtain a self-adaptive threshold value for diagnosing whether a system is disturbed or not; and rapidly detecting the single-phase earth faults according to whether the system is disturbed or not and the disturbance continuing time. The method is capable of rapidly and correctly recognizing the single-phase earth faults and effectively distinguishing the single-phase earth faults and non-fault behaviors of switching on-load circuits and switching capacitor banks, has relatively strong adaptation capacity and has relatively high recognition correctness under the working condition of noise interference.

Description

technical field [0001] The invention relates to a novel single-phase ground fault starting method. Background technique [0002] The medium and low voltage distribution network usually refers to the power network with a voltage level of 35kV and below, which has a wide distribution range, a complex structure, and is closely connected with users. my country's 6-35kV distribution network generally adopts the low-current grounding method, and the occurrence rate of single-phase grounding faults is the highest under the low-current grounding method, accounting for more than 80% of distribution network faults. With the expansion of the scale of the power grid, especially the increase in the use of cables and the increase in line distance, the capacitance of the power grid to the ground increases. Once a ground fault occurs, the resulting arc is difficult to extinguish, which will seriously affect the normal operation of the power system. influences. Therefore, the research on t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08G01R31/02
CPCG01R31/086G01R31/088G01R31/50
Inventor 郭彩虹郭谋发李紫荆高伟
Owner FUZHOU UNIV
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