Technical Analysis Of Pre-insulated Bushings In Power Systems

The insulation structure of pre insulated sleeve is pre-designed and processed, integrating multiple layers of insulation materials. For different voltage levels from 35kV to 500kV, the pre insulated junction sleeve requires the selection of the corresponding material system based on the field strength distribution characteristics. A ceramic outer jacket provides an external insulation barrier, while the internal capacitor core achieves electric field homogenization through concentric cylindrical electrodes. The oil-paper composite material forms the main insulation layer within the sealed cavity.

The impregnation process during manufacturing directly affects the performance of insulated joint sleeve. The insulating paper is vacuum-dried and then impregnated with treated transformer oil to form a dense oil-paper insulation system. The sealing structure at the flange uses oil-resistant rubber gaskets, which, combined with the clamping force applied by springs, maintain long-term airtightness. The contact resistance between the conductive rod and the end connector must be controlled within the design range; excessive resistance will lead to abnormal localized temperature rise.