The Research Of Small Current Grounding Fault Line

Small current grounding power system fault line is a complex problem. Both athome and abroad have long been not very good solve this problem. Method of smallcurrent grounding system, single-phase grounding line selection is very much, from theangle of the signal can be divided into three categories: one line selection is based on thesteady state signal; the two is based on transient signal; the third is based on the first twomethods. Because steady grounding current is weak, unstable arc and other reasons,mistake selection rate is high by using the method of stationary signal, the research focusin recent years has focused on the use of transient signal to construct the line selectionalgorithm. This paper mainly discusses all kinds of time-frequency decompositiontechnique, such as the short time Fourier transform, wavelet transform and the modaldecomposition technique, and how these techniques used for the analysis of transientsignal, which can be connected to the instant signal analysis of characteristics of smallcurrent system, at the same time, according to the characteristics of short-time Fouriertransform, wavelet transform and modal decomposition transform technique, this paperproposes a new wavelet transform conjecture.First, to discuss about the basic line selection principle and method in smallcurrent system at home and abroad; then introduces the short-time Fourier transform,wavelet transform and mode decomposition and time-frequency transform and theircharacteristics in common, and introduces its application in line in the small currentselection system, and puts forward the FIR-wavelet transform method conjecture; finally,this paper introduces the system design of equipment by FPGA(Field-ProgrammableGate Array)、ARM(Advanced RISC Machines)、IPC platform, hardware design and software design, including the analysis of the core part of the circuit design, selection ofmain parts, core software idea and each main part of the software design etc..