Digital monitoring of partial discharges in high voltage cables and switchgear

There is a vast network of aged underground power cables in the UK distribution system. A large majority of these cables, working at voltages up to and including 33 kV, are described as `solid´, being insulated with oil-impregnated paper. They are well known to suffer from damaging internal partial discharge activities. A knowledge of the conditions of these types of power cable would help: (a) determine remaining life; (b) reduce supply interruptions; (c) locate faulty joints; and (d) plan replacement or reinforcement programmes. Here, the author describes suitable techniques for the digital monitoring of partial discharges in high voltage cables and switchgear