Low-current grounding fault line selection method based on MEEMD decomposition and high-frequency energy

A small-current grounding and high-frequency energy technology, applied in the field of power systems, can solve problems such as the inability to accurately distinguish zero-sequence current frequency bands, and achieve the effects of solving modal aliasing, good applicability, and good robustness

Inactive Publication Date: 2020-04-17
CHINA THREE GORGES UNIV
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Problems solved by technology

[0006] The purpose of the present invention is to solve the technical problem that the prior art cannot accurately distinguish the zero-sequence current frequency band when a single-phase ground fault occurs in a small current grounding system

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  • Low-current grounding fault line selection method based on MEEMD decomposition and high-frequency energy
  • Low-current grounding fault line selection method based on MEEMD decomposition and high-frequency energy
  • Low-current grounding fault line selection method based on MEEMD decomposition and high-frequency energy

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Embodiment Construction

[0061] A method for line selection of small current grounding faults based on MEEMD decomposition and high-frequency energy, which includes the following steps:

[0062] Step 1: Decompose and extract the high-frequency attenuated oscillation component of the zero-sequence current signal, and obtain its energy in the time domain;

[0063] Step 2: Perform line selection by the high-frequency energy ratio of each line and all lines;

[0064] Step 3: Carry out simulation experiments under different fault conditions;

[0065] In step 1, the modified ensemble empirical mode decomposition (MEEMD) with Hausdoff threshold is used to extract the high-frequency attenuated oscillation component of the zero-sequence current signal, and its energy within a certain period of time after the fault occurs.

[0066] In step 1, the zero-sequence current is completely decomposed into power frequency AC components, attenuated DC component frequencies, and high-frequency AC components through the o...

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Abstract

A low-current grounding fault line selection method based on MEEMD decomposition and high-frequency energy comprises the following steps: 1, decomposing and extracting a high-frequency attenuation oscillation component of a zero-sequence current signal, and obtaining energy in a time domain of the zero-sequence current signal; 2, executing line selection according to the high-frequency energy ratio of each line and all the lines; 3, carrying out simulation experiments under different fault conditions. In order to avoid modal aliasing and endpoint effects, reduce sensitivity to noise and solvethe technical problem that zero-sequence current frequency bands cannot be accurately distinguished in the prior art, the invention provides a low-current grounding fault line selection method based on MEEMD decomposition and high-frequency energy.

Description

technical field [0001] The invention belongs to the field of power systems, and in particular relates to a small current grounding fault line selection method based on MEEMD decomposition and high-frequency energy. Background technique [0002] In the prior art, most of the distribution network adopts neutral point not directly grounded. This grounding method helps to improve the reliability of power supply. After a single-phase ground fault occurs, the small current grounding system can still continue to operate for 1-2 hours. However, the requirements for the insulation level of the system equipment are high; if the faulty line cannot be located and eliminated for a long time, it is likely to develop into a serious power supply accident. [0003] The existing fault line selection methods are basically based on the steady-state component and transient component of the zero-sequence current signal. The methods based on the steady-state component include the zero-sequence cur...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
CPCG01R31/086G01R31/088
Inventor 陈炳文李博文曹树立奕仲飞
Owner CHINA THREE GORGES UNIV
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