Small-current grounding system fault line selection method

Abstract

The invention discloses a fault line selection method for a low-current grounding system, and the method comprises the steps: calculating an analysis signal of a transient zero-sequence current through Hilbert transform, then introducing a frequency shift factor to remove a fundamental frequency component in the transient zero-sequence current, and obtaining a transient non-power-frequency transient component; secondly, calculating normalized transient energy, kurtosis value and cross-correlation distance of fault line selection; and finally, introducing a D-S evidence fusion algorithm to calculate the comprehensive fault measure of each line, judging the line corresponding to the maximum comprehensive measure value as a faulty line, and judging the line corresponding to the non-maximum comprehensive measure value as a non-faulty line. The method for constructing the comprehensive line selection method by comprehensively utilizing various fault transient information for fusion is an effective thought.

Description

technical field [0001] The invention belongs to the technical field of power system fault line selection, and in particular relates to a method for fault line selection of a small current grounding system. Background technique [0002] At present, the problem of fault line selection for small current grounding systems has not been well resolved. When a single-phase ground fault occurs, the transient signal features are abundant, which makes the analysis method based on the transient signal widely concerned. Commonly used transient signal fault analysis methods include: transient energy method, S transform, Prony algorithm , correlation analysis, wavelet decomposition, empirical mode decomposition, etc. [0003] The transient energy method is used for fault line selection. When a large resistance grounding fault occurs, due to the compensation effect of the inductive current of the arc suppression coil on the instantaneous zero-sequence current of the fault, the difference b...

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Problems solved by technology

[0002] At present, the problem of fault line selection for small current grounding systems has not been well resolved

[0005] 1) Due to the limitations of signal processing methods, the extracted fault transient features may have strong uncertainty and randomness, so it is difficult to apply it to all fault conditions, especially for extreme fault conditions, such as high-impedance Fault conditions such as ground fault, fault signal interfered by noise and unbalanced load

[0006] 2) For fault line selection criteria, a single line selection criterion often cannot cover all grounding conditions, and it is difficult to fully adapt to various grid structures and complex fault conditions.

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