Investigation of the residual-charge technique for diagnosis of water-tree deteriorated cross-linked polyethylene cable

摘要

Water trees are generated in cross-linked polyethylene (XLPE) cable in the case that it is used under the wet conditions. This water-tree deterioration in XLPE cable is one of the factors that reduce breakdown strength. Therefore, the effectivetechnique has been needed to detect and estimate how much XLPE cable is deteriorated by water-tree generation for retaining the stable power supplies. From these points of view, we have been investigating the application of residual-charge technique to it.We have confirmed so far the effectiveness of residual-charge technique on diagnosis of water-tree deteriorated XLPE cables, and of an application of oscillating wave (OSW) to this technique. An OSW application leads to downsizing of measuring sets infield measurement. Moreover, we proposed a new technique to estimate the degree of water-tree deterioration. This way of estimation could make it possible to detect the existence of the localized and high-degree deteriorated region.