Introduction to Transformer Bushing

The sleeve is mainly composed of a capacitor core, oil conservator, flange, and upper and lower porcelain sleeves. The main insulation is the capacitor core, which is composed of concentric capacitors connected in series and enclosed in a sealed container composed of upper and lower porcelain sleeves, oil conservator, flange, and base. The container is filled with processed transformer oil, making the internal main insulation an oil paper structure. The contact surface between the main components of the casing is lined with oil resistant rubber gaskets. Each component is fully sealed inside the casing by the central clamping force applied by a set of strong springs installed in the oil storage tank. The flange is equipped with a vent plug, an oil extraction device, and a measuring sleeve medium loss (tan δ， Devices for dielectric loss and partial discharge (PD). The outer cover of the measuring device must be covered during operation to ensure that the final screen is grounded and open circuits are strictly prohibited. There are two connection methods between the bushing and the high-voltage lead of the transformer: cable threading and current carrying through the guide rod.

The casing should be used according to its model under its specified conditions, and the following precautions should be taken.

(1) Ensuring casing sealing is the key to achieving durability. The sealing structure position moved by the user during installation and maintenance should be carefully restored to its original sealing state.

(2) Oil level control and adjustment. Regularly observe the changes in the oil level inside the casing during operation, and adjust whether it is too high or too low. When the oil level is too high, an appropriate amount of oil can be drained from the flange oil plug. When the oil level is too low, transformer oil with the same grade as the one marked on the nameplate and qualified after treatment should be added from the oil filling port of the oil storage tank. For products with normal oil performance in previous preventive tests, the cycle of preventive tests can be appropriately extended to reduce oil extraction. If you have any questions, please contact the manufacturer. It is strictly prohibited to disassemble this sleeve on your own.

The correct oil extraction steps are: clean the dirt at the flange oil plug, open the oil plug, use a dedicated oil nozzle, slowly screw in along the center screw hole of the oil plug, counter the plug inside and tighten it, press the sealing ring of the oil nozzle, and at this time, the transformer oil in the sleeve will flow out along the inner hole of the oil extraction nozzle; After removing the oil, follow the above process in reverse order to restore it.

Attention: When unscrewing the oil nozzle, do not loosen the oil plug. If any looseness is found, use a 19mm socket wrench on the opposite side to tighten the oil plug in a timely manner.

(3) The measuring terminals must be reliably grounded. There is a measuring terminal at the flange where the sleeve is installed. When measuring the dielectric loss and partial discharge of the sleeve, the terminal cover is unscrewed, and the terminal post is insulated from the flange. After the measurement is completed, the terminal cover must be covered to ensure reliable grounding. Open circuit is strictly prohibited during operation.

(4) The measured dielectric loss value at 10kV on site may be inconsistent with the factory test data due to the influence of measuring instruments, product location, and measurement environment.