An Approach for Accurate Modelling of Frequency Dependent Effects of a Double Circuit DC Transmission Line on Common Tower

Abstract

This paper presents modified approximation techniques in modal frame for frequency dependent effects of a double circuit DC transmission line on common tower.
Elements of transformation matrix and surge admittance are approximated with not only first but also second order transfer function. Also unstable terms are introduced. Addition of second order and unstable terms reduces approximation error. The transient calculation of the Bergeron type model with unstable terms was numerically stable.
Also the paper describes a new smoothig method based on eigen vector tracing technique for frequency dependent effects.