The high-voltage windings inside the transformer and the external electrical grid are connected by transformer bushings. They are made to endure high mechanical, thermal, and electrical stressors without losing their insulating integrity. Oil-impregnated paper (OIP), resin-impregnated paper (RIP), and composite bushings are among the various varieties of bushings; each has special qualities and uses.
https://axurhf.blogspot.com/20....24/05/optimizing-tra