The effect of temperature on the electrical breakdown voltage of XLPE in the presence of water trees

This paper discusses the effects of temperature on the electrical breakdown voltage when water trees are present, as well as the characteristics of XLPE containing only microvoids filled with water. Research indicates that there are two regions in which the effects of temperature may be seen in the presence of water trees, one being the range from 20 °C to 60 °C, and the other from 60 °C to 90 °C. In the lower range, the breakdown voltage remains nearly constant at any range, but the value itself is relatively low compared with the breakdown voltage of XLPE which contains only microvoids. In the higher range, 60 °C – 90 °C, the breakdown voltage increases as temperature rises. This is interesting in view of the fact that the breakdown stress in the original XLPE decreases as temperature increases.