Enhanced breakdown performance of Anatase and Rutile titania based nano-oils

Abstract

Nano-oils synthesized by dispersing dielectric nanostructures counter common intuition as such nano-oils possess substantially higher positive dielectric breakdown voltage with reduced streamer velocities than the base oils. Nano-oils comprising stable and dilute homogeneous dispersions of two forms of titanium (IV) oxide (TiO 2 ) nanoparticles (Anatase and Rutile) have been experimentally examined and observed to exhibit highly enhanced dielectric breakdown strength compared to conventional transformer oils. In-depth survey of literature yields that research on enhancing insulation properties of mineral oils by utilizing anatase and rutile titania nanoparticles is nought. The present study involves titania dispersed in two different grades of transformer oils, both with varied levels of thermal treatment, to obtain consistent and high degrees of enhancement in the breakdown strength, as well as high degrees of increment in the survival of the oils at elevated electrical stressing compared to the base oils, as obtained via detailed twin parameter Weibull distribution analysis of the experimental observations. The experimental results demonstrate augmentation in the breakdown strength ~79 % enhancement for Anatase and ~51% Rutile at relatively low concentrations of 0.1 wt. %. It is also observed that heat treatment of the nano-oils further enhances the dielectric breakdown performance. Additionally, further enhancements are observed at elevated operational temperatures. Detailed studies on the performance of the nano-oils in presence of variant quantities of moisture have also been put forward. Thegrossly different charging dynamics of dielectric nanoparticles localized within the oil has been proposed to be responsible for efficient electron trapping, leading to decrease in the positive streamer velocity and resulting in high dielectric breakdown voltage. The differences in the performance of anatase and rutile has been explained based on the electronic structure of the two and the affinity towards electron scavenging and the theory has been found to validate the experimental observations. The present study can find prime implications and promise in the field of dielectrics and liquid insulation of power electronics and electrical devices.

Titania‐based transformer nanofluid: a study on the synthesis for enhanced breakdown strength and its humidity ageing

“…The electrons propagating with high velocity under high‐voltages interacts with the water molecules and releases the free electrons due to its inherent polar nature. So the raise in free‐electron density offers the conducting path in TTNF and increases its electrical conductivity, which leads to the reduction of BD voltages [37].…”

“…There exist certain methods to develop moisture in the oil samples, and to feed the saturated nitrogen into the test cell equipped with the gas line is one among that [58]. Katiyar et al [37] developed moisture in anatase and rutile TiO 2 nano oils by leaving it idle in the atmosphere for different time periods, to study its humidity ageing. Vahidi et al [59] studied the humidity ageing of MO for different levels of relative humidity (RH) in the chamber and clearly verified the rapid water absorption occurs at the higher intensity of RH.…”

“…In spite of BD strength enhancement, TNF is prone to stability issues that cause a serious deterioration in its electrical properties which mainly occurs when nanoparticle loading in base oil exceeds a certain level. As it is likely to reduce the effective particle surface area in the base fluid, it tends to form the aggregates due to a strong vanderwaal's attraction force and settles down [35][36][37]. Atiya et al [35] investigated the dispersion behaviour and BD strength of titania-based transformer nanofluid (TTNF) samples prepared for four different weight percentage of TiO 2 ranging from 0.007 to 0.041 with surfactant weight percentage of 0.1 to 0.3 and observed the 27% BDV enhancement as highest for 0.007 wt% (0.06 g/l).…”

A Review on Oil-Based Nanofluid as Next-Generation Insulation for Transformer Application

“…However, Katiyar et al [61] have the opinion that the existence of a surfactant has an insignificant effect on the viscosity, thermal conductivity, and breakdown voltages. Furthermore, Xuan et al reported that the sodium dodecyl benzoic sulphate (SDBS) surfactant remarkably exerts a negative effect on the impinging heat transfer performance and suspension of nanofluids.…”

Breakdown performance of transformer oil in the presence of single‐phase nanocrystalline ZnO and nano‐partial substitution

“…The performance of the insulating oils can be improved by suspending nanoparticles into the transformer oils such as magnetite and semiconductor particles. Also, the improvement is attained by enhancing the thermal characteristics of the insulating oils [2][3][4][5][6][7][8][9][10]. The induced and polarised charges generated on the surface of the nanoparticles play an important role in capturing electrons and then enhancing the dielectric strength of the insulating oils [3].…”