Analysis of Water Treeing Resistance Performance Characteristics of Nano Filled XLPE Cable Insulating Material

Abstract

In recent times, high voltage secondary distribution network in urban areas is widely supported by XLPE cables because of its advantages over conventional overhead lines. Major problem faced in the usage of underground cables is the failure of insulation due to water treeing phenomena. It occurs mainly due to water diffusion in the base XLPE polymeric material leading to the breakdown of cable insulation over a period of time. As a result of water treeing, dielectric strength of the material reduces significantly. Recent advancements in nanotechnology shows that addition of nanofillers in the base polymeric material will enhance the thermal and electrical insulation characteristics of the material. However, very few reports are only available in the literature regarding the water treeing resistance characteristics of nano-modified XLPE material. Hence it is necessary to perform a variety of tests on nano-modified XLPE material in order to collect a large volume of data useful for electrical utilities. Considering these aspects, in this paper, important dielectric performance characteristics of nano SiO2 filled XLPE material such as dielectric constant, tan delta, volume resistivity and capacitance are studied at different %wt concentration of nano-filler. In addition, laboratory experiments were also carried out in order to understand the water treeing resistance characteristics of nano filled XLPE material under virgin and aged conditions.