Investigation of Survival/Hazard Rate of Natural Ester Treated with Al2O3 Nanoparticle for Power Transformer Liquid Dielectric

Abstract

Increasing usage of petroleum-based insulating oils in electrical apparatus has led to increase in pollution and, at the same time, the oils adversely affect the life of electrical apparatus. This increases the demand of Mineral Oil (MO), which is on the verge of extinction and leads to conducting tests on natural esters. This work discusses dielectric endurance of Marula Oil (MRO), a natural ester modified using Conductive Nano Particle (CNP) to replace petroleum-based dielectric oils for power transformer applications. The Al2O3 is a CNP that has a melting point of 2072 °C and a low charge relaxation time that allows time to quench free electrons during electrical discharge. Al2O3 is blended with the MRO and Mineral Oil (MO) in different concentrations. The measured dielectric properties are transformed into mathematical equations using the Lagrange interpolation polynomial functions and compared with the predicted values either using Gaussian or Fourier distribution functions. Addition of Al2O3 indicates that 0.75 g/L in MRO has an 80% survival rate and 20% hazard rate compared to MO which has 50% survival rate and 50% hazard rate. Considering the measured or interpolated values and the predicted values, they are used to identify the MRO and MO’s optimum concentration produces better results. The test result confirms the enhancement of the breakdown voltage up to 64%, kinematic viscosity is lowered by up to 40% at 110 °C, and flash/fire points of MRO after Al2O3 treatment enhanced to 14% and 23%. Hence the endurance of Al2O3 in MRO proves to be effective against electrical, physical and thermal stress.

Assessing Electrical and Physicochemical Performance of Chemically Modified Palm Oil as an Alternative Transformer Liquid

“…PKO. In other studies, for instance, Raj et al (2021) reported the excellent performance of marula oil blended with Al 2 O 3 by showing up to 64.00% on its breakdown voltage (BDV) enhancement, and Duzkaya and Beroual (2021) reported the increment of AC BDV of FR3 blended with ZnO at 0.1 to 0.3 g L -1 concentrations. On the other hand, some types of NPs do not constantly improve the dielectric strength of NEOs, which others have also reported.…”

“…Several plant oils, such as palm oil, pongamia pinnata oil, olive oil, marula oil, coconut oil, etc., have been used as the raw materials. Their potential suitability as transformer oils has been investigated and examined thoroughly by many researchers (Ariffin et al, 2017;Baruah et al, 2019;Farade et al, 2020;Genga Devi et al, 2016;Koutras et al, 2020a;Samikannu et al, 2021). Researchers eventually realised that VO-based liquid insulation needed various modifications to overcome its shortcomings and be employed as the insulating liquid in transformers (Moosasait and Maria Siluvairaj, 2021).…”

Breakdown Voltage Prediction by Utilizing the Behavior of Natural Ester for Transformer Applications

“…Any slight change in the breakdown strength of the liquid insulation deteriorates enforce stress on the solid insulation [3]. The breakdown strength is mainly affected by adding water content to the oil or generating polar compounds due to an ionization reaction [4]. This leads to the weakening of the insulation capabilities of solid insulation.…”

High Voltage Insulating Materials—Current State and Prospects

“…The subject of natural ester liquids is continued in the papers [5] and [6]. The first one presents the results of the studies on the electrical behavior of natural ester-based ZnO nanofluids at different concentrations in the range of 0.05-0.4 g/L.…”

“…The authors also conclude that increasing nanoparticles concentration beyond the value of 0.4 g/L reveals the implication of a tunnelling/bridging mechanism that may reduce the value of AC breakdown voltage. In turn, the authors of [6] analyzed the natural ester (Marula Oil) treated with Al 2 O 3 with concentrations varying from 0.1 g/L to 2 g/L and 0.25 g/L. They use mathematical considerations to determine survival and hazard rate.…”