Low-current grounding power grid single-phase intermittent arc grounding fault positioning method

A technology of small current grounding and arc grounding, which is applied to the fault location, detects faults according to the type of conductor, and measures electricity. It can solve problems such as failure of fault location and injection of disturbance signals into fault lines, and achieve the effect of avoiding arc reignition

Active Publication Date: 2019-11-29
STATE GRID LIAONING ELECTRIC POWER RES INST +3
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Problems solved by technology

In the case of single-phase intermittent arc grounding, if the moment of the parallel resistance is the gap where the arc is temporarily extinguished, the disturbance signal cannot be injected into the fault line, and the fault location will fail

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  • Low-current grounding power grid single-phase intermittent arc grounding fault positioning method
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  • Low-current grounding power grid single-phase intermittent arc grounding fault positioning method

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Embodiment Construction

[0023] The present invention will be further described in detail through the accompanying drawings and specific embodiments below.

[0024] Such as figure 1 As shown, the present invention provides a method for locating a single-phase intermittent arc ground fault in a small current grounded power grid. After determining the fault phase, use the DB6 wavelet to decompose the bus voltage of the fault phase, and select the scale of wavelet decomposition according to the actual sampling frequency, and record the number of mutations of the fault phase voltage N within the Δt time interval; when N is less than the set value Nset, directly inject the disturbance signal ; When N is greater than the set value Nset, it is judged as intermittent arc grounding, and the re-ignition moment of the intermittent arc is captured by the fault phase voltage characteristics, and the disturbance signal is injected at the next sudden change of the fault phase bus voltage, and the fault phase current...

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Abstract

The invention discloses a low-current grounding power grid single-phase intermittent arc grounding fault positioning method. According to the method, an arc combustion state is detected; an arc reignition moment is captured; disturbance signals are injected immediately in the initial stage of arc reignition; an intermittent arc is converted into a stable arc; and therefore, a fault line and a non-fault line can be distinguished through the indication condition of a fault indicator when disturbance signals are injected successfully in a fault phase, and meanwhile, a fault area is determined. Compared with random disturbance signal injection, the method can assist in avoiding the invalidity of disturbance signal injection during arc extinguishing, avoiding arc reignition caused by fault phase voltage rise due to the disturbance signal injection during the arc extinguishing, and does not additionally increase the overvoltage burden of a system. The disturbance signals are injected in an electric arc combustion period; the increase of fault current is beneficial to promoting the conversion of the intermittent electric arc to the stable electric arc; and therefore, the hazards of the intermittent electric arc are reduced, and meanwhile, the effectiveness of fault positioning is improved.

Description

technical field [0001] The invention relates to the technical field of power fault detection, in particular to a method for locating a single-phase intermittent arc grounding fault in a small current grounding power grid. Background technique [0002] my country's 6-35kV medium-voltage distribution network mostly adopts the non-effective neutral point grounding method. Among the faults that occur during system operation, single-phase grounding faults have the highest proportion. Due to the complex structure of the distribution network and the small fault current generated by the single-phase-to-ground fault, it is difficult to locate the fault. At present, many theoretical methods have been proposed for fault location in the case of single-phase grounding in distribution network, and many devices have been put into field operation. [0003] Currently proposed fault location methods mainly include fault signal location and injection signal location. When a single-phase inte...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
CPCG01R31/086G01R31/088Y04S10/52
Inventor 聂宇张新宇赵丹王雅楠赵传宗杜威王诗清刘垣彤赵孟臣姜君赵凤琦王彦静刘文祥
Owner STATE GRID LIAONING ELECTRIC POWER RES INST
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