Discrimination method of low-current grounding fault of primary and secondary integrated equipment under three-phase asymmetric harmonic power flow calculation

Abstract

In order to realize the accurate judgment of the ground fault and improve the fault discrimination effect, this paper proposes a low-current ground fault discrimination method for the primary and secondary fusion complete sets of equipment under the calculation of three-phase asymmetric harmonic power flow. The three-phase asymmetric harmonic power flow calculation is carried out, the ground fault line selection model is constructed according to the calculation results, and the faulted line is obtained by the zero-sequence active component method and the zero-sequence reactive power component method; the wavelet packet transform method is used to extract the transient zero-sequence power direction, and use it as a line selection criterion to identify whether a ground fault occurs. The amplitude characteristic enhancement value of each section is obtained by calculation. According to the distribution characteristics of the zero-sequence current amplitude of the faulted feeder, the corresponding section is selected as the fault section, and the mutation logic array is used in the determined fault section to realize the low-current grounding fault judgment. The experimental results show that the method has high judgment accuracy in practical application, and the highest value is 98.5 %, which indicates that the method can accurately judge the fault line and determine whether ground fault occurs.

Fault line selection algorithm for single-phase grounding faults in distribution networks based on multi-feature fusion of multi-level wavelet decomposition coefficients

“…A method is presented to isolate single-phase grounding fault lines in distribution networks using an attention mechanism and a convolutional neural network (CNN) [2], although current power grids lack ample fault data for this technique. A method is explored for detecting small current grounding faults in combined primary and secondary devices by analyzing the three-phase unbalanced harmonic tidal flow [3]. It identifies the faulty line through zero-sequence active and reactive component methods and uses the wavelet packet transform method to pinpoint the transient zero-sequence power direction, serving as an indicator of grounding fault occurrence.…”