抄録
To compactize EHV XLPE power cables and joints has been very important requirements among utilitiy companies and so we developed a new method to improve the breakdown strength at the semicon-interface in a mold-type cable joints in order to fulfil the requirements. The method was named as “Interface Diffusion Method” and is based on an additive mixed into semicon layer of an XLPE power cable joint. We found that the additive, conventional surfctant, diffused into insulation layer during heating process at cable jointing. The additive improves the lamellar orientation at the interface and forms a diffusion layer near the interface, and consequently increase the breakdown strength at the interface. The method was applied to XLPE power cable joints models with insulation thickness up to 9 mm and the model passed a voltage endurance test for 154kV cable joint.
This paper describes some experimental results in terms of the breakdown strength and material analysis of XLPE insulation at the interface in the mold with a transmission electron microscope (TEM). TEM analysis showed that the lamellar orientation in the XLPE insulation at the interface is improved as well as that in the XLPE insulation in the cable part.
