Potential application of palm oil products as electrical insulating medium in oil‐immersed transformers
Noor Khairin Mohd, Wilsen Hartanto Lim, Abu Hassan Noor Armylisas, Shoot Kian Yeong
Abstract
Abstract The physico‐chemical and electrical insulating properties of certain palm oil products, including triglyceride oils, fatty acids, fatty esters, and glycerol were evaluated for use in oil‐immersed transformers. The studied triglyceride oils have excellent kinematic viscosity values: 30.25–40.49 mm 2 s −1 at 40°C, 6.46–8.34 mm 2 s −1 at 100°C; flash point: 278–320°C; moisture content: 16–175 mg kg −1 and dielectrical breakdown voltage: 29.1–40.9 kV. Fatty acids and fatty esters have relatively lower kinematic viscosity and flash point values than triglyceride oils. The type of hydrocarbon chain, hydrocarbon chain length and molecular size were shown to have substantial effects on the physico‐chemical and electrical properties of the studied oils. The drying process imposed on refined‐bleached‐deodorized palm olein (RBD POo) has reduced the moisture from 400 mg kg −1 to 100 mg kg −1 and improved the dielectrical strength from 31.1 kV to 76.8 kV. Blending of RBD POo with fatty acids or fatty esters has improved the kinematic viscosity of RBD POo and offers even higher flash and fire points than mineral oil. This study showed that palm oil and palm oil products have strong potential to serve as coolants and may be safer for use in oil‐filled transformers as compared to mineral oil.