Transient sheath overvoltages in armoured power cables

This paper is concerned with methods of limiting the build-up of transient voltages between sheath and armour in long armoured power cables. Calculations by a frequency dependent cable model demonstrate that this voltage can be efficiently limited to an acceptable level by introducing sheath-armour bondings at regular intervals, or by using a semiconductive sheath-armour interlayer. The paper investigates the required minimum length between bondings, as well as the required conductivity of the sheath-armour interlayer if the use of bondings is to be avoided.