Combined phase and modal domain calculation of transmission line transients based on vector fitting

This paper introduces two highly accurate transmission line models. In the first one, particularly suitable for overhead lines, the matrix transfer functions for both characteristic admittance and propagation are fitted directly in the phase domain using the method of vector fitting by optimal scaling. In the second model we use for propagation a modal decomposition with a constant transformation matrix and an optional phase domain correction term. Both models are computationally highly efficient due to their time domain realizations based an vector fitting.