A single-phase disconnection fault protection method for distribution network considering the influence of neutral point grounding mode

A neutral point grounding and disconnection fault technology, applied in emergency protection circuit devices, electrical components, continuity testing, etc., can solve problems such as low reliability and small application range, and achieve improved applicability, sensitivity, and ease of use. effect achieved

Active Publication Date: 2020-09-25
GUIZHOU POWER GRID CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] Therefore, the technical problem to be solved by the present invention is that the single-phase disconnection fault identification method of the distribution network in the prior art has low reliability and small application range, etc.

Method used

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  • A single-phase disconnection fault protection method for distribution network considering the influence of neutral point grounding mode
  • A single-phase disconnection fault protection method for distribution network considering the influence of neutral point grounding mode
  • A single-phase disconnection fault protection method for distribution network considering the influence of neutral point grounding mode

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Embodiment

[0061] refer to Figure 1~2 , this embodiment provides a single-phase disconnection fault protection method of a distribution network considering the influence of the neutral point grounding mode, figure 1 There are 6 feeders in the is the three-phase induced electromotive force of the transformer, is the three-phase current flowing into the bus from the upper grid, is the neutral point voltage, the neutral point grounding resistance R d 10Ω, arc suppression coil inductance L p The degree of overcompensation is 10%. Considering the asymmetry of the line-to-ground capacitance, the parameters are shown in Table 1.

[0062] Table 1 Line parameters

[0063]

[0064]

[0065] The present invention includes a starting element 100, a short-circuit blocking element 200, a line selection element 300 and a signal element 400. The starting element 100 is an element composed of a plurality of logic modules and has a function of judging whether the protection is started. The...

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Abstract

The invention discloses a single-phase disconnection fault protection method considering the influence of a neutral point grounding mode for a power distribution network. The method comprises a starting element, a short circuit locking element, a line selection element and a signal element. The method comprises the following steps of calculating a normal operation neutral point unbalanced voltageUunb and a disconnection fault neutral point voltage change maximum value UOmax according to the system parameters and the grounding mode; measuring a neutral point voltage UO, and judging whether a starting element acts or not; calculating bus phase current variation to judge whether the short-circuit locking element acts or not; calculating the amplitude variation ratio of the positive sequencecurrent to the negative sequence current of the feeder line, and judging a faulty feeder line by a line selection element; and enabling the signal element to send an alarm or tripping signal. According to the invention, the problems of low reliability and small application range of the existing broken line protection are solved, the neutral point grounding mode, the fault position and the influence on the ground capacitance are considered, and the sensitivity and the reliability are higher.

Description

technical field [0001] The invention relates to the field of electric power system relay protection, in particular to a single-phase disconnection fault protection method of a distribution network considering the influence of a neutral point grounding mode. Background technique [0002] With the rapid economic development and the increasing demand for electricity, the scale of distribution network is growing day by day, and the safe and reliable operation of distribution network directly affects the quality of electricity consumption of users. In recent years, due to the complex structure of the distribution network, the alternation of old and new lines, and the influence of natural disasters, external mechanical forces, electrical effects and other factors, the frequency of disconnection faults has shown an upward trend. Disconnection faults lead to asymmetrical three-phase voltage and current on the power supply side and load side, and the appearance of negative sequence a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26G01R31/54G01R31/52G01R19/165
CPCG01R19/16538G01R19/16576H02H7/26
Inventor 杜雪王钟玉黄亮程黄明付滨肖扬欧阳金鑫刘兵刘骁杨杨忠李华鹏龙航张盛安刘俊鑫王承政盛兴隆廖燕黄杰东熊小伏龙晓轩
Owner GUIZHOU POWER GRID CO LTD
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