1. This chapter established the simulation model for small current grounding system which used the arc suppression coil to grounding through the Simulink toolbox in MATLAB and used the actual parameters as the simulation data. The simulation reproduced the physical changes of the system's zero-sequence current and voltage in the fault time. The offline simulation in MATLAB also reflected the full influence which circuit's structure, parameter's changes, and transition resistance's changes acted on the physical quantity of fault system. 2. This chapter made wavelet packet's decomposition for the transient component of zero sequence by wavelet analysis and accurately obtained the abundant fault information of transient component which contained the signals of single-phase ground fault in small current grounding system. This chapter proposed a new line selection's algorithm based on modulus maxima of the first wavelet packet, namely one-dimensional multi-scale wavelet decomposition is made for zero-sequence current of each feeder by using wavelet, and the fault line is determined by comparing modulus maxima of the feeders in the characteristic scales. The simulation analysis in MATLAB verified the feasibility of this approach.
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