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A Method of Distribution Network Fault Line Selection Based on Correlation Analysis of Zero-mode Current Wavelet Coefficients

A technology of wavelet coefficient and zero-mode current, applied in the direction of the fault location, etc., can solve the problems of extended power outage time, line power outage, damaged circuit breaker, etc., to avoid the influence of compensation and overcome the effect of being susceptible to noise interference

Active Publication Date: 2017-02-01
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The method of manually pulling the circuit will also cause instantaneous power failure of the normal power supply line; after automatic reclosing, if the fault cannot be eliminated, the power failure time will be prolonged; the resulting operating overvoltage and resonance overvoltage will cause impact on the power supply network effect, and may damage the circuit breaker or PT

Method used

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  • A Method of Distribution Network Fault Line Selection Based on Correlation Analysis of Zero-mode Current Wavelet Coefficients
  • A Method of Distribution Network Fault Line Selection Based on Correlation Analysis of Zero-mode Current Wavelet Coefficients
  • A Method of Distribution Network Fault Line Selection Based on Correlation Analysis of Zero-mode Current Wavelet Coefficients

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Embodiment 1: as figure 1 As shown in the distribution network structure, set the feeder L 1 An AG fault occurs 5 kilometers away from the beginning, the transition resistance is 20Ω, and the initial phase angle of the fault is 90°.

[0039] (1) The sampling rate is 1MHz, and the wavelet decomposition is carried out by extracting the zero-mode current traveling wave in the 0.2ms short-time window of each line. Here, the db4 wavelet base is used as an example to illustrate, and the high-frequency first-scale wavelet coefficient is selected as the research object ,Such as image 3 shown;

[0040] (2) Calculate the relative polarity of the high-frequency first-scale wavelet coefficients of each feeder line whose total number of lines is 6 according to formula (1);

[0041] (3) Calculate according to formula (2) to form the distribution network fault line selection matrix R.

[0042] R = 1 ...

Embodiment 2

[0044] Embodiment 2: as figure 1 As shown in the distribution network structure, set the feeder L 2 An AG fault occurs 4 kilometers away from the beginning, the transition resistance is 10Ω, and the initial phase angle of the fault is 90°.

[0045] (1) The sampling rate is 1MHz, and the wavelet decomposition is carried out by extracting the zero-mode current traveling wave in the 0.2ms short-time window of each line. Here, the db4 wavelet base is used as an example to illustrate, and the high-frequency first-scale wavelet coefficient is selected as the research object ;

[0046] (2) Calculate the relative polarity of the high-frequency first-scale wavelet coefficients of each feeder line whose total number of lines is 6 according to formula (1);

[0047](3) Calculate according to formula (2) to form the distribution network fault line selection matrix R.

[0048] R = 1 - ...

Embodiment 3

[0050] Embodiment 3: as figure 1 In the distribution network structure shown, set the AG fault on the bus, the transition resistance is 10Ω, and the initial phase angle of the fault is 90°.

[0051] (1) The sampling rate is 1MHz, and the wavelet decomposition is carried out by extracting the zero-mode current traveling wave in the 0.2ms short-time window of each line. Here, the db4 wavelet base is used as an example to illustrate, and the high-frequency first-scale wavelet coefficient is selected as the research object ;

[0052] (2) Calculate the relative polarity of the high-frequency first-scale wavelet coefficients of each feeder line whose total number of lines is 6 according to formula (1);

[0053] (3) Calculate according to formula (2) to form the distribution network fault line selection matrix R.

[0054] R = 1 1 1 1 ...

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Abstract

The invention relates to a distribution network fault line selection method based on correlation analysis of zero modal current wavelet coefficients, and belongs to the technical field of electric power system relay protection. The method comprises, when a single-phase fault occurs in a feeder of a distribution network, extracting recorded zero modal current traveling wave data of each feeder in a narrow window to perform wavelet transformation, and selecting a first-scale wavelet coefficient with high frequency as a research object; working out the relative polarity of the first-scale wavelet coefficient of each line in the narrow window, forming a fault line selection judging matrix R, and thereby determining the faulted feeder according to element in the R. Simulated analysis shows that, when the single-phase fault occurs in the feeder of the distribution network, the faulted feeder can be accurately and reliably determined by using the method.

Description

technical field [0001] The invention relates to a distribution network fault line selection method based on correlation analysis of zero-mode current wavelet coefficients, and belongs to the technical field of electric power system relay protection. Background technique [0002] Single-phase grounding faults frequently occur in small current grounding systems. When a single-phase ground fault occurs, because there is no electrical connection between the earth and the neutral point, the short-circuit current is small, the line configuration protection device will not act immediately, and the reliability of the system operation is improved. Especially if a transient fault occurs, the fault point can quickly extinguish the arc and restore the system insulation, which greatly improves the reliability of power supply to users and significantly reduces the number of power outages. However, when the arc-suppression coil grounding system has a single-phase ground fault, the non-fau...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/08
Inventor 束洪春林丹丹
Owner KUNMING UNIV OF SCI & TECH
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