Abstract: A power cable includes a conductor, an inner semi-conductive layer covering the conductor, an insulating layer covering the inner semi-conductive layer and impregnated with insulating oil, an outer semi-conductive layer covering the insulating layer, a metal sheath layer covering the outer semi-conductive layer, and a cable protection layer covering the metal sheath layer. A minimum thickness t1 of a certain cross section of the metal sheath layer is less than or equal to 90% of a maximum thickness t2 thereof.

Abstract: A power cable includes a conductor; an inner semi-conductive layer covering the conductor; an insulating layer covering the inner semi-conductive layer, the insulating layer being impregnated with an insulating oil; an outer semi-conductive layer covering the insulating layer; a metal sheath layer covering the outer semi-conductive layer; and a cable protection layer covering the metal sheath layer. The insulating layer is formed by cross-winding insulating paper and impregnating the insulating paper with the insulating oil. The inner semi-conductive layer and the outer semi-conductive layer are formed by cross-winding semi-conductive paper and impregnating the semi-conductive paper with the insulating oil. A thickness of the outer semi-conductive layer is 7.5 to 15% of a total thickness of the inner semi-conductive layer, the insulating layer, and the outer semi-conductive layer.

Abstract: Provided is a power cable, particularly, an ultra-high voltage underground or submarine cable for long-distance direct-current transmission. More specifically, the present invention relates to a power cable, in which an insulating layer has high dielectric strength, an electric field applied to the insulating layer is effectively reduced, and particularly, a void is suppressed from occurring in the insulating layer due to contraction of insulating oil, caused by a decrease of temperature in the insulating layer under a low-temperature condition or when the supply of an electric current is stopped, thereby effectively suppressing partial discharge, dielectric breakdown, etc. due to an electric field concentrated in the void.

Abstract: Provided is a power cable, particularly, an ultra-high voltage underground or submarine cable for long-distance direct-current transmission. More specifically, the present invention relates to a power cable, in which an insulating layer has high dielectric strength, an electric field applied to the insulating layer is effectively reduced, and particularly, a large void is suppressed from occurring in the insulating layer when the power cable is left at low temperatures for a long time until electric current is supplied thereto after installed in a low-temperature environment, thereby effectively preventing partial discharge, dielectric breakdown, etc. from occurring due to an electric field concentrated in the large void.

Abstract: An apparatus for producing an optical fiber preform to perform the deposition process by modified chemical vapor deposition. The Apparatus comprises a main heat source location sensor (800) for detecting the location of a main heat source for heating a substrate tube 100, an additional supporting device control part (1000) wiredly or wirelessly connected to the main heat source location sensor (800), and an additional supporting device (1100) wiredly or wirelessly connected to the additional supporting device control part (1000) for supporting the substrate tube (100). The present invention reduces the effective length of the substrate tube (100) by additionally supporting the substrate tube (100), thereby minimizing the deflection of the substrate tube (100). Particularly, it is possible to considerably reduce the deflection of the substrate tube at its initial part and thus to achieve a high deposition efficiency. Accordingly, it is possible to mass-produce an optical fiber preform of high quality.

Abstract: A method for producing an optical fiber cable which improves stability by attaching an Aramid yarn near the core in parallel to an axial direction of the optical cable and solves structural problems of the cable by soaking an Aramid yarn into an epoxy resin is disclosed. This optical cable producing method uses a tensile material for improvement of tensile property, and includes the steps of soaking the tensile material into an epoxy resin, and attaching the tensile material to the optical cable in parallel to the axial direction of the optical cable.

Abstract: A method for producing an optical fiber cable which improves stability by attaching an Aramid yarn near the core in parallel to an axial direction of the optical cable and solves structural problems of the cable by soaking an Aramid yarn into an epoxy resin is disclosed. This optical cable producing method uses a tensile material for improvement of tensile property, and includes the steps of soaking the tensile material into an epoxy resin, and attaching the tensile material to the optical cable in parallel to the axial direction of the optical cable.

Abstract: In an optical fiber drawing apparatus capable of drawing one piece of an optical fiber, the present invention provides an optical fiber drawing apparatus which is adapted to decrease a break of an optical fiber to be adjusted a curvature radius thereof by at least one or more moving rollers continuously installed after a fixing roller and to decrease a polarization mode dispersion (PMD) by a birefringence which is not desired in an optical fiber.