الفهرس 
Transformers solid insulationOnly 14 pages are availabe for public view
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Abstract
Oil impregnated paper(OIP)is considered one of the major insulations in power transformers. This study aims to improve the dielectric properties of paper insulation by using nanofluids to ensure the reliability of the paper insulation.Samples which used in the experiments are Kraft paper, mineral oil and three different types of nanoparticles,titanium dioxide(TiO2),aluminum oxide(Al2O3)and silicon dioxide (SiO2) all with particle size of 20 nm. Nanofluid with two different concentrations are prepared,0.01 g/L and 0.02 g/L. The homogenous dispersion of nanoparticles in the fluid is prepared using two-step method. Then, paper samples are impregnated in the prepared nanofluid for 24 hours at 45 °C inside the vacuum oven. Accelerated aging test is performed to simulate the aging conditions in the laboratory by heating Nanooil Impregnated Paper(NIP)and OIP samples at 120 °C in an oven for different periods. Breakdown voltage(BDV)for the fresh nanofluids and NIP samples are measured and compared to that of oil itself. The BDV results are analysed using Weibull distribution analysis. Also, dielectric constant, dielectric loss factor and Dielectric dissipation factor(DDF)have been calculated. Nanoparticles presented significant improvement regarding DDF and dielectric loss factor of the insulation paper. To clarify this enhancement in dielectric properties, physical mechanisms are discussed considering the change in relaxation time after adding nanofillers.