Approximating RC distributed circuit in simulating 700 kV potential divider for switching impulse voltage

This paper quantitatively analyses an error in approximating a RC distributed line by discrete elements. It is to be clarified that with a normal RC ladder approximation, error evaluated in the response time does not became negligibly small even when a RC distributed circuit is simulated by as many as 50 small discrete RC elements. In the paper, more efficient approximation, which makes the error small enough to be neglected even using some ten discrete elements only, is to be introduced. The proposed approximation is applied to the unit step response analysis of the potential divider for the switching impulse voltage and its effectiveness is confirmed in comparison to the measured response