A line selection method for single-phase ground fault in small current grounding system based on fastica

Abstract

The invention relates to the technical field of grounding fault identification, in particular to a line selection method based on a FastICA for a low current grounding system in a single-phase grounding fault. According to the method, the FastICA method is utilized to process zero-sequence current of the grounding fault, three observation channels are arranged to separate fault steady-state components, transient-state components and noise signals from observation signals, the line fault characteristics are obvious after processing, and accurate line selection can be conducted on a fault line according to the energy of line separation variables. Because the noise signals are separated at the same time, the method is reliable, high in anti-interference capability and capable of not being affected by interference signals; meanwhile, for different initial phase angles of the fault, satisfactory line selection results can all be obtained by means of the method. By using the method to decompose and analyze the zero-sequence current of the fault, the cancellation or compensation among the components of the signals can be avoided, so that the fault characteristics are obvious to achieve the accurate line selection, and the method is widely applicable to the low current grounding system.

Description

technical field [0001] The invention relates to the technical field of ground fault identification, in particular to a line selection method for a single-phase ground fault of a small current ground system based on FastICA. Background technique [0002] For low-current grounding, arc-suppression coil grounding, and high-resistance grounding systems where the neutral point is not grounded, the uncertainty of the single-phase grounding arc makes arc modeling difficult, and the small grounding current and complex interference signals seriously affect the line selection. Accuracy. At present, the methods to solve this problem include the ratio-amplitude-phase method, the fifth harmonic method, the zero-sequence admittance method, the power method, the first half-wave method, the energy method, the spectral power method, the wavelet method, and the injected signal method. The effect of the method application is not ideal. The traditional amplitude method and direction method ar...

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Problems solved by technology

[0002] For low-current grounding, arc-suppression coil grounding, and high-resistance grounding systems where the neutral point is not grounded, the uncertainty of the single-phase grounding arc makes arc modeling difficult, and the small grounding current and complex interference signals seriously affect the line selection. Accuracy

At present, the methods to solve this problem include the ratio-amplitude-phase method, the fifth harmonic method, the zero-sequence admittance method, the power method, the first half-wave method, the energy method, the spectral power method, the wavelet method, and the injected signal method. The effect of the method application is not ideal

The traditional amplitude method and direction method are affected by intermittent arc faults, and are not suitable for the neutral point through the arc suppression coil grounding system

Harmonic method and active component method are difficult to obtain satisfactory line selection results because the corresponding component content is too small

Line selection methods based on modern signal processing technology (such as wavelet transform method), although wavelet analysis is very sensitive to singular points, and the line selection results are easily affected by interference signals

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