Evaluation of materials for WTR-insulated power cables

In order to improve the resistance to water treeing of standard crosslinked polyethylene (XLPE) insulation used in medium voltage power cables, a numb er of materials were selected and studied that represent different water tr ee growth prevention strategies: (a) using materials with crystallinity and morphology different from that of XLPE, or (b) using additives modifying t he interaction between water and materials. Two laboratory procedures were adopted that assess the water tree resistance performance of the materials through different criteria: one based on divergent field geometry (CNRS) an d another based on uniform field geometry (Pirelli). Both tests are shown t o be complementary in their prediction of the performance of the selected w ater tree resistant materials. The work reveals a specific additive that gr eatly increases the water tree resistance performance of the insulation in different polymeric matrices.