ANALYSIS ON TRANSIENT TRAVELING WAVE AND STUDY ON FAULT LINE SELECTION FOR DISTRIBUTION LINES

Because power frequency fault current is very small in amplitude and the system may operate under an asymmetry condition, it is very difficult to correctly identify the faulted line when single phase to ground fault (SFG) occurs in distribution system with non-effectively grounded (NNG) neutral. After analyzing the characteristics of transient traveling waves resulted from SFG in distribution system with wavelet transform, it is found that the initial transient current traveling waves is irrespective of the neural grounding mode when SFG occurs in this paper. According to fact described above, a new faulted line identification algorithm based on transient traveling waves and wavelet transform is proposed. The simulation result demonstrates that the new algorithm is valid. The algorithm is a new idea and is used to design a new principle of fault line selection for NNG system and it can suit for the every case with different CT.