Hitachi, Ltd.

Jun Nukaga

Li Lu

Tomohiro Moriyama

Akira Yamagishi

Satoshi Ichimura

Yasutomo Saito

Toshiaki Rokunohe

Makoto Hirose

Masato Suzuki

Hiroshi Morita

Kenji Tsuchiya

Shinji Fujita

Youichi Ohshita

Tomoaki Utsumi

Kohei Yamaguchi

Kenichi Kawamura

Goro Daimon

Yoshio Hamadate

Takahiro Nishimura

Hiroshi Miyao

Hideki Ogata

Hiroshi Yoshimoto

Hideyuki Kotsuji

Hirokazu Furui

Yoshiaki Seya

An insulating spacer and a gas insulation shutoff apparatus each having a high dielectric strength against adhesion of a metal foreign substance are provided without increasing size or complicating a shape of the insulating spacer. In an insulating spacer of a gas insulation shutoff apparatus including a grounded tank filled with an insulating gas, a high-voltage conductor provided within the grounded tank, and the insulating spacer supporting and fixing the high-voltage conductor within the grounded tank, the insulating spacer includes a conductor to be connected to the high-voltage conductor, an insulating structure supporting and fixing the conductor within the grounded tank, and a nonlinear resistance layer provided on a creepage surface of the insulating structure, and the nonlinear resistance layer is provided in a portion to be a high-field portion of the creepage surface of the insulating structure.

Insulation spacer and gas insulation shutoff apparatus using the insulation spacer

An object is to enhance direct-current insulating performance of a gas-blast circuit breaker. The gas-blast circuit breaker includes: a pair of main contacts disposed in a gas tank to face each other and configured to operate for opening and closing a circuit; a pair of arc contacts disposed to face each other and configured to operate for opening and closing the circuit, the arc contacts being disposed coaxially with the main contacts at locations close to the centers of the main contacts, respectively; and an elastic electrically conductive material disposed on an outer surface of an insulating nozzle facing an inner surface of one of the main contacts.

Gas-blast circuit breaker

An oil leakage detector of the present invention includes an image processing unit wherein the image processing unit calculates the values of saturation and intensity of each pixel in the color image of the object after an ultra-violet light is irradiated thereon, draws an intensity-saturation characteristic line of the saturation expressed in an X-axis and the intensity expressed in a Y-axis, sets an upper limit and a lower limit of intensity of each saturation as a threshold value based on an area without oil adhesion on the surface of the object, and determines, in the intensity-saturation characteristic line, an area corresponding to a pixel group where the intensity exceeds the threshold value of the upper limit and a pixel group where the intensity falls below the threshold value of the lower limit, to be an oil leakage adhered area.

Oil leakage detector and oil leakage detection method and image processing unit

A leakage oil detection system includes a measurement device including a light source that causes a measured object which includes a leakage oil attachment part to be irradiated with ultraviolet rays, and an imaging device that detects fluorescence emitted from the leakage oil attachment part which is irradiated with the ultraviolet rays, and performs imaging on the measured object; and an analysis device that includes a driving control unit that controls operations of the light source and the imaging device, a recording unit that records an imaged image of the measured object which is imaged by the imaging device, and an image processing unit that calls the imaged image which is recorded in the recording unit and performs an image process to detect leakage oil.

Leakage oil detection system

A system and method for detecting leakage oil with a high degree of accuracy while avoiding the complexity of the system and the influence of noise light comprise: ultraviolet light sources arranged to irradiate an oil-filled device from a plurality of different incidence angles, and are switched on and off at the respective incidence angles in sequence, and include a wavelength exciting oil; an imaging device to photograph the oil-filled device irradiated with ultraviolet light emitted from the ultraviolet light sources when the ultraviolet light sources are switched on; a recorder to record respective images photographed by the imaging device; and a display to display the respective images. The respective images are compared, a site where a light emitting position does not change always is judged as a leakage oil site, and a site emitting light or not emitting light occasionally is judged as a noise light site.

Leakage oil detector system and method

A stationary induction electrical apparatus includes a disc winding having a structure in which a flow path for a cooling medium is provided between coils where a low voltage is generated between shield wires, an L-shaped insulation barrier is provided between coils where a high voltage is generated between the shield wires, a horizontal portion of the L-shaped insulation barrier is provided so as to closely contact an upper surface or a lower surface of the disc coil, a tip end portion in an axial direction of the L-shaped insulation barrier is provided so as to closely contact an inner surface of the disc coil which is adjacent to a pressboard insulation cylinder, and a height of the tip end portion in the axial direction is lower than a thickness of one coil.

Stationary induction electrical apparatus

Oil leakage detector and oil leakage detection method

Disclosed is a power switch gear that includes: a fixed electrode and a movable electrode disposed opposite to each other in a tank filled with insulting gas; and a movable conductor electrically connecting the fixed electrode and the movable electrode together. The fixed electrode and the movable electrode have a contactor through which current flows to the movable conductor. At least one of the fixed electrode and the movable electrode has ring-shaped sliding members, the ring-shaped sliding members being disposed, on both sides of the contactor. At least one grease pool is provided between the contactor and the sliding members.

Power switchgear

The gas circuit breaker comprises a metal container filled with an insulating gas; first and second contacts disposed opposite each other in the metal container so that they can be brought into and out of engagement with each other; and a metal shield arranged in the metal container to enclose the two contacts. A part or a whole of the surface of the shield is oxidized and covered with a fluororesin layer. The gas circuit breaker with this construction can protect the shield surface against flaking and scores when subjected to mechanical impacts and can maintain high dielectric strength without increasing the size of the circuit breaker.

Gas circuit breaker

Growing community of inventors

Tokyo, Japan

Jun Nukaga