Accelerated Thermal Ageing on Electrical and Physicochemical Performance of Palm Oil Methyl Ester-Based Nanofluids as Liquid Insulation in Transformers

• Main Author: Sharifah Masniah, Wan Masra
• Format: Thesis
• Language: English; English; English
• Published: UNIMAS 2024
• Subjects: TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://ir.unimas.my/id/eprint/45076/3/DSVA_SharifahMasniahWM.pdf; http://ir.unimas.my/id/eprint/45076/4/Thesis%20PhD_SharifahMasniahWanMasr.ftext.pdf; http://ir.unimas.my/id/eprint/45076/5/Thesis%20PhD_SharifahMasniahWanMasr%20-%2024%20pages.pdf; http://ir.unimas.my/id/eprint/45076/
• Institution: Universiti Malaysia Sarawak

The paradigm shift from non-biodegradable and non-renewable mineral oil to acceptable biodegradable, renewable, and safer alternatives has prominently emerged in response to the United Nations Sustainable Development Goal (SDG)-7. However, their high viscosity, low dielectric strength, and poor oxidation stability prevent the broader usage as a replacement for dielectric liquid in transformers. Driven by the need for elevated properties of vegetable oils to align with the industry standards, the conversion process of the triglycerides, combined with modifications through the addition of nanoparticles and a surfactant, has been investigated. This thesis proposes enhancing the properties of refined, bleached, and deodorised palm oil olein (RBDPOo) through chemical modification using a transesterification process to produce palm oil methyl ester (POME) as the base fluid. Additionally, semiconductive titanium dioxide (TiO2) and conductive multi-walled carbon nanotube (MWCNT) nanoparticles, along with the hexadecyltrimethylammonium bromide (CTAB) surfactant, are added. Accelerated ageing experiments were conducted in a sealed condition at a temperature of 130 oC over a duration ranging from 0 to 1000 h for 0.01−0.10-g/L concentrations to understand their degradation behaviour. Overall, the findings demonstrated that all POME-based nanofluids showed an increase in AC BDV during the accelerated thermal ageing study, with the highest average value recorded at 57.08 kV, indicating a remarkable increment of 157.7% for POME-based TiO2 nanofluid at a concentration of 0.05-g/L. After being subjected to accelerated thermal ageing, the BDV of POME-based TiO2 nanofluids revealed a consistent trend across various doping concentrations. It was demonstrated that the proposed POME-based nanofluids performed comparably with other types of methyl ester oils in terms of breakdown voltage, kinematic viscosity, and flash point.