建物内磁界低減に向けた高耐圧ケーブル引下げ導線接続法の検討

抄録

We examined the connection method of the high-voltage cable to the structure for adopting the separate type down-conductor for reducing the internal magnetic field of building. In construction of high-voltage cable type down-conductor, it is necessary to minimize safety separation distance considering side lightning flash. For this purpose, it is necessary to reduce the overvoltage generated between the sheath conductor of the cable and the structure of building as small as possible. Therefore, in order to achieve both reductions of the internal magnetic field of the building and of the overvoltage between the cable and the structure, the matching resistances for reducing the reflection inside the cable and for reducing the reflection between the cable and the structure are calculated, and introduced into the analytical model of the building. We confirmed that the internal magnetic field of the building and the overvoltage between the cable and structure reduced effectively by connecting the matching resistance between the sheath conductor and the building pillars. On the other hand, the matching resistance between the core and the sheath conductor in the cable can suppress the reflection inside the cable does not effect for reducing both the internal magnetic field and the overvoltage.