What choices are there available in the detailed design of MV cables?

In the early 1980´s, extruded semiconducting insulation screens for XLPE cable cores made a substantial difference to the performance of MV power cables operating in the presence of moisture. This was followed by improvements in screen smoothness and lower ionic contamination and also by reduced contamination in insulation materials. In addition, tree retardant XLPE compounds also became available. The alternative filled EPR insulation compounds have been available too; changes in polymer crystallinity have resulted in further compounds that have given very good results in Europe, although compound variability has to be tackled and, in Spain, UNIPEDE failure statistics have indicated a less satisfactory picture. Confidence will increase further as experience with triple extruded cables accumulates and as the UNIPEDE long terms tests for water treeing, or equivalent test regimes, point to the right technologies. Here, the author puts forward polymeric cable designs that take account of the above factors in the hope that these will generate critical discussion