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Coal mine grid system insulation state monitoring method

A high-voltage power grid, insulation state technology, applied in the direction of measuring electricity, measuring devices, short-circuit testing, etc., can solve the problems of feasibility discount, poor effect, etc., and achieve the effect of low cost, simple online monitoring device, and elimination of stray current

Active Publication Date: 2013-06-05
CHINA UNIV OF MINING & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The various insulation state online monitoring technologies introduced above are mainly aimed at high-voltage power cables of 110kV and above, and the power supply voltage of coal mine power grids is generally 35kV or 10kV. The above-mentioned methods are not effective in practical applications, and the feasibility is greatly reduced. Therefore, it is necessary to conduct further research on online monitoring of coal mine power grid.

Method used

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  • Coal mine grid system insulation state monitoring method
  • Coal mine grid system insulation state monitoring method
  • Coal mine grid system insulation state monitoring method

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Example 1: Artificially select a feeder branch to do a single-phase metal grounding experiment, measure the zero-sequence voltage of the busbar and the zero-sequence current of the non-fault branch, and obtain the zero-sequence impedance of the non-fault branch, that is, the insulation resistance and capacitance to ground, in order to obtain the insulation parameters of all lines, select another branch to do the single-phase grounding experiment or wait for the next non-branch number 1 line to have a single-phase grounding fault, repeat the above experiment, you can get the first The insulation parameters of the faulty line in one experiment, and the insulation parameters of all feeder branches are obtained by combining the results of the two experiments;

[0029] (1) Insulation monitoring is carried out through the online monitoring device, which is realized through the following process:

[0030] A. The change of the instantaneous value of the busbar zero-sequence vol...

specific Embodiment

[0043] (1) The change of the instantaneous value of the busbar zero-sequence voltage transformer is used as a monitoring basis for cable insulation. When the cable insulation performance deteriorates, the system will appear zero-sequence voltage Because the zero-sequence voltage is relatively small, the line selection device will not start, so the possibility of a ground fault in the system can be ruled out, and the degree of insulation degradation can be judged according to the change of the zero-sequence voltage.

[0044] (2) In order to avoid series resonance when the arc suppression coil is in full compensation state, it is necessary to connect an appropriate resistor in parallel with the arc suppression coil, and the damping rate of the power grid will change, so the change of damping rate can be used as another basis for cable insulation monitoring .

[0045] Analysis of the present invention is as follows:

[0046] 1. Single-phase ground fault analysis

[0047] Takin...

Embodiment 2

[0070] Embodiment 2: specific embodiment is as follows:

[0071] (1) When simulating a single-phase metallic ground fault experiment, monitor the zero-sequence voltage transformer of the system and the current transformer of the non-fault branch, start the digital signal acquisition card, and the sampling frequency is 1MHZ, and the zero-sequence voltage and non-fault branch The first five cycle signals of the zero-sequence current of the fault branch are sampled.

[0072] (2) Using fast Fourier transform, in: n is the number of sampling points, and N is the number of sampling points of a power frequency cycle. In this way, the real and imaginary parts of the zero-sequence voltage and each zero-sequence current can be obtained.

[0073] U ( k ) rm = Σ n = 0 ...

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Abstract

The invention provides a coal mine grid system insulation state monitoring method and belongs to an electrical power system feed line insulation state monitoring method. A feed line branch circuit is selected for doing single-phase longitude metal grounding experiment, zero sequence voltage of a bus and zero sequence current of a non-malfunction branch circuit are tested, zero sequence impedance of the non-malfunction branch circuit is obtained, namely, insulation resistance and ground capacitance, for obtaining insulation parameters of all circuits, another branch circuit is reselected to do a single-phase connection low resistance ground experiment or the next circuit with the non-branch-circuit number 1 is waited for generating single-phase ground malfunction, the experiment is repeated, insulation parameters of a first experiment malfunction circuit are obtained, and the insulation parameters of all feed line branch circuits are obtained by synthesizing results of the two experiments. The coal mine grid system insulation state monitoring method has the advantages that insulation degradation degree of the circuits is analyzed from state change of the bus zero sequence voltage and an arc suppression coil, the zero sequence voltage changes to a certain extent, switching-in situations of damping resistance change, and the degradation degree of circuit insulation is forecasted by monitoring change of transient states of a plurality of feature quantities.

Description

technical field [0001] The invention relates to a method for monitoring the insulation state of a power system feeder, in particular to a method for monitoring the insulation state of a high-voltage power grid in a coal mine. Background technique [0002] More than 80% of the accidents in the high-voltage power system are insulation accidents. With the development of power supply and scientific progress, higher requirements are put forward for the reliability and safety of the power supply system. The traditional method of insulation detection in the original power failure test It has been increasingly unable to meet the actual production needs, and it is an inevitable development trend to use insulation on-line monitoring technology for grid insulation diagnosis. In recent years, my country has done a lot of research on cable insulation on-line monitoring, and achieved certain results, but the measurement errors are relatively large. Among the original measurement methods,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/02
CPCG01R31/02G01R27/18G01R31/52
Inventor 梁睿赵国栋周希伦刘建华王崇林庞乐乐高列崔连华付国庆
Owner CHINA UNIV OF MINING & TECH
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