Inspect whether the installation of transformer is complete, crooked, and whether there is any local deformation or vibration.
Inspect whether the transformer shell is complete ans the tightness of connections. Make sure the cases are not damaged.
Inspect whether the surroundings of the transformer are clean and water-free.
Check the ventilation equipment in the distribution room or cabinet.
Make sure that there is no overheating phenomenon in every part of the transformer.
Check whether the wire of the transformer is firm, the position is normal, and the insulation distance around the lead is changed.
Make sure that the connection bolts in the transformer is tight, and the transformer has no abnormal noise.
The electrical connection part of the casing and the wiring board shall be tight and free of overheating. Check whether there is any damages to the transformer, and remove the dirt and dust from the rings.
Inspect he technical data and files of the last maintenance.
Understand the operation condition of the transformer.
Comprehensively check the integrity of the transformer.
Check the phase separation plate and the surrounding screen to make sure there is no damages, discoloration, deformation and discharge marks. Any problem should be dealt with once it was found.
Check whether the coil surface is clean or not as well as the conditions of the insulators. Check whether the parts of the transformer are displaced and loose, whether there is dirt and other material clogging the cooling air duct--use soft brush for cleaning if necessary. Check whether the iron core is smooth, whether there is short circuit or discoloration and dislocation situations of the chips. The dirt accumulated at the bottom of the top and bottom yoke of the iron yoke should be cleaned. If the laminated sheet is warped or irregular, use a wooden hammer or a brass hammer to make it smooth.
Check the firmness and insulation performance of the core, top and bottom clamp, square iron and coil pressure plate.