Hitachi, Ltd.

Shikoku Electric Power Co., Inc.

Shikoku Denryoku Kabushiki Kaisha

Shikoku Keisoku Kogyo Kabushiki Kaisha

Seiichi Sakai

Katuo Sugawara

Shigeo Shiono

Etsunori Mori

Hideo Tsukioka

Toshihiko Gange

Ichitaro Tani

Ictitaro Tani

Hamao Onishi

Masaru Ukawa

Osamu Masada

Masahide Takahashi

There is disclosed a photovoltaic power control system equipped with at least one inverter for inverting an output of a solar cell array to AC power, and having charge-and discharge control means for charging a surplus portion with respect to the power for expected use of the output of the solar cell array to a storage battery and discharging shortage portion with respect to the power for expected use of the output of the solar cell array from the storage battery by detecting the surplus or shortage produced between the output of the solar cell array and AC power for expected use inverted by the inverter, the improvement comprising weather fluctuation pattern selection means for selecting one weather pattern out of various kinds of weather patterns preset based on weather information at a time point when the weather is forecasted on the day when the power is generated by the solar cell array; and workable pattern selection means for selecting one actuation pattern of the inverter corresponding to the weather pattern selected by the weather fluctuation pattern selection means out of various actuation patterns of the inverter preset corresponding to the weather pattern.

Photovoltaic power control system

Method and apparatus for diagnosing abnormality of an oil-filled electric apparatus is disclosed. Presence or absence of abnormality is determined by comparing contents of plural predetermined components contained in gas extracted from the oil of the electric apparatus with respective predetermined reference values. The type of abnormality is determined on the basis of at least one set of two specific components selected from the plural components.

Method and apparatus for diagnosing oil-filled electric apparatus

In an apparatus for detecting gas components in the oil in an oil-filled device, which comprises a gas-storing chamber being provided at an oil-filled device containing an insulating oil through a gas-permeating material capable of separating gas components from the insulating oil, a gas calibration tube being provided at the gas-storing chamber through a switch valve, and a gas chromatographic device connected to the gas calibration tube through the switch valve, any influence of gas components in a subatmospheric pressure is eliminated and exact concentrations of gas components are detected by providing at least one stirring mixer having at least one throttle perforation in a carrier gas passage for supplying the gas components from the gas calibration tube to the gas chromatographic device at the upstream side of a gas separation column of the gas chromatographic device, or by proving a circulation passage between the gas-storing chamber and the gas calibration tube, a valve capable of being exposed to the atmosphere at the circulation passage, and a gas circulation unit at the circulation passage for circulating the gas in the circulation passage.

Method and apparatus for detecting gas components in oil in oil-filled

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Kagawa, Japan

Seiichi Sakai