| It is troublesome when it comes to a single phase fault happened on a non-direct-ground system, a host of scholars have dwelt on it. Actually, most of these works are based on steady conditions. Owing to the low value of the steady currents, these works cannot match needs. Hence, this paper provides a new idea based on the analysis of transient arguments and arisen form wavelet analysis.The last half-century has seen the great crystallization, wavelet within harmonic analysis taken place. As a new type of time-frequency analysis media, it excels in its good localization character both in time domain and in frequency domain comparing with traditional Fourier analysis. It changes its sampling steps to smaller and smaller so as to analyze high frequency part, focusing on any part of the object been analyzed.To some extent, Wavelet Analysis is called "Math Microscope". This paper adopts Wavelet Analysis to solve fault circuit selection of non-direct-ground system, which attributes to the steady run of power system.When a single phase fault happened, the fault current is too low to affect the symmetry of a given power system. According to the regulations, it is admissible to run with fault for 1 hour or 2. But it is quite meaningful to find out where the fault is and rule it out quickly and accurately.This paper provides a principle based on wavelet analysis and ANN to settle faultlocation, supposing that the simulations on fault circuit selection is successful.It is well known that ANN is a kind of information processing system, utilizing physical realizable equipment to simulate the structure and function of a neuron. Not only is ANN a large scope and parallel nonlinear dynamics system, but also it has several advantages such as distributed information storage, parallel processing and self-learning. This paper adopts wavelet analysis and BP network to simulate the fault location, and the success proves the feasibility of this idea.
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