ABSTRACT
This chapter highlights recommendations for the proper receipt, inspection, field assembly, oil processing, acceptance testing, and maintenance of large liquid-immersed power transformers rated 10 MVA or greater or with primary voltage rating of 69 kV and above. Any removed bushing turrets should be installed. Some turrets have current transformers installed. Sometimes the current transformer may be suspended from transformer cover (drop in mounting) and may need to be rotated and elevated in its mounting before installation of turret. Statistically, failure of bushings is one of the top five reasons that transformers fail in service. Failure of a bushing can lead to severe damage to the transformer. Therefore, it is critical to properly maintain these critical components. Any oil leaks observed during mechanical maintenance should be corrected as these are the primary source for moisture and oxygen exchange with the insulation system.
