Wavelet analysis in transient based protection for power system high voltage transmission line

Transient Based Protection using the transient information of fault generated current signals of high voltage transmission line is a new direction of power system protection. According to the attenuation effects of high voltage transmission line and busbar capacitance to high-frequency current transients, differences of current transients at each end of the transmission line when in-zone faulted and out-zone faulted are analyzed and used to deduce the Transient Current Content Ratio (TCCR). Transient Based Protection criterion using TCCR is proposed, and the principles of protection settings are given. Wavelet modulus maxima of current transients are used to calculate TCCR. EMTP simulations of different faults using a 100kHz sample rate are carried out for testing and analyzing the protection criterion. The protection criterion is proved simple, reliable and whole-line protective.