Small current grounding system single-phase grounding fault wire selection method based on transient zero-module current

Abstract

The invention discloses a single-phase grounding fault line selection method for a small current grounding system based on transient zero-mode current. Three-phase modeling is performed on the power grid, and different fault conditions are selected for single-phase grounding fault simulation experiments to obtain various lines Transient zero-mode current; extract the above data; perform empirical mode decomposition EMD on the above data; calculate the time-domain energy of multiple IMFs and residual components; add the energy of IMF and residual components to obtain the energy sum of a line , repeat the above steps to obtain the energy sum of all lines; calculate the energy weight coefficients of each line, compare the energy weight coefficients of each line, and the line corresponding to the maximum energy weight coefficient is the faulty line. Comparing the peak value and polarity of the first zero-mode current pulse and the polarity of the first instantaneous power peak value, the zero-mode current amplitude of the faulty line is larger than that of the non-faulty line, and the polarity of the two is opposite. The invention is not affected by arc suppressing coils and fault conditions and can accurately select fault lines.

Description

technical field [0001] The invention relates to a single-phase grounding fault line selection method for a small current grounding system based on transient zero-mode current, and belongs to the technical field of single-phase grounding line selection for distribution networks. Background technique [0002] The neutral point of my country's 6-35kV distribution network widely adopts the small current grounding method, that is, the neutral point is not grounded or grounded through the arc suppression coil. Operation experience shows that the lower the voltage level, the more ground faults, and the most common one is single-phase ground fault, accounting for more than 80%. A single-phase ground fault may cause overvoltage, burn out equipment, or even personal injury or death. Therefore, quickly determining the fault location and troubleshooting is the top priority for improving the reliable and safe operation of the distribution network. [0003] At present, the domestic resea...

AI Technical Summary

Problems solved by technology

The line selection methods based on transient fault information generally include the first half-wave method, line selection using transient reactive power direction, and transient current line selection method based on wavelet transform, etc., but these methods are difficult to obtain and the decomposition effect is not good. and other difficulties

Therefore, it is urgent to analyze the transient signal and extract features from another angle to overcome the difficulties in signal acquisition and wavelet base selection.

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