Abstract: By combining magnetically shielding members of various different properties with each other, a magnetically shielding capability of a magnetically shielding structure is made to improve and a greatly reduced magnetic field, as compared to an external one, can be realized effectively. The penetrating magnetic field has a distribution, on the longitudinal axis of a cylindrical shielding body made of a material manifesting a Meissner effect, which attenuates toward the center direction of the cylindrical shielding body. Magnetic induction is generated in a cylindrical collar made of a highly permeable material. Then, the penetrating magnetic field is shorted magnetically, being absorbed by the highly permeable material.

Abstract: A power cable having a plastic electrical insulation which is partially or wholly composed of a plastic compound. The plastic compound containing an inorganic or organic electrolyte which ionizes when dissolved in water, the power cable prevents the deterioration of insulation called "water tree" which has been a fatal drawback of the plastic insulation layers of the conventional plastic insulated cables such as cross-linked polyethylene cables, etc.