An Evaluation of Impulse Characteristics by Water Tree Growth in XLPE Cables

Abstract

The relationship of AC breakdown performance and water tree has been reported. This time, using aged XLPE cables with some protrusion on the outer semiconductor layer, we evaluated the relationship of water tree growth and impulse breakdown performance. As a result, in case of XLPE cables without waterproof layer, it was confirmed that the impulse breakdown performance decreased because of water tree, and we got possibility the impulse breakdown performance depended on the progress of water tree growth. In addition, it might decrease to the around LIWV. On the other hand, in case of XLPE cables with waterproof layer, though water tree progressed slowly, the impulse breakdown performance was maintained for a long time. In other words, the effect of waterproof was proved. Even if XLPE cables with waterproof layer have big protrusion, most of water tree started from the protrusion does not grow up. But, if water tree grows up, it may largely reduce the impulse breakdown performance of XLPE cables with waterproof layer.