Let’s introduce how transformer bushings operate and are maintained:  

Transformer bushings should be used according to their model under specified conditions, and the following points should be noted.

1.The sealing of the transformer bushing is key to achieving a long lifespan. When users install or maintain it, any displaced seal structures should be carefully restored to their original sealed state.  

2.Oil level control and adjustment. During operation, the oil level inside the transformer bushing should be periodically observed. Both excessively high or low levels need adjustment. When the oil level is too high, release an appropriate amount of oil from the flange oil plug; when the oil level is too low, add treated transformer oil that matches the rating on the nameplate through the oil tank filling port. For products whose oil performance has been normal in previous preventive tests, the preventive testing cycle can be appropriately extended to reduce oil withdrawal. If there is any doubt, contact the manufacturer—this bushing must not be disassembled by yourself.  

Correct oil removal steps:  

Clean the dirt around the flange oil plug, open the oil plug, slowly screw in the special oil nozzle along the center screw hole of the plug, press against the inner stopper and tighten it, compressing the nozzle's sealing ring. At this point, the transformer oil inside the bushing will flow out through the center of the nozzle. After obtaining the oil, reverse the above steps to restore the setup.  

Note: When unscrewing the oil nozzle, do not loosen the oil plug. If it is loose, promptly tighten it with a 19mm socket wrench on the opposite side.  

3.Measuring terminal grounding. The flange where the bushing is installed has a measuring terminal. When measuring the bushing’s insulation loss and partial discharge, unscrew the terminal cover and connect the terminal post to the flange edge. After measurement, put the cover back on to ground it. Do not leave the circuit open during operation.  

4.The insulation loss value measured onsite at 10kV may differ from factory test data due to the measuring instrument, product location, and environment. High-voltage Xilin bridges are used to verify factory data, and the high-voltage measured data should be considered accurate.  

That’s the introduction on how transformer bushings operate and are maintained. We hope it’s helpful for you.