Reclaiming aged transformer oil with activated bentonite and enhancing reclaimed and fresh transformer oils with antioxidants

Transformers are the vital units of power system and the major dielectric used in transformer is petroleum based mineral oil, which acts both as an insulating medium and potential coolant. This work focuses on reclaiming aged mineral oil using activated bentonite and enhancing the critical characteristics of reclaimed mineral oil and fresh transformer oil using antioxidants. The reclamation is carried by treating 500 ml aged mineral oil with 5 g activated bentonite quantity. Then the treated sample is mixed with different combinations of natural and synthetic antioxidants. The enhancement of fresh transformer oil is carried by adding multiple combinations of antioxidants with different mechanisms like free radical scavenging, metal chelating and synergism. The critical parameters like breakdown voltage, viscosity, flash point and fire point of the samples are calculated using ASTM and IEC specifications before and after adding antioxidants. The recorded parameters prove that the reclaimed aged mineral oil after added with high performance antioxidant combinations can perform superior than base fluids and can be reused in power transformers. Moreover the enhanced fresh transformer oil with antioxidants shows greater improvement and this technique could be possibly employed for reclamation (regenerating) and enhancement of waste insulating oils.