Study on Traveling Wave Propagation Characteristics of ±800 UHVDC Transmission Lines

Traveling wave produced by a short-circuit fault or lightning will propagate along transmission lines with deformation and attenuation, which are due to energy loss and frequency-dependent line parameters. By the phase-modal transform method, the multi-conductor transmission lines could be decoupled into independent modal. Each modal is a single uniform line described as two-port networks. In this paper, the frequency-dependent parameters of uniform transmission lines are calculated in complex frequency domain. Based on the telegraph equation in complex frequency domain, the transfer functions between traveling wave signal source and observation point (relay location) are derived. The time domain waveforms of traveling wave at the observation point are calculated by Hosono numerical Laplace inverse transform method. Compared with PSCAD/EMTDC simulation results, the proposed method in this paper is proved effective.