Wavelets Method To Select Single Phase Fault Circuit For Small Current Grounding Power System

When single phase to earth fault occurs on a neutral non-direct grounded power system, it is necessary to select the fault circuit quickly. But, from existing status of this field, it has not been done very well. This paper introduces a novel fault circuit selecting method, which utilizes wavelets transform to obtain useful fault transient components.Firstly, A detailed analysis to fault transient course of these kinds of system is discussed, focusing on the resonance-grounded power system. Furtherly, a fault circuit selecting method based on fault transient components is presented.Secondly, Because wavelet analysis can change the time and frequency windows according to the variation of signals' frequency, it can analyze the singularity of fault signals, and then confirm the accurate fault time efficiently. Then, The fault circuit selecting method utilizing wavelets transform is proposed to obtain useful fault transient components. The results of simulation denote that the methods in this paper are efficient and reliable.Lastly, The influences of arcing grounded are discussed. From the results of simulation, it is found that the fault circuit selecting method proposed in this thesis is applicable to arcing grounded.