Study on electrical treeing characteristics of nano sio2 modified xlpe insulation material for underground cable applications

Abstract

Underground cable insulating material plays an energetic role in electric power system. Cross linked polyethylene (XLPE) has been used for power cables since the early sixties, because of their outstanding electrical, thermal and mechanical properties. The quality of both the insulation and the semiconducting screen materials has been continuously improved with respect to production processes, contamination level, additives and so on. However, failure of cables due to electrical treeing phenomenon is still considered as a major problem when cables are aged due to both internal and external factors. Electrical treeing starts in the defective (or) weak portion of cable insulation due to enhanced localized electric field stress, which slowly builds up and finally bridges the high voltage conducting core with the ground. Throughout the world, great efforts have therefore been put into the development of new, improved insulation materials, aiming at the ultimate goal of developing an electric tree resistant material. Nano composites are emerging as an innovative insulating material for challenging applications in all types of electrical equipment used in the power systems. The major objective of current research work is to develop innovative solid nano composite material for underground cable insulation. When determining the quality of high voltage cables, the electric lifetime of the cable is an extremely important measure. A prolonged lifetime is closely related to sustainable development, which is a key subject to engineers around the world. As often occurring in high voltage engineering, the insulation thickness of a high voltage cable is a trade-off between reliability and costs. A thicker insulation might be a more reliable option with a longer lifetime, since a lower electric field is present in the material. A reduction of the insulation thickness will reduce the material costs drastically newline