Towards water-resistant high voltage insulation systems: An ageing study of a technological water-blocking polymer

This paper examines the solid state ageing characteristics of a technological water-blocking system, based upon the polysaccharide guar, a material used in lightweight power cable designs as a water tree inhibiting system. Through a combination of viscometry and Raman spectroscopy, we show that ageing primarily affects the polymer backbone, which is not associated with guar/water interactions. We conclude that guar binds strongly with water and that this is not affected significantly by ageing. Guar therefore constitutes an attractive means of protecting high voltage insulation systems from exposure to water, so reducing the likelihood of water treeing, even following many years of ageing.