抄録
Interfaces between two different kinds of materials are usually found in underground high voltage equipment. In composite insulating system, interface usually has been considered as a weak point of electrical insulation. On the other hand, it is widely accepted that electrical deterioration in bulk-manufactured insulation materials usually occurs through treeing. Therefore, it is important to research on interface effects on treeing breakdown characteristics in composite materials. Recently, prefabricated-type joint (PJ) has been developed and used on high voltage cables. In the insulation system of the PJ, there are two interfaces exist. One exists between XLPE/EPR and another between EPR/EX. The interface between EPR/EX is an inclined plane. For clarifying effects of the inclined interface and its inclination angle effect on treeing breakdown characteristics, we have done some experimental investigation by making an interface between XLPE and EX. Results are described in this paper. It is found that interface conditions and their inclination angle have great effects on time of treeing breakdown. With the decreasing of the inclination angle, the time of treeing breakdown is reduced. Effect of silicone oil applied on the interface is different at different inclination angle.
