With the development of power systems and the

extensive application of nonlinear elements in the electricity

system, the problem of ferroresonance do harm to the network

and electricity facilities has become more prominent. Wavelet

analysis has good time-frequency localization characteristic, so it

is suitable for fault analysis of power system. This paper is base

on in the neutral point unearthed system, which is excited by

single phase grounding fault, take analysis of the value of neutral

point with the Daubechies wavelet analysis. Simulation results

show that with wavelet transforms the occurrence of Ferro

resonance time can be detected and the frequency resonance can

also be determined.

-With　the　 development　of　 power　 systems　and　 the

extensive　application　 of　nonlinear　elements　 in　the　electricity

system, the　problem of　ferroresonance　do harm　to the　network

and　electricity　facilities　has　become　more　prominent.　Wavelet

analysis has good time-frequency　localization characteristic, so it

is suitable　for fault analysis of　power system. This　paper is base

on　in the　neutral　point　unearthed　system, which　is　excited　by

single phase grounding fault, take analysis of the value　of neutral

point　with　the Daubechies　wavelet　analysis.　Simulation　results

show　that　 with　wavelet　 transforms　the　occurrence　 of　Ferro

resonance time can　be detected and the frequency resonance　can

also be determined.