Abstract: A three-dimensional surface potential distribution measurement system for measuring a surface potential of a measurement object comprises: a laser light source; a Pockels crystal exhibiting Pockels effect in which a refractive index changes depending on potential difference between the first end surface and the second end surface; a mirror disposed so as to be attached stationarily to the second end surface of the Pockels crystal; a photodetector to detect a light intensity of the laser light corresponding to the potential difference of the Pockels crystal; a housing that holds those elements; a three-dimensional motion-driver capable of three-dimensionally moving the housing; and a driving controller that controls the three-dimensional motion-driver.

Abstract: A three-dimensional surface potential distribution measurement system for measuring a surface potential of a measurement object comprises: a laser light source; a Pockels crystal exhibiting Pockels effect in which a refractive index changes depending on potential difference between the first end surface and the second end surface; a mirror disposed so as to be attached stationarily to the second end surface of the Pockels crystal; a photodetector to detect a light intensity of the laser light corresponding to the potential difference of the Pockels crystal; a housing that holds those elements; a three-dimensional motion-driver capable of three-dimensionally moving the housing; and a driving controller that controls the three-dimensional motion-driver.

Abstract: A three-dimensional surface potential distribution measurement apparatus includes: a laser light source; a Pockels crystal; a mirror; a light detector; a support structure which supports the aforementioned elements while maintaining a relative positional relationship therebetween; a movement driver which can move the support structure three-dimensionally; a rotary driver which supports the test object and can rotate the test object about an axis extending in a longitudinal direction of the test object; and a drive controller which controls the movement driver and the rotary driver. The drive controller coordinates a driving operation by the movement driver and by the rotary driver while maintaining a gap between the second end face of the Pockels crystal and a surface of the test object at a predetermined value such that the second end face of the Pockels crystal approaches all the surfaces of the electric field reduction system on the test object.

Abstract: A surface-potential distribution measuring device includes: a laser light source; a Pockels crystal; a mirror; a photodetector that detects light intensity of the laser beam reflected by the mirror; a holding and mounting part that holds and moves the Pockels crystal; a voltage correction database; and a calculation unit that identifies an input voltage corresponding to a testing output voltage as a surface potential of the electric-field-reduction system. The Pockels crystal is formed in such a way that a size of a cross section of the Pockels crystal that is perpendicular to an axial direction changes along the axial direction. The holding and mounting part has a protection unit to protect a structure of the Pockels crystal, a movement unit to that moves the Pockels crystal in order to measure a surface potential of the electric-field-reduction system, and a drive control unit to control the movement unit.

Abstract: In a surface potential distribution measuring device for an electric field reduction system of a rotating electrical machine, a Pockels crystal is used between a laser and the surface (test location) of the electric field reduction system. Light intensity of a laser beam reflected on a mirror provided between the Pockels crystal and the test location corresponds to an output voltage that is the voltage difference between the first end surface and the second end surface of the Pockels crystal. Even when an inverter voltage is generated, by using a light detector having a frequency band capable of following the high frequency components of the inverter pulse voltage, the light intensity is detected by the light detector. Therefore, from the light intensity (output voltage), the surface potential distribution measuring device can measure the surface potential of the electric field reduction system in which an inverter pulse voltage is generated.

Abstract: A three-dimensional surface potential distribution measurement apparatus includes: a laser light source; a Pockels crystal; a mirror; a light detector; a support structure which supports the aforementioned elements while maintaining a relative positional relationship therebetween; a movement driver which can move the support structure three-dimensionally; a rotary driver which supports the test object and can rotate the test object about an axis extending in a longitudinal direction of the test object; and a drive controller which controls the movement driver and the rotary driver. The drive controller coordinates a driving operation by the movement driver and by the rotary driver while maintaining a gap between the second end face of the Pockels crystal and a surface of the test object at a predetermined value such that the second end face of the Pockels crystal approaches all the surfaces of the electric field reduction system on the test object.

Abstract: A surface-potential distribution measuring device includes: a laser light source; a Pockels crystal; a mirror; a photodetector that detects light intensity of the laser beam reflected by the mirror; a holding and mounting part that holds and moves the Pockels crystal; a voltage correction database; and a calculation unit that identifies an input voltage corresponding to a testing output voltage as a surface potential of the electric-field-reduction system. The Pockels crystal is formed in such a way that a size of a cross section of the Pockels crystal that is perpendicular to an axial direction changes along the axial direction. The holding and mounting part has a protection unit to protect a structure of the Pockels crystal, a movement unit to that moves the Pockels crystal in order to measure a surface potential of the electric-field-reduction system, and a drive control unit to control the movement unit.

Abstract: In a surface potential distribution measuring device for an electric field reduction system of a rotating electrical machine, a Pockels crystal is used between a laser and the surface (test location) of the electric field reduction system. Thus, the light Light intensity of a laser beam reflected on a mirror provided between the Pockels crystal and the test location corresponds to an output voltage that is the voltage difference between the first end surface and the second end surface of the Pockels crystal. Even when an inverter voltage is generated, by using a light detector having a frequency band capable of following the high frequency components of the inverter pulse voltage, the light intensity is detected by the light detector. Therefore, from the light intensity (output voltage), the surface potential distribution measuring device can measure the surface potential of the electric field reduction system in which an inverter pulse voltage is generated.

Abstract: A resistance-provided UHV breaker includes a tank, a main contact unit, a resistance unit, and a resistance contact unit. The main contact unit includes plural main contacts arranged in the axial direction of the tank. The resistance unit includes plural resistances arranged in the axial direction of the tank. The resistance contact unit cooperates with the resistance unit to form a resistant parallel circuit and it is arranged, crossing the axial direction of the tank. The main and resistance contact units are opened and closed by an operating mechanism arranged outside the tank.

Abstract: A resistor-provided UHV breaker includes a tank, a main contact unit, a resistor unit, a resistor contact unit, support members, and a displacement absorbing system. The support members are arranged between the main contact and the resistor unit to support the resistor unit relative to the main contact unit. The displacement absorbing system is arranged at both ends of the resistor unit to absorb the relative displacement of the resistor unit in its axial direction.

Abstract: A superconducting current limiting apparatus includes a first container, a superconducting current limiting element accommodated in the first container, a refrigerant filling the first container for cooling the superconducting current limiting element accommodated in the first container, a second container for accommodating the first container in such a manner that the first container is heat insulated, and a conductor for connecting the superconducting current limiting element to an external power supply system. Such a superconducting current limiting apparatus can be used to limit a short-circuit current. It can be incorporated in a short circuit controlling superconducting system.

Abstract: A puffer type gas insulated circuit breaker has releasably engaging stationary and movable arc contacts contained in a vessel filled with an arc extinguishing gas. An operation rod serving as a supporting member of the movable arc contacts has openings and helps define a puffer chamber. In the breaker, gas is pressurized by an arc generated between said stationary arc contacts and said movable arc contacts in an initial breaking phase, this gas being taken into the puffer chamber. The holes are used as a heat exhaust passage.

Abstract: A puffer type gas-blast circuit breaker provided with a movable electrode and a fixed electrode opposite the movable electrode, which electrodes are separable for implementing a circuit-breaking action, and a fixed current-carrying contact arranged around the periphery of the fixed electrode. The movable electrode is equipped with a surrounding insulating nozzle having a tapered inside surface. Movement of the movable electrode during separation of the electrodes compresses the gas in a puffer chamber and so blows out the resulting arc between the movable and fixed electrodes. The circuit breaker further includes a cylindrical insulator or capacitor that surrounds the arc extinction chamber formed by the electrodes and the insulating nozzle between the movable and fixed electrodes.

Abstract: A DC interrupter unit as provided between a DC power source unit and a load unit. The DC interrupter unit includes a DC interrupter section having at least one interrupter to interrupt a DC current and a saturable reactor connected between the interrupter section and one terminal of the load unit. The interrupter unit further includes a series circuit having a resistor and capacitor in series, the series circuit being connected between the junction of the interrupter section and the saturable reactor and the other terminal of the load unit.

Abstract: A direct current interrupter comprising a plurality of two-point interrupter units each including a pair of interrupting portions. The interrupting portions of the interrupter units are arranged at regular angular intervals on a circle with the axial line of the interrupter as its center and arranged parallel to the axial line. An input terminal is provided to supply shunted current to one interrupting portion of each interrupter unit. An output terminal is provided to receive the shunted current from the other interrupting portion of each interrupter unit. A first common connecting portion and a second common connecting portion near the axial line. The main current flows through a conductor line from the main current input terminal to the first common connecting portion and shunted.

Abstract: Circuit interrupting apparatus for interrupting large direct currents comprising a plurality of parallelly connected branch circuits each including a circuit breaker and a saturable reactor connected in series therewith, and a commutating circuit including a capacitor. When opening the circuit breakers the commutating circuit is connected across the branch circuits to pass commutating current in the direction opposite to the normal load current. When the current decreases below a predetermined value, the saturable reactors desaturate to efficiently interrupt the load current.