Transformer Overhaul Project：
Ⅰ Lift open the bell jar or lift out the body for inspection.
Ⅱ Maintenance of coils, leads and magnetic (electrical) shielding devices.
Ⅲ Inspection of the iron core, iron core fasteners (through-core screws, clamps, drawstrings, straps, etc.), pressure nails, connecting pieces and grounding pieces.
Ⅳ Maintenance of fuel tanks and accessories, including casings, moisture absorbers, etc.
Ⅴ Maintenance of ancillary equipment such as coolers, oil pumps, water pumps, fans, valves and pipelines.
Ⅵ Inspection and maintenance of safety protection devices.
Ⅶ Calibration of temperature measuring devices and calibration of gas relays.
Ⅷ Maintenance and testing of operating control boxes.
Ⅸ Maintenance of off-excitation tap-changer or on-load tap-changer.
Ⅹ Replacement of all gaskets and leak testing of components.
Ⅺ Dry the insulation of the body if necessary.
Ⅻ Transformer oil treatment or oil change.
XIII Testing and commissioning after overhaul.
XIV Technical transformation projects that can be carried out in conjunction with transformer overhaul (such as strengthening the mechanical strength of the oil tank, changing the internal grounding device of the body to external grounding, improving the oil level gauge, and installing a sealing device on the oil conservator).
XV Finally, the tank is cleaned and spray painted.
Overhaul process：
Remove the leads→electrical and oil preparation test, insulation judgment→partially drain the oil, disassemble the accessories and inspect them→drain the oil and dispose of it, remove the tap changer connecting parts→inspect the bell jar (body), inspect the body, inspect and test the insulation→moisture Then drying treatment→Inject oil according to the prescribed oil injection method→Install accessories such as bushings and coolers→Sealing test→Oil level adjustment→Electrical and oil testing→End.