Patents by Inventor Yutaka Kokai

Yutaka Kokai has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11916394
    Abstract: Provided are an operation limit value management unit managing an operation limit value related to the power flow power of system equipment and a determination unit calculating the power flow state for each set time of the future of a power system based on load dispatching information including a power generation plan value, a predicted output value, and a predicted value of power demand and determining whether or not stable is each power flow state by comparison with the operation limit value. The determination unit sequentially changes the first output power of a first power source defined by the power generation plan value of the first power source and calculates each power flow state based on power including the changed first output power and a predicted value of the output of a second power source.
    Type: Grant
    Filed: September 1, 2020
    Date of Patent: February 27, 2024
    Assignee: HITACHI, LTD.
    Inventors: Yutaka Kokai, Eisuke Kuroda, Kunihiko Tsunedomi
  • Publication number: 20230012079
    Abstract: Provided are an operation limit value management unit managing an operation limit value related to the power flow power of system equipment and a determination unit calculating the power flow state for each set time of the future of a power system based on load dispatching information including a power generation plan value, a predicted output value, and a predicted value of power demand and determining whether or not stable is each power flow state by comparison with the operation limit value. The determination unit sequentially changes the first output power of a first power source defined by the power generation plan value of the first power source and calculates each power flow state based on power including the changed first output power and a predicted value of the output of a second power source.
    Type: Application
    Filed: September 1, 2020
    Publication date: January 12, 2023
    Inventors: Yutaka KOKAI, Eisuke KURODA, Kunihiko TSUNEDOMI
  • Patent number: 11404873
    Abstract: This power system operation assisting device is provided with: a multiple signal frequency specifying unit that uses, as inputs, measured data of an object to be measured and a frequency specifying parameter for calculating a frequency component of the measured data to calculate an oscillation frequency; a generation source candidate calculation unit that uses, as an input, the calculated oscillation frequency to calculate a generation source candidate of an unstable oscillation occurring in a power system; a generation source guarantee test unit that calculates the guarantee test result of the generation source candidate; and a display unit that displays the oscillation frequency, the generation source candidate, and the guarantee test result.
    Type: Grant
    Filed: March 11, 2019
    Date of Patent: August 2, 2022
    Assignee: HITACHI, LTD.
    Inventors: Kenta Kirihara, Akira Tsubota, Yutaka Kokai, Sumito Tobe, Masahiro Yatsu, Hiroo Horii
  • Publication number: 20210126453
    Abstract: This power system operation assisting device is provided with: a multiple signal frequency specifying unit that uses, as inputs, measured data of an object to be measured and a frequency specifying parameter for calculating a frequency component of the measured data to calculate an oscillation frequency; a generation source candidate calculation unit that uses, as an input, the calculated oscillation frequency to calculate a generation source candidate of an unstable oscillation occurring in a power system; a generation source guarantee test unit that calculates the guarantee test result of the generation source candidate; and a display unit that displays the oscillation frequency, the generation source candidate, and the guarantee test result.
    Type: Application
    Filed: March 11, 2019
    Publication date: April 29, 2021
    Inventors: Kenta KIRIHARA, Akira TSUBOTA, Yutaka KOKAI, Sumito TOBE, Masahiro YATSU, Hiroo HORII
  • Publication number: 20020019762
    Abstract: An electric power demand prediction service method and a system therefor may derive an estimated value and/or predicted value of electric power demand of an arbitrary customer group and provide the derived information to electric power suppliers.
    Type: Application
    Filed: March 19, 2001
    Publication date: February 14, 2002
    Inventors: Yasushi Tomita, Yasushi Harada, Harumi Uchigasaki, Chihiro Fukui, Yutaka Kokai, Hiroshi Inoue, Nobuhisa Kobayashi
  • Publication number: 20020010624
    Abstract: An advertisement providing method is capable of providing information from an advertiser by selecting information adapting to the customer in response to a demand for information from the customer from the customer, efficiently. The method comprises checking whether a customer on access has a contract for using the information, permitting access to the information when the customer holds contract for using the information, for permitting retrieval of information registered as advertisement information by an advertiser depending upon the demand of the customer, optionally demanding additional information to the advertiser, delivering resultant information to the customer, and performing billing process for the customer and/or advertiser depending upon access record and delivery record of the customer.
    Type: Application
    Filed: March 20, 2001
    Publication date: January 24, 2002
    Inventors: Yasushi Tomita, Yasushi Harada, Harumi Uchigasaki, Chihiro Fukui, Yutaka Kokai, Nobuhisa Kobayashi
  • Patent number: 5553003
    Abstract: In a control system equipped with a plurality of subsystems and a supervising subsystem for supervising these subsystems, a subgoal achievement performance is calculated by the subsystem using its own knowledge and its own condition with respect to a subgoal defined by the supervising subsystem, and the supervising subsystem controls a control system by utilizing the knowledge and conditions of the respective subsystems by applying a subgoal execution instruction to the subsystem based upon the calculation result. Since not only the knowledge but also the condition of the subsystems, proper controls can be realized in not only such a case that the supervising goal is directed to a static temporal aspect, but also such a case that the supervising goal contains a temporal element.
    Type: Grant
    Filed: March 11, 1993
    Date of Patent: September 3, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Yasushi Harada, Yasunori Katayama, Junzo Kawakami, Tadayoshi Saitou, Chihiro Fukui, Yutaka Kokai, Shigeru Tamura