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Single-phase-to-earth fault line selection method based on correlation analysis of transient high-frequency components

A single-phase-to-ground fault and correlation analysis technology, applied in fault location, fault detection by conductor type, and electrical measurement, etc., can solve problems such as poor reliability and low accuracy

Active Publication Date: 2021-01-01
TAIYUAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the problems of low accuracy and poor reliability of line selection for single-phase ground faults in resonant grounding systems, and propose a line selection method for single-phase ground faults based on correlation analysis of transient high-frequency components. Under the influence of different grounding resistance, initial fault phase angle, arc suppression coil compensation degree, fault location and other factors, the line can be selected correctly, and it is completely suitable for the power supply and distribution system whose neutral point is grounded through the arc suppression coil

Method used

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  • Single-phase-to-earth fault line selection method based on correlation analysis of transient high-frequency components
  • Single-phase-to-earth fault line selection method based on correlation analysis of transient high-frequency components
  • Single-phase-to-earth fault line selection method based on correlation analysis of transient high-frequency components

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specific Embodiment 1

[0051] For the convenience of description, the specific embodiment 1 of the present invention assumes that the busbar has 4 outgoing lines. When a single-phase ground fault occurs in a power supply system whose neutral point is grounded through an arc-suppression coil, the above-mentioned inventive method can be used to realize a perfect single-phase ground fault line selection. The process of the specific embodiment 1 is as follows.

[0052] attached figure 1 It is a simulation model of the power supply system whose neutral point is grounded through the arc suppression coil. AC Type is 35kV AC power supply, T0 is a transformer, and the transformation ratio is 35kV / 6kV. The overcompensation method is adopted, the compensation degree is set to 5%, and the arc suppression coil loss is set to 3%; the transformation ratios of transformers T1, T2, T3, and T4 are 6kV / 0.38kV, 6kV / 0.66kV, 6kV / 1.14kV, 6kV / 3.3kV; the sampling frequency is set to 8kHz, and the line L4 is a single-phase...

specific Embodiment 2

[0065] attached to figure 1 The simulation model of the power supply system whose neutral point is grounded by the arc suppressing coil is modified, only the 6kV high-voltage power supply lines L3 and L4 are reserved, and a single-phase ground fault occurs on the line L4.

[0066] When the instantaneous value of bus zero-mode voltage u 0 When (t)>setting value, the single-phase ground fault line selection algorithm starts, and records the zero-mode current of 2 power frequency cycles after each feeder fault occurs i (t), as attached Figure 6 , attached Figure 7 shown.

[0067] The db10 wavelet is used to decompose the zero-mode current of the two power frequency cycles of each feeder line with 5 layers of wavelet packets, remove the lowest frequency band containing the steady-state power frequency and transient inductive components, and re-decompose the wavelet packet decomposition coefficients of each node The fault transient high-frequency capacitive current componen...

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Abstract

The invention dislcoses a single-phase earth fault line selection method based on transient state high-frequency component correlation analysis. The method comprises the steps that whether or not a single-phase earth fault happens is judged according to the magnitude of a busbar zero-mode voltage instantaneous value, db10 wavelets are adopted for performing five-layer wavelet packet decompositionon zero-mode current of two work frequency periods after each feeder line fault, after the minimum frequency band is removed, node wavelet packet deposition coeffiences are reconstructed and summeredto obtain a fault transient high-frequency capacitance-current component, and a correlation coeefient matrix M between every two feeder lines is obtained; Si is set as a correlation accumulation coefficient for the ith feeder line fault transient high-freuqency capacitance-current component, when rho ij is larger than rho set, Si is equal to 1, 1 is subtracted from Si, and a correlation accumulation coefficient matrix S can be obtained; if Si is larger than 0 constantly, the busbar breaks down; if Si of only one feeder line is smaller than 0, the circuit is a fault circuit; if Si is smaller than 0 constantly, the circuit with the maximum high-frequency-band wavelet packet energy sum is determined as the fault circuit. According to RTDS simulation experimental verification, the method has the good accuracy, adaptability and the like.

Description

technical field [0001] The invention relates to a line selection method for single-phase ground faults, in particular to a line selection method for single-phase ground faults in the neutral point via arc suppression coil grounding system, specifically refers to the use of db10 wavelet packets for each feeder line after the fault occurs The zero-mode current of two power frequency cycles is decomposed into 5 layers to extract the transient high-frequency component of the fault, and the single-phase-to-ground fault line selection is realized by using the complementary criterion composed of correlation analysis and high-frequency wavelet packet energy summation. Background technique [0002] For a long time, line selection for single-phase grounding faults in resonant grounding systems has been an unsolved problem. After the neutral point adopts the arc-suppression coil grounding method, the protection principle based on the zero-sequence directional type of power is no longer ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/08G01R31/52
CPCG01R31/086G01R31/50
Inventor 耿蒲龙曲兵妮罗超郑丽君高云广宋建成田慕琴
Owner TAIYUAN UNIV OF TECH
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