Dutch distribution cable performance

The Dutch distribution network consists of 100% underground cables. The very wet soil and the dense infrastructure were the main reasons for that. The reliability of this network is very high. The total circuit length is more than 90000 km. It consists mainly of paper insulated lead cable, 3-phase belted types. The most commonly used rated voltage is 10 kV. Up till now, the circuit length of XLPE cables is limited, compared to PILC. The early generation of XLPE-cables of the 1970s suffered from water trees. The latest types have tree retardant XLPE insulation and water blocking systems and show good performance. The maintenance of the distribution cable network is guided on a significant scale on the basis of the VLF partial discharge diagnostic mapping method. This method enables the network-owner to focus its maintenance and the replacements on the weak points only. The maintenance costs are reduced considerably, while increasing the reliability of the cable system. This paper starts with a short introduction of the special circumstances in the Netherlands. The network situation is given, with focus on the medium voltage network and the performance of these cable systems. The VLF PD diagnostic method and its results are given.