The transformer is the most critical apparatus in the electric power network. Reliable operation of it is of foremost concern for a proficient power supply. Therefore, it is vital to safeguard the transformer so that it functions at its highest capacity. In order to achieve it, an improvement in the insulation system is necessary, as the majority of faults in transformers are due to the malfunctioning of the insulation system. Petroleum-based oils are extensively used as insulating liquids in transformers. The latterly evolved field of nanotechnology has encouraged studies on Nanofluids (NFs), which are suitable as liquid insulators. In spite of the advantages of NFs in electrical and thermal behavior compared to their base fluids, further studies are needed to establish their long-standing performances as liquid insulators. In this study, three mineral oil samples, new, mid-aged, and extensively aged, were taken. Nanofluids of 0.02% Al2O3 and 0.02% SiO2 of these oils were prepared. The base fluids and nanofluids were characterized by interfacial tension, acidity, dielectric dissipation factor, resistivity, and electric strength. The nanofluids prepared were subjected to laboratory thermal ageing in the presence of copper and kraft paper for 64 hours at 150 °C. The unaged and laboratory-aged nanofluids were characterized for acidity, Interfacial Tension (IFT), Specific Resistance (SR), Tan Delta (TD), and Dielectric Strength (BDV). It was found through this work that the addition of nanoparticles upgraded the properties of oil samples. The long-term applicability and permanence of nanofluids might depend on catalytic effects. These catalytic effects are derived from the internal assembly materials of the transformer.
- Du B, Li X, Xiao M. High thermal conductivity transformer oil filled with BN nanoparticles. IEEE Trans Dielectr Electr Insul. 2015; 22(2):851-858. https://doi.org/10.1109/ TDEI.2015.7076784
- Reffas A, Idir O, Ziani A, Moulai H, Nacer A, Khelfane I, Ouagueni M, Beroual A. Influence of thermal ageing and electrical discharges on uninhibited olive oil properties. IET Sci Meas Technol. 2016; 10(7): 711-18. https://doi. org/10.1049/iet-smt.2016.0045
- Rajnak M, Kurimsky J, Cimbala R, Conka Z, Bartko P, Suga M, Paulovicova K, Tóthova J, Karpets M, Kopcansky P, et al. Statistical analysis of AC dielectric breakdown in transformer oil- based magnetic nanofluids. J Mol Liq. 2020; 309:113243. https://doi.org/10.1016/j.molliq.2020.113243
- Dean SW, Mansoori GA, Soelaiman TAF. Nanotechnology- An introduction for the standards community. Journal of ASTM International. 2005; 2(6):13110-22. https://doi. org/10.1520/JAI13110
- Choi SUS, Eastman JA. Enhancing thermal conductivity of fluids with nanoparticles. ASME International Mechanical Engineering Congress and Exposition; Washington, DC, USA. 1995; 66:99-105.
- ISO/TS 80004-1:2015- Nanotechnologies- vocabularypart1: Core terms; 2015. p. 3.
- Olmo C, Mendez C, Quintanilla PJ, Ortiz F, Renedo CJ, Ortiz A. Mineral and ester nanofluids as dielectric cooling liquid for power transformers. Nanomaterials. 2022; 12:272. https://doi.org/10.3390/nano12152723 PMid:35957155 PMCid:PMC9370386
- Hanai M, Hosomi S, Kojima H, Hayakama N, Okubu H. Dependence of TiO2 and ZnO nanoparticle Concentration on electrical insulation characteristics of insulating oil. IEEE Conf Electr Insul Dielectr Phenomena (CEIDP); 2013. p. 780-783. https://doi.org/10.1109/CEIDP.2013.6748164
- Lv YZ, Du YZ, Li CR, Qi B, Zhong Y, Chen M. TiO nanoparticle induced space charge decay in thermal aged transformer oil. Appl Phys Lett. 2013; 102(13):132902. https://doi.org/10.1063/1.4799375
- Bianco V, Chiacchio F, Manca O, et al. Numerical investigation of nanofluids forced convection in circular tubes. Appl Therm Eng. 2009; 29(17):3632-3642. https:// doi.org/10.1016/j.applthermaleng.2009.06.019
- Jung JY, Oh HS, Kwak HY. Forced convective heat transfer of nanofluids in microchannels. Int J Heat Mass Transfer. 2009; 52(1):466-472. https://doi.org/10.1016/j. ijheatmasstransfer.2008.03.033
- Lee J, Gharagozloo PE, Kolade B, et al. Nanofluid convection in microtubes. ASME J Heat Transfer. 2010; 132(9):092401 https://doi.org/10.1115/1.4001637
- Maharana M, Bordeori MM, Nayak SK, Sahoo N. Nanofluid-based transformer oil: effect of ageing on thermal, electrical and physicochemical properties. IET Sci Meas Technol. 2018; 12(7):878-8. https://doi.org/10.1049/ iet-smt.2017.0475
- Fluids for electrotechnical applications - Mineral insulating oils for electrical equipment, Standard IEC 60296; 2020.
- Mineral insulating oils in electrical equipment - Supervision and maintenance guidance. Standard IEC 60422; 2013.