Dissolved Gas Analysis Of Flaxseed Oil And Coconut Cooking Oil Blends: Thermal Degradation And Oxidative Stability In Simulated Transformer Conditions

Abstract

The search for sustainable transformer insulating fluids has led to increased interest in biodegradable vegetable oils as alternatives to conventional mineral oils. This research investigates the thermal degradation and oxidative stability of flaxseed oil (100%) and a blend of flaxseed oil (50%) with coconut cooking oil (50%), subjected to thermal aging at 170°C for 5 hours with copper immersion, simulating transformer winding conditions. Dissolved Gas Analysis (DGA) was conducted using Myrkos Portable DGA MicroGC to quantify gas evolution, including H₂, CH₄, CO, CO₂, C₂H₄, C₂H₆, and C₂H₂. The results indicate that flaxseed oil exhibits higher thermal degradation, with elevated concentrations of CO₂, CO, C₂H₄ and C₂H₆, suggesting increased oxidation and hydrocarbon breakdown. In contrast, the flaxseed oil-coconut cooking oil blend demonstrates improved oxidative stability, with lower gas concentrations, indicating enhanced resistance to thermal stress. The presence of copper as a catalytic agent further influences gas formation, accelerating oxidation reactions in both oil samples. These findings highlight the potential of vegetable-based insulating oils as sustainable alternatives for transformer applications. The flaxseed oil-coconut cooking oil blend emerges as a promising candidate due to its enhanced thermal stability, which could contribute to improved performance and longevity in electrical insulation systems.