Performance characteristics of water blocking tapes and theirinfluence on water treeing in XLPE insulation

摘要

The performance characteristics of several commercially availablewater swellable tapes have been evaluated in terms of their swellingbehavior, water blocking capacity and influence on water treeing inpower cable insulated with cross-linked polyethylene (XLPE). Thenonconducting water blocking tapes have been found to exhibit superiorswelling behavior and water penetration resistance than thesemiconducting tapes, both in single sheet and model cable tests.Accelerated water treeing tests on miniature cables have also shown thatnone of the water blocking tapes had an adverse effect on insulationperformance, in terms of percentage retention of breakdown strength andwater tree growth rate. This evaluation has permitted the screening andselection of water blocking tapes with optimum electrical and waterbarrier characteristics for use in underground distribution cables. Theresults have been confirmed by full-size cable testing