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Single-phase earth fault line selection method based on transient state high-frequency component correlation analysis

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

Active Publication Date: 2018-10-16
TAIYUAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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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

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  • Single-phase earth fault line selection method based on transient state high-frequency component correlation analysis
  • Single-phase earth fault line selection method based on transient state high-frequency component correlation analysis
  • Single-phase earth fault line selection method based on transient state high-frequency component correlation analysis

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specific Embodiment 1

[0050] For the convenience of description, the specific embodiment 1 of the present invention assumes that the bus has 4 outgoing wires. When a single-phase grounding fault occurs in a power supply system where the neutral point is grounded through the arc suppression coil, the above-mentioned inventive method can be used to realize a perfect single-phase grounding fault line selection. The process of specific embodiment 1 is as follows.

[0051] Attached figure 1 It is a simulation model of a power supply system where the neutral point is grounded through the arc suppression coil, AC Type is 35kV AC power, T0 is a transformer, and the transformation ratio is 35kV / 6kV. It adopts △ / Y connection method, and the neutral point is grounded through the arc suppression coil. The over compensation 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,...

specific Embodiment 2

[0063] Attached figure 1 The neutral point of the arc suppression coil is modified by the simulation model of the power supply system grounded by the arc suppression coil. Only the 6kV high-voltage power supply lines L3 and L4 are retained, and the single-phase grounding fault occurs on the line L4.

[0064] When the instantaneous value of the zero-mode voltage of the busbar u 0 (t)> When setting the value, the single-phase ground fault line selection algorithm starts, and the zero-mode current of 2 power frequency cycles after each feeder fault occurs is recorded i (t), as attached Image 6 , Attached Figure 7 Shown.

[0065] Db10 wavelet is used to decompose the zero-mode current of the two power frequency cycles of each feeder with a 5-layer wavelet packet, remove the lowest frequency band containing steady-state power frequency and transient inductive components, and refactor the wavelet packet decomposition coefficients of each node. Construct and sum up the fault transient h...

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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 single-phase grounding fault line selection method, in particular to a single-phase grounding fault line selection method for a single-phase grounding fault of a neutral point through an arc suppression coil grounding system, and specifically refers to using a db10 wavelet packet to detect each feeder fault The zero-mode currents of two power frequency cycles are decomposed in five layers to extract the transient high frequency components of the fault. The complementary criterion composed of correlation analysis and the sum of high frequency wavelet packet energy is used to realize single-phase ground fault line selection. Background technique [0002] For a long time, the single-phase grounding fault line selection of resonant grounding system has been a problem that has not been effectively solved. After the neutral point adopts the arc suppression coil grounding method, the protection principle based on the power zero sequence d...

Claims

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Application Information

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IPC IPC(8): G01R31/08G01R31/02
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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