Insulation Stability and Thermal Conductivity of Transformer Oil Modified by Rare-Earth Composite Nanoparticles
In this work,the mineral transformer oil was modified by CeO2-Al2O3 composite nanoparticles.The insulation and thermal conductivity of the transformer oil modified respectively by CeO2/Al2O3 and pure Al2O3 are compared.It is found that the properties of the modified transformer oil are improved by CeO2 doping.The CeO2/Al2O3 modified transformer oil was optimized,and five kinds of composite nano-particle modified transformer oil with CeO2 mass concentration of 0.3%,0.6%,0.9%,1.2%and 1.5%were prepared.The optimal dispersion concentration of composite nanoparticles was determined to be 0.9%after comparing various performance indexes of the oil products.The breakdown voltage,the moisture content and the dielectric loss factor of the composite nano-modified transformer oil with 0.9%dispersion are 63.9 kV,5.49 mg·L-1 and 0.971%,respectively.The thermal conductivity is 0.132W·(m·K)-1,which is about 17%higher than that of pure oil.