Mineral and Ester Nanofluids as Dielectric Cooling Liquid for Power Transformers

Abstract

Amidst the new techniques facing the improvement of cooling and insulating efficiency and the design of electric transformers, constrained by the current technologies, one of the more promising is the substitution of traditional dielectric oils for nanofluids. Research on nanofluids for their application in transformers as a coolant and dielectric medium have been performed during the last two decades and continue today. This review tries to collect and analyze the available information in this field and to offer it already dissected to researchers, focusing on the preparation methods and how nanoparticles affect the main properties of the base fluids. Here we also addressed the influence of different parameters as particle characteristics or environmental conditions in nanofluids performance, the evolution with time of the measured properties, or the neighboring relationship of nanofluids with other transformer components. In this sense, the most reviewed articles reflect enhancements of thermal conductivity or dielectric strength, as well as an improvement of time evolution of these properties, with respect to those that are found in base fluids, and, also, a better interaction between these nanofluids and dielectric cellulosics. Thus, the use of dielectric nanofluids in transformers may allow these machines to work safer or over their design parameters, reducing the risk of failure of the electrical networks and enhancing their life expectancy. Nevertheless, these advantages will not be useful unless a proper stability of nanofluids is ensured, which is achieved in a small part of revised articles. A compendium of the preparation methodology with this aim is proposed, to be checked in future works.

Modification of insulating oils and oil-based titanium dioxide nanofluids for transformers: a review

“…Oil-based TiO 2 NFs maintained their dispersion over 12 days but showed signs of precipitation. 70 Due to the dielectric properties of NFs, some samples remained stable after 4 weeks, particularly those at lower concentrations. In addition, where AC BDV measurements were repeated for several weeks after NF preparation, it was found that the standard deviation of the measurements was increasing and the average AC BDV of all NFs decreased over time, possibly due to the increasing formation of aggregates.…”

Polyalphaolefin Oil/MgO-20 Nanofluids Coating Shows Corrosion Resistance, High Moisture Resistance, and Water Resistance for Electrical and Electronic Equipment

“…Coatings with metal oxide nanoparticles tend to interact with the metal surface to be protected and form thin nanofilms on the metal surface by deposition time [22,23]. The presence of metal oxide nanoparticles in fluids has been proven to cause an increase in insulation resistance [24,25], anti-corrosion performance [13], and heat transfer of the surface to be protected [26,27].…”

Influence of Mineral Oil-Based Nanofluids on the Temperature Distribution and Generated Heat Energy Inside Minimum Oil Circuit Breaker in Making Process

“…Thi temperature causes an erosion of the contacts and shortens the lifetime of the breaker as a whole. Researchers recently studied the development of nanoparticle dispersion in base insulating oil, known as nanofluids, to improve the dielectric and thermal prop of base oil [4,5]. For dielectric properties, using nanofluids enhanced breakdown st [5,6], dielectric dissipation factor [5,7], partial discharge resistance [8], and cre discharge [9].…”

“…In [13,14], graphene oxide could improve the dielectric strength prepared nanofluids without monitoring thermal properties, while, in [15], gra oxide could improve both the dielectric strength and thermal conductivity of pre nanofluids. In [16,17], simultaneous enhancements in thermal conductivity and die Researchers recently studied the development of nanoparticle dispersion into the base insulating oil, known as nanofluids, to improve the dielectric and thermal properties of base oil [4,5]. For dielectric properties, using nanofluids enhanced breakdown strength [5,6], dielectric dissipation factor [5,7], partial discharge resistance [8], and creepage discharge [9].…”

“…In [16,17], simultaneous enhancements in thermal conductivity and die Researchers recently studied the development of nanoparticle dispersion into the base insulating oil, known as nanofluids, to improve the dielectric and thermal properties of base oil [4,5]. For dielectric properties, using nanofluids enhanced breakdown strength [5,6], dielectric dissipation factor [5,7], partial discharge resistance [8], and creepage discharge [9]. For thermal properties, both the thermal conductivity and the heat transfer coefficient have been investigated.…”