Mitsubishi Electric Corporation

Tatsuya Yabe

Chieko Nishida

Yoshiyuki Tamura

Manabu Yoshimura

Takashi Ito

A partial discharge detection apparatus detects a plurality of discharge events, finds a time interval between the plurality of discharge events, and determines, where the discharge events occur at a time interval shorter than a threshold time, that a partial discharge has occurred within a metal enclosure, or determines, where the discharge events occur only at a time interval longer than the threshold time, that a discharge has occurred outside the metal enclosure. The partial discharge detection apparatus can thus readily distinguish between a partial discharge that occurs within the metal enclosure of a gas-insulated switchgear and a discharge that occurs outside the metal enclosure.

Method and apparatus for detecting partial discharge within electrical equipment

A moisture concentration detecting device including a gas chamber; a pair of porous electrodes facing each other in the gas chamber; a solid electrolyte membrane sandwiched between the electrodes; a case which covers the electrodes and the solid electrolyte membrane and on a surface of which a pleated portion is provided; an impedance measuring circuit measuring an AC impedance between the electrodes by applying an AC voltage to the electrodes; a storage device storing therein conversion information for converting an AC impedance between the electrodes into a moisture concentration in the insulating gas; and a computing unit obtaining a moisture concentration in the insulating gas from a measured value of the AC impedance by referring to the conversion information stored in the storage device with respect to the measured value of the AC impedance input from the impedance measuring circuit.

Moisture concentration detecting device

The water-concentration detection device for detecting a water concentration of insulating gas filled in a gas-insulated device includes: porous electrodes having porous properties that are arranged to face each other in the insulating gas; a solid electrolyte membrane that is sandwiched between and fixedly attached to the electrodes and has hydrogen-ion conductivity; a voltage application unit that applies an alternating-current voltage at a frequency of 325 Hz or a frequency of 10 Hz or lower to the electrodes; an impedance measurement unit that measures an alternating-current impedance between the electrodes in a state in which the alternating-current voltage is applied to the electrodes; and a water-concentration detection unit that detects the water concentration of the insulating gas based on the alternating-current impedance measured by the impedance measurement unit.

Water-concentration detection device

A water-concentration detection device is configured to detect a water concentration of insulating gas filled in a gas-insulated device. The water-concentration detection device includes: a gas chamber in which the insulating gas introduced from the gas-insulated device is enclosed; electrodes that are porous and are arranged to face each other within the gas chamber; a solid electrolyte membrane that is hydrogen-ion conductive and is held between and fixedly attached to the electrodes; an impedance measurement unit that measures an alternating-current impedance between the electrodes by applying an alternating-current voltage to the electrodes; a water-concentration detection unit that detects the water concentration of the insulating gas based on the alternating-current impedance measured by the impedance measurement unit; and a drying unit that removes water from an atmosphere in the gas chamber before the insulating gas is introduced into the gas chamber from the gas-insulated device.

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Tokyo, Japan

Tatsuya Yabe