Fault Location for HVDC Transmission Lines Using Interference Cancellation

Currently fault location for HVDC transmission lines demands high sampling frequency and suffers from large fault resistance. In this paper, accurate location at relatively low sampling frequency is obtained with interference cancellation. The CWT (continuous wavelet transformation) is adopted to extract the main component of natural frequencies using the maximum energy entropy of its modulus results. Location interferences are analyzed systematically, and the influences of hybrid wave and harmonic component with fault location are further studied. Interference cancellation is introduced to deal with interferences, mechanism and criteria of cancellation which diminish location errors are built through theoretical analysis and simulation, then a novel fault location method for HVDC transmission lines is proposed. Lots of simulation tests prove its good reliability and accuracy at relatively low sampling frequency.