[حمید]

لطفاً به متن زیر که از مراجع معتبر اخذ شده توجه فرمائید. After successful erection, some development work is to be done before starting precommissioning test. The development work includes the following: -Topping up of oil: Final topping up is done with clean, dry and tested oil upto a level in the conservator commensurate with filling oil temperature. -Air release: Since bushings used in distribution transformer are of oil communicating type, the trapped air inside the bushings should necessarily be removed before commissioning in order to allow the oil to come upto the top of the bushing terminals. This will reduce the possibility of corona discharge considerably. -Trapped air inside the tank cover should also be removed through air release plug, if provided, on the tank cover. -If radiators have air release plugs on top, the same should be operated to release trapped air, if any, from the radiators. -Air from buchholz relay and explosion vent (if equalizer pipe not provided) should be released at this stage. -Any other plug for releasing trapped air from the transformer, if provided, should also be operated. -After completion of all the release operations, the oil level should be checked further to see that it is up to normal level. -Test on buchholz relay: The slope of mounting angle of buchholz relay is checked with a spirit level to ensure that the inclination of pipe is approximately 5 to 10