Abstract: At least one conductor is disposed in sealed vessel, which is filled with insulating gas, an hand hole is provided to a part of sealed vessel and is closed by a sealed cover, and optical fibers are disposed that form a closed loop surrounding conductor in sealed vessel. Optical fibers are hermetically led out of sealed vessel from sealed cover and are provided with at least a light source unit and an optical signal processor unit at the lead-out end. An airtight hollow tube disposed looping around leaving a predefined distance of separation is provided to conductor in sealed vessel, the end of tube is hermetically connected to sealed cover by sealing/bonding means, and optical fibers can be inserted in sealing/bonding means.

Abstract: An installation base is secured to part of outer peripheral surface of cylindrical container 1 which has electric conductor 2 arranged thereinside, and a case which stores a Faraday-effect element is detachably secured to the installation base. Faraday-effect element 10 having two optical fibers 24A, 24B of prescribed dimensions, to provide first and second optical paths 11A, 11B maintained in parallel with a predetermined interval therebetween and placed so as to intersect axial direction of electric conductor 2, and having mirror 12 which reflects linearly polarized light at one end surface of each optical fiber. Linearly polarized light from the same light source injected into each of the optical paths 11A, 11B, and current flowing in electric conductor 2 is measured base on the Faraday rotation angle of the linearly polarized light reflected and returned from mirror 12.

Abstract: Insulating spacer 1 has insulating molded member 3 molded as a single body with insulating material such as epoxy resin, in which at least one electric conductor 2, a grounding shield surrounding the electric conductor(s), and Optical fiber 14 of Faraday-effect element are embedded to form a build-in configuration. The grounding shield can be formed of cylindrical shielding member 15 made of metal wires, metal strips, or a cylindrical metallic member having a perforation of a plurality of small holes thereon. The aforementioned optical fiber 14, which is to be used as a component of an optical current transformer, is put in a certain place in cylindrical shielding member 15.

Abstract: At least one conductor is disposed in sealed vessel, which is filled with insulating gas, an hand hole is provided to a part of sealed vessel and is closed by a sealed cover, and optical fibers are disposed that form a closed loop surrounding conductor in sealed vessel. Optical fibers are hermetically led out of sealed vessel from sealed cover and are provided with at least a light source unit and an optical signal processor unit at the lead-out end. An airtight hollow tube disposed looping around leaving a predefined distance of separation is provided to conductor in sealed vessel, the end of tube is hermetically connected to sealed cover by sealing/bonding means, and optical fibers can be inserted in sealing/bonding means.

Abstract: Insulating spacer 1 has insulating molded member 3 molded as a single body with insulating material such as epoxy resin, in which at least one electric conductor 2, a grounding shield surrounding the electric conductor(s), and Optical fiber 14 of Faraday-effect element are embedded to form a build-in configuration. The grounding shield can be formed of cylindrical shielding member 15 made of metal wires, metal strips, or a cylindrical metallic member having a perforation of a plurality of small holes thereon. The aforementioned optical fiber 14, which is to be used as a component of an optical current transformer, is put in a certain place in cylindrical shielding member 15.

Abstract: An installation base is secured to part of outer peripheral surface of cylindrical container 1 which has electric conductor 2 arranged thereinside, and a case which stores a Faraday-effect element is detachably secured to the installation base. Faraday-effect element 10 having two optical fibers 24A, 24B of prescribed dimensions, to provide first and second optical paths 11A, 11B maintained in parallel with a predetermined interval therebetween and placed so as to intersect axial direction of electric conductor 2, and having mirror 12 which reflects linearly polarized light at one end surface of each optical fiber. Linearly polarized light from the same light source injected into each of the optical paths 11A, 11B, and current flowing in electric conductor 2 is measured base on the Faraday rotation angle of the linearly polarized light reflected and returned from mirror 12.

Abstract: Provided is a capacitor system which makes the best use of the performance of capacitors while reducing power loss. The capacitor system includes a plurality of capacitors, parallel monitors which are respectively connected in parallel to the capacitors and initialize voltages of the capacitors to a predetermined value, a plurality of changeover switches which function to switch a connection state of the capacitors connected in series, and a bank switching function of switching the connection state of the capacitors by alternately turning the changeover switches on and off to provide a predetermined voltage. The changeover switches are alternately turned on and off while maintaining a simultaneous ON time to ensure continuous flow of a charge/discharge current.