Power Single-phase Earth Fault Line Selection Method By The Improved HHT

3-66 kV power system in our country mainly adopts the small current grounding way(via arc suppression coil grounding or neutral point grounding)and its advantage is the power supply reliability.Single phase ground fault account for more than 80% of all faults in the circuit,so can quickly find fault line accurately,to protect the safety of the power grid operation has important practical significance.This paper first introduces the development status quo of single-phase earth fault line selection,single-phase earth fault occurred after steady transient analysis.Then choose the Hilbert huang transform(HHT)-as a routing algorithm in this paper,HHT can adaptive to fault signal decomposition,traditional HHT using empirical mode decomposition(EMD)method,the decomposition of the intrinsic mode function(IMF)component has the defects of modal aliasing,and collection of empirical mode decomposition(EEMD)method to improve.Failure model is established by Matlab simulation software,the improved HHT is used to determine the fault began to moment,and the three different fault types,fault distance,Angle of the fault and grounding resistance)of the information entropy curve,draw a grounding resistance’s influence on the information entropy is the largest.Finally the fault measure and extreme learning machine(ELM),from the correlation coefficient method and the transient energy method to select the best line selection method,through the simulation results that this method has high accuracy.