Transmission Line frequency Impedance Characteristic and It's Influence in Transient Protection

The transient protection with fault generated high frequency transient signals is a developmental direction of modern power system. It has the advantages: quick fault detection, high precision, no influence by the foundation frequency signal, current transformer saturation and fault resistance. Whereas, the protection is still not applied widely in power systems because the theories about the high frequency transient signal transmission and declining are not very clear. In order to improve it, the frequency impedance characteristics of transmission line are analyzed in the paper. And their effects in the transient protection, especially in traveling wave based fault location are presented. Wavelet packet analysis is then introduced to decompose the fault produced transient signals and remove disturbances, and the wavelet packed analysis based transient protection is simulated. The precision of protection and fault location can be improved.