Abstract: Disclosed is installation of an optical fiber composite electric power cable. An installation method of an optical fiber composite electric power cable includes installing an electric power cable including a conductor and an air-blown installation tube therein at an installation region; connecting tubes of adjacent electric power cables to each other, in an electric power cable connection box; and installing an optical fiber unit into the connected tubes by air pressure. Also, a cable structure used for installing the optical fiber composite electric power cable includes a conductor for electric power transmission; an insulator surrounding the conductor; an air-blown installation tube provided out of the insulator; and a corrosion-protective layer provided to an outermost layer of the cable.

Abstract: A fuel cell system a includes a cooling water temperature raising unit that raises the temperature of a fuel cell stack by passing discharge gas of a process burner or hydrogen gas of a fuel processing unit and cooling water that is heated by the discharge gas of the process burner through flow paths formed on opposing surfaces of cooling separators formed of a metal and installed between a plurality of cells in the stack. Thus in the fuel cell system, when the temperature of the stack needs to be rapidly raised, for example, during a start up operation of the fuel cell system, the temperature of the stack can be rapidly raised using discharge gas at a high temperature or combustion heat of hydrogen gas, and heated cooling water, and thereby, significantly reducing the time required for the fuel cell system to be in regular operation.

Abstract: A fuel cell system includes a first heating structure that increases an internal temperature of the stack by passing exhaust gas of the process burner through the stack; and a second heating structure that increases the internal temperature of the stack by passing heated cooling water through the stack after the cooling water is heated by heat exchange with the exhaust gas of the process burner. Accordingly, when rapid heating of a stack is necessary like during a start up operation, a time required for the fuel cell system to reach a normal operation can be greatly reduced since the stack can be simultaneously heated using high temperature exhaust gas and heated cooling water.

Abstract: An underground power cable having an optical fiber sensor for measuring temperature distribution is disclosed. In the power cable, an optical fiber for measuring temperature distribution is received in a stainless steel tube having excellent strength, and this optical tube is interposed between a core and a sheath of the power cable. When arranging the optical tube in the power cable, a supporting material having a relatively low strength than the optical tube is arranged in the cable together in order to prevent the optical fiber from being damaged by external force and prevent the inner insulation layer from being broken down by the optical tube. In addition, a fixing tape for fixing the optical tube in contact with the core may be added to prevent the optical tube from being bent seriously or inclined to one side when the cable is bent.

Abstract: Apparatus and method for real-time analysis of an electric power transmission link status direct buried or installed in a duct or a tunnel are described. The method includes: real-time measuring a surface distributed temperature of the link by using a distributed temperature sensor installed along a longitudinal direction of the link; calculating a conductor temperature of the link on the basis of the surface distributed temperature and an electric current flowing through the link; calculating a heat flow emitted out of the link on the basis of the surface distributed temperature and the conductor temperature; and real-time calculating a thermal parameter of an environment around the link on the basis of the heat flow. Thus, it is possible to calculate operating conditions of the link more accurately and improve safety of electric power transmission by real-time calculating the thermal parameter of the environment around the link.

Abstract: Apparatus and method for real-time analysis of an electric power transmission link status direct buried or installed in a duct or a tunnel are described. The method includes: real-time measuring a surface distributed temperature of the link by using a distributed temperature sensor installed along a longitudinal direction of the link; calculating a conductor temperature of the link on the basis of the surface distributed temperature and an electric current flowing through the link; calculating a heat flow emitted out of the link on the basis of the surface distributed temperature and the conductor temperature; and real-time calculating a thermal parameter of an environment around the link on the basis of the heat flow. Thus, it is possible to calculate operating conditions of the link more accurately and improve safety of electric power transmission by real-time calculating the thermal parameter of the environment around the link.

Abstract: An underground power cable having an optical fiber sensor for measuring temperature distribution is disclosed. In the power cable, an optical fiber for measuring temperature distribution is received in a stainless steel tube having excellent strength, and this optical tube is interposed between a core and a sheath of the power cable. When arranging the optical tube in the power cable, a supporting material having a relatively low strength than the optical tube is arranged in the cable together in order to prevent the optical fiber from being damaged by external force and prevent the inner insulation layer from being broken down by the optical tube. In addition, a fixing tape for fixing the optical tube in contact with the core may be added to prevent the optical tube from being bent seriously or inclined to one side when the cable is bent.