Preparation and Properties of Nano-Cellulose Modified Natural Ester Liquids

Natural ester insulating oil, as dielectric liquid, with high burning point and renewable electrical property, has been widely applied in power distribution transformer. However, the poor heat dissipation of natural ester insulating oil restricts its application in higher voltage level. Nanotechnology is widely used in improving the thermal conductivity and insulation properties of insulating oil. This paper introduced the preparation method of nano-cellulose (CNF) modified natural ester insulating oil, insulating oils with different concentrations of nano-cellulose were prepared and influence of nano-cellulose on electrical and thermal performance were investigated. The result shows that low proportion of nanodoping can effectly increase breakdown voltage, relative dielectric constant rise slightly after doping, electrical conductivity of nano insulating oil decreases as the doping concentration increases and the dielectric loss factors of natural ester insulating oil increases slightly after doping. The thermal conductivity test result shows that the doping of nano-cellulose can improve the thermal conductivity of natural ester insulating oil, and as temperature increases the thermal conductivity decrease slightly at 25 °C and 90 °C. The result shows that doping of nano-cellulose can improve both the thermal conductivity and insulation properties of natural ester insulating oil.