Mitsubishi Denki Kabushiki Kaisha

Tmt & D Corporation

Hirohide Aoki

Hiroyuki Hama

Yasuhiro Maeda

Yoshinori Shimizu

Mitsuo Matsumoto

Hiroshi Doi

Kiyoshi Inami

Naoyuki Kajita

Kuniaki Nakashima

Yoshikatsu Honda

Takuya Ootsuka

Kouichi Oosumi

A compact and economical gas-insulated switchgear is provided. The gas-insulated switchgear includes: a grounding metal housing filled with insulating gas, and in which the disconnector part having a moving side electrode part and a stationary side electrode part is accommodated; and composite insulating shields integrally formed into one metal-dielectric member in which surface of a high electric field part located in the vicinity of ends of openings is coated with a dielectric so as to cover the moving side and stationary side electrode parts and with the dielectric. To form the composite insulating shields , a metal shield of less than 0.6 in non-uniform constant before coating with the dielectric is coated with dielectrics having a thickness of not more than approximately 30% of an inter-electrode distance from a facing electric-field relaxation shield.

Gas-insulated switchgear

Disclosed is a transformer for a gas insulated electrical apparatus which requires no grounding field and which provides high accuracy with a simple structure. A transformer includes a capacitor type voltage divider having a floating electrode at a position opposed to a high-voltage conductor through an insulation sealing terminal mounted to a flange of a branch pipe provided on an inner surface of the annular grounding container; an ohm resistor for voltage division which has an impedance that is sufficiently smaller than the impedance between the floating electrode and the annular grounding container; and a converting portion which converts the detection voltage of the high-voltage conductor to a voltage value that allows processing on the secondary side.

Transformer for gas insulated electric apparatus

In a three-phase current transformer, a plate adaptor includes first to third coil insertion slots and is a magnetic shield. First to third Rogowskii coils are arranged in the first to third coil insertion slots. The metal adaptor is fixed with a phase-to-phase magnetic shield and an outer peripheral magnetic shield. An end magnetic shield is fixed to an end portion of the phase-to-phase magnetic shield.

Three-phase current transformer

A failure determining apparatus for a gas-insulated electrical appliance where the appliance is a cylindrical metal container with a charged conductor, insulating gas, and a plurality of insulating spaces inside for supporting the conductor and partitioning the container. The failure determining apparatus has a high-speed developing sensor which detects a high-speed phenomenon caused by a failure within the gas sections; a first failure determining circuit which determines the presence of a failure from an output of the high-speed developing sensor; a low-speed developing sensor which detects a low-speed phenomenon caused by a failure within the gas sections; a second failure determining circuit which determines the presence of a failure from an output of the low-speed developing sensor; and an arithmetic control circuit which identifies a gas section of the metal container in which a failure occurs from an output of the first and second failure determining circuits.

Failure determining apparatus of gas-insulated electrical appliance

A gas insulated switching device including a series of pressure containers and mutually connected, in which a conductor is positioned in an inside center, and an insulating and arc-extinguishing gas is filled in a space around the conductor , and a current transformer fabricated by Rogowskii coils for detecting a current passing through the conductor , the current transformer is attached to flanges of the pressure containers and via a metallic adaptor , wherein the current transformer is accommodated in a groove formed toward an inside of the metallic adaptor and uses the metallic adaptor to obtain an earth potential, whereby the gas insulated switching device having the current transformer with high accuracy can be miniaturized.

Growing community of inventors

Tokyo, Japan

Hirohide Aoki