Fault Traveling Wave Calculation of T-Connect Transmission System Considering Parameter Frequency Variation

Fault traveling wave calculation is the basis of relay protection and fault location. Because of the skin effect, the line parameters have the characteristic of frequency variation, However, at present, the fault traveling wave calculation for T-connect transmission lines with frequency variation of line parameters is rare. In order to solve this problem, This research develops a method for T-connected transmission systems with frequency-dependent parameters. The process starts with phase-mode transformation to decouple the lines, followed by an analysis of the frequency-dependent characteristics of each modulus parameter, generating the 1-mode traveling wave, which is more stable and applicable for fault analysis. The initial traveling wave is calculated using refraction, reflection, and propagation coefficients. The calculated results show strong agreement with PSCAD/EMTDC simulation results, which shows the accuracy of the proposed method.