Thermal degradation analysis of pongamia pinnata oil as alternative liquid dielectric for distribution transformer

Abstract

In this paper the feasibility of non-edible pongamia pinnata oil (PPO) as an alternative liquid dielectric which can be used in distribution transformers is examined. Hence, electrical, physical and chemical properties have been measured for thermally aged (with and without catalytic added) pongamia pinnata oil (PPO) and mineral oil (MO), sampled at 110°C for 180 days (according to IEC and IS standard). The experiment results show that, electrical properties of pongamia pinnata oil with catalytic (PPOWC) are better than those of mineral oil with catalytic (MOWC). Whereas, the viscosity and density of PPOWC sample is much higher at all sampling intervals, so that care must be taken for cooling tube design of transformer. Furthermore, for all aging period the total acid content in MOWC oil samples is very low compared to PPOWC. However, these are higher molecular weight acid which is beneficial than lower molecular weight acid generated by MOWC oil samples.