Dielectric and thermal response of TiO2 and SiC natural ester based nanofluids for use in power transformersDielectric and thermal response of TiO2 and SiC natural ester based nanofluids for use in power transformers Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2023-12-062022enThe improvement of dielectric and thermal properties of insulating oils used in High Voltage (HV) equipment has been a key part of research over the last three decades. In this study, a natural ester oil is used as matrix oil and dispersions of two semi-conducting nanoparticles (NPs), titanium oxide (TiO 2 ) and silicon carbide (SiC), are prepared in 0.004 weight percentage ratio (0.004% w/w). In terms of thermal features, thermal diffusivity and thermal conductivity are measured over a large temperature range between 25 and 90 oC . By means of the dielectric properties, the Lightning Impulse Breakdown Voltage (LI BDV) of nanofluids (NFs) is measured and compared to the corresponding ones of the matrix. Moreover, the dielectric constant and dielectric dissipation factor (DDF) are determined for the NF and matrix samples in the frequency range of 1 to 10 6 Hz. The obtained results show that the NF containing SiC NPs is characterized from the greatest increase in thermal conductivity, by 58% with respect to natural ester oil’s, as well as the lowest dielectric constant in both 25 and 90 oC , most likely due to their higher permittivity and thermal conductivity. Lastly, the LI BDV of the same NF is the most enhanced, by 10% relatively to the matrix, while a numerical model in COMSOL Multiphysics is developed and is found to successfully verify the LI BDV results.http://creativecommons.org/licenses/by/4.0/IEEE Access1079222-79236Koutras_et_al_IEEE Access_10_2022.pdfChania [Greece]Library of TUC2023-12-06application/pdf2.1 MBfree Koutras Konstantinos Peppas Georgios D. Fetsis Timotheos Tegopoulos Sokratis Charalampakos Vassilios P. Kyritsis Apostolos Yiotis, Andreas Gonos Ioannis Pyrgioti, Eleftheria Institute of Electrical and Electronics Engineers Insulating nanofluid Lightning impulse Dielectric constant Thermal conductivity Numerical model