Abstract
To establish the reliability of the insulating performance of prefabricated-type joints (PJs), dielectric breakdown characteristics of interface insulation were studied.
Using two types of electrodes, which simulate the interface configuration in actual 275 kV PJ, AC and impulse BDSs, together with long-term performance of the interface, were evaluated under various conditions. Among the many factors which would influence the insulating characteristics of the interface, the effect of the silicone oil layer, as well as the applied external pressure, were examined. It was determined that the BDSs were greatly influenced by silicone oil appllication, by the applied interface pressure, and by the pretreatment of the surface of XLPE insulation. On the basis of the result of experiments, the functions of the silicone oil layer in the insulation interface of the PJ were examined.
The authors concluded that the thinner silicone oil layer in the insulation interface is favorable for the establishment of the insulation interface of the PJ.
