Fundamental research on the application of nano dielectrics to transformers

Nanotechnologies have potential to be used in transformer industry in enhancing material properties which may lead to a compact design of transformer and reduced manufacturing cost. In this publication, breakdown physics in nanofluids is studied for transformer insulation liquid. Several types of nanoparticles were selected and added into mineral oil. Breakdown voltage, streamer propagation velocity, oxidation stability, permittivity, electrical resistivity and dissipation factor were measured and studied. Results show that the dielectric properties of a modified liquid are strongly influenced by the type of the nanoparticles added. With the addition of one type of nanoparticles, the breakdown voltage of the liquid is much increased while the streamer propagation velocity is reduced. With the addition of another type of nanoparticles, the degree of scatter of breakdown data is improved, and thus the low probability value of breakdown is increased. The latter will increase the reliability of the insulation system or saying that there is a potential to increase the design values of the insulation system. A charging dynamic model is discussed. A trend has been seen from this study that nanofluids have potential for being used in transformer insulation liquid.