Maximum Lightning Overvoltage Along a Cable Protected by Surge Arresters

This paper presents a procedure for calculating the maximum lightning overvoltage along a cable which is protected by arresters at both ends. It is shown that the most severe cable overvoltages that can occur (close back-flashover) will appear at a distance from the remote cable end which is in the order of some hundred meters. The maximum voltage is calculated by adding the peak value of the voltage wave in the forward direction and the peak value of the voltage wave in the backward direction. The location of the maximum voltage is obtained by considering the difference in time instants at which the peak value occurs at the remote end. This procedure only requires to calculate the voltage at the cable ends and the surge arrester current. The forward and backward waves can then be calculated by simple expressions. The procedure is demonstrated for a 300 kV system, for different cable lengths.