Abstract: A polarizing optical system (15, 16) is disposed perpendicular to an optical axis of incoming light from a light source (12), having the optical axis (12) as a center axis, and configured for polarization of incoming light to a prescribed reference state, an electro-optical device (17) is disposed perpendicular to the optical axis, having the optical axis as a center axis, and adapted, as a voltage to be measured is imposed thereon, to respond to the imposed voltage by polarizing light polarized by the polarizing optical system (15, 16), and an analyzer (18) is disposed perpendicular to the optical axis, having the optical axis as a center axis, and adapted for detection of light polarized by the electro-optical device (17), to irradiate a detector (21) configured for conversion of incoming light into an electric signal.

Abstract: The present invention provides a photosensor that uses a phase modulation technique for optical detection and conducts a highly accurate measurement. The photosensor uses a phase change difference of light propagated through a polarization preserving fiber with respect to tensile stress and employs proper polarization preserving fibers for a phase modulator 10, light-transmitting polarization preserving fiber 23, and coil-shaped polarization preserving fiber 30, to achieve a highly accurate measurement.

Abstract: An optical voltage transformer is connected with an external electric device and includes a primary electrode to which a measured voltage is applied by the external electric device, a first secondary electrode provided oppositely to the primary electrode, an insulation layer provided between the primary and first secondary electrodes and constituting an insulation cylinder integrally formed with the primary and first secondary electrodes, a ground layer provided on an outer circumference of the insulation cylinder and around the first secondary electrode for securing a capacitance by interposing the insulation layer between the ground layer and the first secondary electrode, and an electro-optic element for measuring a voltage between the first secondary electrode and the ground layer.

Abstract: A polarizing optical system (15, 16) is disposed perpendicular to an optical axis of incoming light from a light source (12), having the optical axis (12) as a center axis, and configured for polarization of incoming light to a prescribed reference state, an electro-optical device (17) is disposed perpendicular to the optical axis, having the optical axis as a center axis, and adapted, as a voltage to be measured is imposed thereon, to respond to the imposed voltage by polarizing light polarized by the polarizing optical system (15, 16), and an analyzer (18) is disposed perpendicular to the optical axis, having the optical axis as a center axis, and adapted for detection of light polarized by the electro-optical device (17), to irradiate a detector (21) configured for conversion of incoming light into an electric signal.

Abstract: The present invention provides a photosensor that uses a phase modulation technique for optical detection and conducts a highly accurate measurement. The photosensor uses a phase change difference of light propagated through a polarization preserving fiber with respect to tensile stress and employs proper polarization preserving fibers for a phase modulator 10, light-transmitting polarization preserving fiber 23, and coil-shaped polarization preserving fiber 30, to achieve a highly accurate measurement.

Abstract: An optical voltage transformer is connected with an external electric device and includes a primary electrode to which a measured voltage is applied by the external electric device, a first secondary electrode provided oppositely to the primary electrode, an insulation layer provided between the primary and first secondary electrodes and constituting an insulation cylinder integrally formed with the primary and first secondary electrodes, a ground layer provided on an outer circumference of the insulation cylinder and around the first secondary electrode for securing a capacitance by interposing the insulation layer between the ground layer and the first secondary electrode, and an electro-optic element for measuring a voltage between the first secondary electrode and the ground layer.

Abstract: A power control device includes an electric power storage device connected across a power supply line for a load and including at least one electric double layer capacitor (EDLC) bank and a secondary battery combined with the EDLC bank, the EDLC bank including a plurality of parallel-connected rows of EDLC unit cells, each of the rows including a plurality of series-connected EDLC unit cells, and a control device controlling the electric power storage device so that when an input power to the electric power storage device is interrupted, the EDLC bank supplies electric power to the load for an initial period of the power interrupt and subsequently, the secondary battery supplies electric power to the load.

Abstract: An electrical double-layer capacitor has a construction wherein a pair of positive and negative polarizing electrodes whose chief constituent is active carbon laminated (or coiled) in a condition with a separator sandwiched therebetween and with their outsides held by respective aluminum collection electrodes are accommodated in a case made of metal etc. in a condition impregnated with electrolyte using propylene carbonate as solvent. The polarizing electrodes have a solid-state structure wherein the active carbon particles are the chief constituent (first substance) and these active carbon particles 3 are connected in network fashion by a second substance such as for example nano-size carbon black which is of higher electrical conductivity than the active carbon and of smaller size than the active carbon particles.

Abstract: A power control device includes an electric power storage device connected across a power supply line for a load. The electric power storage device includes an electric double layer capacitor (EDLC) bank including a plurality of parallel-connected rows of EDLC unit cells, each of which rows includes a plurality of series-connected EDLC unit cells.

Abstract: In a method of diagnosing aged degradation of an oil-filled electrical equipment such as oil-filled power transformers, an amount of organic compounds, other than a combustible gas, dissolved in an insulation oil employed in the equipment is detected. The degree of aged degradation of the equipment is determined based on a result of detection of the amount of organic compounds.

Abstract: A partial discharge detecting device for transformers includes an antenna disposed in a metallic insulation gas filled tank enclosing a core and coil assembly and a signal processing circuit for processing an output signal from the antenna. The antenna includes a magnetic core and a single coil or two coils differently operated. An electromagnetic wave due to the partial discharge is detected by the antenna. A detection signal from the antenna is supplied to the signal processing circuit, which determines whether or not the partial discharge has taken place, based on the detection signal.