1.Ensuring the sealing of dry-type composite wall bushings is key to achieving a durable lifespan. When installing or maintaining, users should carefully restore any moved sealing structure to its original sealed state. Controlling and adjusting oil levels: oil levels inside the bushing should be checked regularly during operation. If the level is too high or too low, adjustments are needed. When the oil level is too high, a proper amount of oil can be released from the flange oil plug; if the oil level is too low, oil that matches the grade indicated on the nameplate and has been properly treated should be added through the oil filling port of the oil tank. 

2.For products that have normal oil performance in preventive tests over the years, the preventive test cycle can be appropriately extended to reduce the amount of oil taken. If there are any doubts, contact the manufacturer. The bushing must not be disassembled by yourself. Correct oil extraction steps: clean the dirt around the flange oil plug, open the oil plug, slowly insert a special oil nozzle along the center thread of the oil plug until it presses against the plug inside, tighten it, and compress the sealing ring of the oil nozzle. At this time, the transformer oil inside the bushing flows out through the inner hole of the oil nozzle; after taking the oil, reverse the above process to restore it. 

3.Note: when unscrewing the oil nozzle, do not loosen the oil plug. If loosened, use a 19mm socket wrench to tighten the oil plug immediately. The measurement terminals must be reliably grounded. There are measurement terminals at the bushing installation flange. When measuring bushing dielectric loss and partial discharge, unscrew the terminal cover. The terminal post is insulated from the flange. After measurement, the terminal cover must be placed back to ensure proper grounding. During operation, opening the circuit is strictly prohibited. 

4.The dielectric loss value measured onsite at 10kV may differ from factory test data due to the measuring instrument, product location, and environmental conditions. Transformer bushings are the main insulation device outside the transformer tank. The transformer winding leads must pass through the insulation bushing to ensure insulation between leads and between leads and the transformer tank, while also fixing the leads. Depending on the voltage level, bushings can be pure porcelain, oil-filled, or capacitive bushings. Pure porcelain bushings are mostly used for transformers of 10kV and below, with a conductive copper rod running through the porcelain tube and air insulation inside; oil-filled bushings are mostly used for 35kV transformers, with oil inside the porcelain tube and a copper rod inside wrapped with insulating paper. Capacitor bushings are used in high-voltage transformers above 100kV, composed of a main insulation capacitor core, upper and lower porcelain insulation, connecting sleeve, oil reservoir, spring assembly, base, grading spheres, measurement terminals, wiring terminals, rubber gaskets, and insulating oil.