Creepage Phenomena of HPOF Cable

The first failure of HPOF cable in Japan occurred after its 10 year operation. It was quite unexpected, though repair works were studied and most of necessary equipments have been prepared for future requirements. Investigation revealed that the most possible cause is creepage phenomena due to heavy traffic, which might have pushed splices so that the earth shield of stress-relief cone was distorted, resulting in electric breakdown. Experiments were carried out to confirm the presumption which was also analyzed numerically. After repair works including necessary anchoring of splices, the cable is now in service.