(Electrical Review, March 2004, pp. 14–19).
One of the most critical insulating structures in any transformer is the bushing. Since transformers are a key link in the power supply chain, the inability to perform the required function has major economic implications, backlash etc. The most frequent and dangerous bushing failure is the insulation breakdown of the oil channel along the inner surface of the lower porcelain cover. This failure results usually in the damage of the lower part of the cover, sometimes it is accompanied by throwing of the bushing out of the tank, it's damage and fire, large amount of damage in consequence. That's why during the inspection of this kind of failure the real place of failure origin cannot always be clearly discovered.
Critical insulating structures, Bushing, Transformers, Bushing failure, Damage, Inspection
