Calculation of transmission line transients using polar decomposition

The paper presents a new power transmission line model suitable for the calculation of electromagnetic transients on overhead lines and underground cables. This is achieved by expanding the fitted modes of a conventional line model with constant transformation matrices into simple fractions on the diagonal, and by extending the transformation matrices into rectangular matrices. The new transformation matrices are then refined by a simple iteration procedure based on least squares fitting in the phase domain. The method is demonstrated to give accurate simulation results for both overhead lines and underground cables.