Evaluation of Food Grade Corn Oil for Electrical Applications

Petroleum-based insulating liquids are applied in several items of electrical power equipment, in which they serve as a dielectric as well as a coolant. However, these oils are environmentally toxic and inflammable, require costly fire protection schemes and deluge systems. To overcome this problem, seed-based vegetable oils have been investigated since these are biodegradable, non-toxic, and posses high fire point. In this experimental investigation, a local brand of seed-based corn oil is evaluated so as to be adopted as a viable dielectric fluid. It was characterized through a series of dielectric and physio-chemical properties and compared with mineral insulating oil. Results show that its 60 Hz breakdown strength is much higher than the mineral oil, while tan δ values satisfy IEC-60156 set criteria. Higher values of permittivity will enable favorable field distribution across oil-cellulose composite insulation. Under oxidation in presence of copper catalyst, it exhibits much less degradation than in mineral oil since its acidity is decreased. It therefore offers a more cost effective replacement solution, in particular for electrical applications in under developed and developing countries where the mineral-based oils are expensive due to a price hike in petroleum crudes.