Line Selection Device Based on Double Tree Complex Wavelet

Single phase ground fault has the highest rate to happen in distribution network, use the method based on transient component can improve line selection accuracy effectively. sensitivity and directional selectivity can improved by using dual tree complex wavelet transform than using discrete wavelet translation, there is a decaying current fault line and normal line of difference, the difference is phase to phase delay reflected in current after wavelet transformation , the fault line and normal line zero sequence current and zero sequence current proportion relationship, there still worse a decaying direct current component, the normal phase between the two zero sequence currents are equal, therefore according to the phase relation after wavelet decomposition when will still be able to distinguish the fault line and normal line. Using the fast operation speed of digital signal processor can realized the fault line selection algorithm.