Research Of Single-Phase Arc Grounding Modeling In Neutral Un-effectual Grounding Power Systems

The neutral un-effectual grounded system modes such as non-ground neutral mode,neutral grounding via arc suppression coil mode and neutral grounding via resistance modeare mainly adopted in medium voltage distribution networks in China. This system is thelargest happened single phase ground fault, accounts for about80%of the total failure. Thesingle phase arc grounding fault is a main fault form in medium voltage distribution networks.At present, the single phase ground fault simulation is considered as the metallic groundingfault or grounding fault via a fixed value resistance. Arc grounding is different from themetallic grounding and resistance grounding. It is not linear relationship between the arccurrent and voltage. By using the above-mentioned simulation model, the results can’taccurately reflect the real situation. To create a lab environment to simulate the arc fault isexpensive. Simulated arc fault in an actual power system is not only expensive, and operationis not safe. Therefore, seeking simulation model of arc fault for fault analysis is particularlyimportant.In this paper, four arc models are established. The single phase arc grounding fault andthe model of10kV distribution networks are built based on the MATLAB. Comparing thesimulation waveform with the theoretical waveform and scene recorded waveform, the resultsshow that this model can reflect the characteristics of actual arc grounding fault effectively.By changing the main parameters of the arc models, their characteristic and harmoniccomponents are analyzed, their advantages and disadvantages and the respective scope ofapplication are compared.The arc grounding fault accounted for the majority of single phase ground fault in theneutral un-effectual grounded system. Now there is no effective method to identify arcgrounding fault. This paper extracts the frequency band energy features and local energy features of voltage waveform of fault phase through wavelet transform. The energydistribution features of the various fault signals are analyzed. According to the change of localtime band energy for criterion identify the arc grounding fault with the metallic groundingfault. Through the simulation test, it can effectively distinguish between the arc groundingfault and the metallic grounding fault. The work in this paper laid a foundation of furtherstudy on the single-phase grounding fault in the neutral un-effectual grounded system.