The Research On Single-Phase Grounding Fault Selection And Detection Of Small Current Grounding System Based On D-S Evidence Theory

Low voltage distribution network in China is mainly isolated neutral or coil grounding, that is, a small current neutral grounding system. Small current grounding system of single-phase ground fault occurs higher, accounting for more than 85% of all failures. As the weak fault signal is difficult to detect, the single-phase ground fault detection and location of small current neural grounding system has been a major problem of distribution protection.This paper detailed analyzed the temporary steady-state information features of single phase grounding fault of the small current neutral grounding system, with in-depth discussion of existing fault detection and location method to analyze their respective advantages and disadvantages. On the basis of this, by introducing the information fusion technology and D-S evidence theory, this paper proposed an integrated multi-criteria multi-period continuous line selection method aiming at the single grounding fault of small current neural grounding system. Meanwhile, by introducing pattern recognition and wavelet transform technology, this paper implemented fault distance calculation and fault branch determination based on C-traveling Wave.PSCAD/EMTDC simulation results show that the line selection and location scheme proposed in this paper has a good reliability and sensitivity. Finally, this paper completed the design of single phase grounding fault line selection and location device, including hardware, software and anti-jamming design.