Practical experiences and technical challenges in large scale introduction of on-line PD diagnosis for power cables

On-line partial discharge detection and location equipment for medium voltage cables have become available recently. Efficient implementation can be realised by monitoring cable connections containing several cable sections with ring main units or even a complete substation in between. This paper discusses the consequences related to diagnoses of complex cable connections by a single partial discharge detection system. The feasibility of monitoring several power cable sections at once is illustrated with a practical example obtained with recently installed systems in the Dutch grid. It is shown that detection and location of partial discharges is indeed possible for signals travelling over long connections including ring main units.