Reduced order transmission line modeling for improved efficiency in the calculation of electromagnetic transients

A direct method based on the linear least squares approach is applied for obtaining reduced order approximations of the propagation and characteristic admittance transfer functions of transmission lines for use in calculation of transients. The practical level of the acceptable error is discussed in terms of the precision of the frequency domain input data. The proposed approach provides satisfactory accuracy with a small number of real and/or complex poles. The low order approximation could improve the efficiency of the EMTP by reducing the computation time