A PRACTICAL CONCEPT FOR EVALUATING THE INSULATION LEVEL IN OVERHEAD POWER TRANSMISSION-LINES

This paper presents a way to determine the maximum voltage distributio n along practical power transmission lines for various switching cases of operation, where the earth effect is considered. The switching ove r-voltages at the receiving end of a single circuit non-transposed tra nsmission line are calculated. An analysis concerning the transformati on matrices of both transposed and non-transposed (single and double c ircuit) transmission lines (per Fig. 1) and their physical meaning are illustrated. The insulation level of such power lines is investigated .