Undercurrent grounding line selection method and device

A technology of small current grounding and line selection method, applied in the fault location and other directions, can solve the problem of low accuracy of low current grounding line selection, and achieve the effect of solving the low reliability and accuracy rate and improving the accuracy rate of line selection.

Active Publication Date: 2019-05-03
STATE GRID CORP OF CHINA +2
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Problems solved by technology

[0004] The purpose of the present invention is to provide a small current grounding line selection

Method used

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  • Undercurrent grounding line selection method and device
  • Undercurrent grounding line selection method and device
  • Undercurrent grounding line selection method and device

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Embodiment Construction

[0034] In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0035] Embodiment of small current grounding line selection method:

[0036] This embodiment provides a method for constructing a logistic regression model. The construction method constructs a logistic regression model (logistic regression model) based on the zero-sequence current active component method, the fifth harmonic method, and the first half-wave method. ground fault line selection, the corresponding flow chart is as follows figure 1 As shown, the specific construction steps are as follows:

[0037] 1) For m lines, collect the active current I when faults occur in N groups kn , the fifth harmonic current I jn and the voltage peak value U in the first half-wave of the transient state hn and peak current I hn , where n=1,2,3.....

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Abstract

The invention relates to an undercurrent grounding line selection method and device. The method is characterized in that when a ground fault of a line is detected, active and reactive components in the fault current are compensated, so the fault current is reduced to a fault current setting threshold; after the setting time, compensation of the active and reactive components in the fault current is stopped, and whether the ground fault disappears is determined; if not, the zero sequence current, the fifth harmonic current and the transient first half wave voltage current peak of each line arecollected, the collected data is preprocessed to obtain a corresponding fault index of each line, the fault index corresponding to each line is inputted into a logistic regression model to determine the fault line, and thereby faulty and non-faulty lines are obtained. The method is advantaged in that the faulty and non-faulty lines can be accurately distinguished, line selection accuracy is substantially improved, and problems of low reliability and accuracy of a traditional single line selection method are effectively solved.

Description

technical field [0001] The invention relates to a small current grounding line selection method and device, belonging to the technical field of power system distribution network. Background technique [0002] In my country, small current grounding is mainly used in 6-66kv medium and low voltage distribution networks, mainly including neutral point not grounding, neutral point grounding through arc suppression coil and neutral point grounding through high resistance. It is difficult to select a small-current grounding line. On the one hand, it is due to the inherent characteristics of the grounding method itself, mainly in the following aspects: weak fault signal, unstable signal caused by arcing, easy to generate arc-light grounding overvoltage and resonance overvoltage, and unable to detect high-resistance faults; On the other hand, it is because the relevant hardware cannot keep up, mainly manifested in: the accuracy of the current transformer is not enough, the setting va...

Claims

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Application Information

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IPC IPC(8): G01R31/08
Inventor 黄利军李献伟周宁冯光张彦龙张敬安谢卫华
Owner STATE GRID CORP OF CHINA
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