The cylindrical capacitive model for water treeing degradation in extruded HV cables

摘要

The initiation and growth of voids and microcbannels filled with water and different ions in extruded polymeric insulation of HV cables is usually known in literature as 'water treeing', due to their fan and/or bush-like appearance. Water and electrical trees have revealed as some of the most important causes of cable breakdown detected from late sixties. Since then, many papers have been devoted to study the problem. Nevertheless, although large amounts of experimental results have been provided, there is a lack of physical-mathematical models which explain why those results are produced. In order to propose an adequate and specific model for extruded cables deteriorated by water treeing, we must take into consideration:rna) Internal structure of water trees.rnb) Cylindrical geometry of the device (cable) in which water trees are growing.