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A fast line selection method for single-phase grounding fault in small current grounding system

A single-phase ground fault and small current grounding technology, applied in the field of power systems, can solve the problems of small 5th harmonics, difficulty in selecting wavelet bases, difficulty in proposing, etc., low requirements for achievement, low storage space requirements, and improved correct line selection sexual effect

Active Publication Date: 2022-05-10
HUANGGANG POWER SUPPLY COMPANY HUBEI ELECTRIC POWER
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

By comparing the 5th harmonic current of the faulty line and the non-faulty line, the 5th harmonic method is proposed, but the 5th harmonic is very small, and it is difficult to propose
The wavelet method analyzes the transient zero-sequence current signal through the wavelet transform theory, and can perform fault line selection, but it is very difficult to select a suitable wavelet base

Method used

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  • A fast line selection method for single-phase grounding fault in small current grounding system
  • A fast line selection method for single-phase grounding fault in small current grounding system
  • A fast line selection method for single-phase grounding fault in small current grounding system

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Embodiment Construction

[0028] The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

[0029] Such as figure 2 The simulation model diagram of a 110kV / 10.5kV small current grounding system is shown, S is the 110kV power supply, and the 10kV bus has four 10kV feeders, each with a certain load. That is, not grounded or grounded through the arc suppression coil. Line 1 is a cable line, Line 2 is an overhead line, Line 3 is an overhead line, and Line 4 is a cable line.

[0030] The fault point is set at f on line 1 which is 1km away from the 10kV bus, and the fault time is 0.102s respectively. In order to verify that the method of the present invention is basically not affected by line length, transition resistance, and arc suppression coil, the following five situations are set:

[0031] Case 1: The length of line 1 is 3km, the length of line 2 is 15km, the length of line 3 is 1km, the length of line 4 is 2km, the transition re...

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Abstract

The invention discloses a fast line selection method for a single-phase grounding fault in a small current grounding system. First, the instantaneous value of the three-phase current at the outlet of each feeder line in the substation is collected in real time; secondly, according to the instantaneous value of the current, the instantaneous value of the zero-sequence current of the line is calculated, and the second-order derivative of the instantaneous value of each zero-sequence current is obtained by interpolation method; then, Taking the fault occurrence time as the zero time, find out the maximum value and minimum point of the second order derivative of the zero-sequence current instantaneous value of each line within 3ms; finally, find out the characteristic quantity of the zero-sequence current change trend of each line, and find out the maximum characteristic quantity , that is, it is judged that the line is a faulty line. The method of the invention is less affected by line length, transition resistance and arc suppressing coil, and can quickly select a single-phase grounding fault line.

Description

technical field [0001] The invention belongs to the field of power systems, and relates to a line selection technology for a single-phase ground fault in a distribution network, in particular to a fast line selection method for a single-phase ground fault in a small current grounding system. Background technique [0002] my country's 10kV distribution network system generally adopts the neutral point indirect grounding method, including neutral point non-grounding, arc suppression coil grounding, and resistor grounding. In the neutral point indirect grounding system, when a single-phase grounding fault occurs, the current at the fault point is very small, so it is also called a small current grounding system. When a single-phase ground fault occurs, the neutral point voltage rises from zero to the phase voltage, and the line voltage between the three phases remains symmetrical, which does not affect the normal power supply. Therefore, the system is generally allowed to conti...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/08G01R31/52G01R31/60
CPCG01R31/086G01R31/088G01R31/52G01R31/60
Inventor 胡秀明张春芬叶傲辉程栋江锋唐亚夫詹清铁宋翔林
Owner HUANGGANG POWER SUPPLY COMPANY HUBEI ELECTRIC POWER
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