The Small Current Grounding System Research And Implementation Of The Fault Location Based On HHT

Among the country’s low-voltage distribution network, mainly adopt the way ofthe neutral grounding with resistance, neutral grounding by the arc extinction andisolated neutral. especially in6KV~10KV distribution network system， thetransformer neutral is generally not directly grounded. The system can’t make shortcircuit loop, and the grounding fault current is very small when the single phasegrounding occurs, so we called this as the small current grounding system. Recentyears, among the ground fault in the distribution network, the single-phase earth faulthave the high rates of about80%.Single-phase grounding can’t make the tripimmediately in the distribution network, but if long-runing will cause damage to thesystem’s normal operation. So this is particularly important to study the powerdistribution network fault line selection and location.In our country’s low voltage power distribution network, the neutralnon-effectively grounding is one of the most common grounding. When a groundfault occurs, due to the small zero-sequence current on the line, and numerousbranches, make the fault line selection and location has not been solved.This article is on the basis of fault line selection, propose a method based onHilbert transform (HHT) neural network fault location. First, MATLAB simulationmodel is established according to the actual data of the scene, and then by changingthe position of fault point in the circuit, grounding resistance and fault switchingAngle to get a lot of raw data, and deal with the data obtained, to get the zerosequence current of active power, fifth harmonic and the intrinsic mode function(IMF)energy by the empirical mode decomposition (EMD) as three characteristic of faultlocation method, using the neural network method for fault location. At last, it alsouse MATLAB software proves the correctness and reliability of this method.