Patents by Inventor Tokio Yamagiwa

Tokio Yamagiwa 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: 6538877
    Abstract: To provide a gas insulation switch reducing the SF6 gas use amount without damaging the insulation performance and arc extinguishing performance, the present invention uses SF6 gas as insulating gas to be charged in the grounding tank 1 of a unit having a switching unit of the breaker 5, the disconnecting switches 3, 4, and 8, and the grounding switches 6, 7; and 9, for example, the line unit 190 and uses gas having a smaller warming coefficient than that of SF6 gas, for example, nitrogen gas 23, or air as insulating gas to be charged in the grounding tank 1 of a unit having no switching unit, for example, the main bus units 100 and 110 and the connection bus unit 160.
    Type: Grant
    Filed: February 1, 2002
    Date of Patent: March 25, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Tokio Yamagiwa, Hiroki Honma, Koji Sasaki
  • Patent number: 6525917
    Abstract: This invention is to provide a transforming system capable of satisfactorily protecting the equipment of a substation even if a aerial electric power lines is struck directly by an intense electric shock of a large energy, such as an electric shock of a waveform similar to that of a thunderbolt stroke having a long duration of wave tail. So, this invention, a transforming system comprises, a lightning arrester, a ground fault device installed near a service entrance through which the power lines are led in, a voltammeter placed on the gas-insulated switchgear, and a control device receiving a signal from the voltammeter and providing a signal for controlling the grounding device. And when detecting of said thunderbolt arising in said aerial electric power line, a control device which order said ground fault device to make the ground fault condition.
    Type: Grant
    Filed: August 10, 1999
    Date of Patent: February 25, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Hiroshi Arita, Takahide Matsuo, Satoshi Watahiki, Shingo Shirakawa, Naoki Kasahara, Shinichi Kondo, Tokio Yamagiwa
  • Publication number: 20020163344
    Abstract: An insulated device diagnosing system capable of judging the deterioration, lifetime, defects and so on of a device highly sensitively and precisely.
    Type: Application
    Filed: July 2, 2002
    Publication date: November 7, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Toshiaki Rokunohe, Fumihiro Endo, Tokio Yamagiwa, Ryouichi Shinohara
  • Patent number: 6424162
    Abstract: An insulated device diagnosing system is capable of judging the deterioration, lifetime, and defects of a device. The intensity at each voltage phase angle is measured at a plurality of specific frequencies, taking high voltage phase angles as the abscissas. The deterioration, lifetime, and the kind and extent of abnormality of the device are judged from the pattern and intensity of the spectral distribution, which is obtained by peak-holding the measured intensity for a defined time period. According to the present invention, partial discharge can be measured highly sensitively and precisely to diagnose the deterioration, lifetime and the extent of defect of the device. As a result, the insulation reliability of the device can be improved, and the part of the device that should be repaired/replaced can be grasped before disassembly of the device, thereby cutting the maintenance cost.
    Type: Grant
    Filed: August 11, 1999
    Date of Patent: July 23, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Toshiaki Rokunohe, Fumihiro Endo, Tokio Yamagiwa, Ryouichi Shinohara
  • Publication number: 20020071242
    Abstract: To provide a gas insulation switch reducing the SF6 gas use amount without damaging the insulation performance and arc extinguishing performance, the present invention uses SF6 gas as insulating gas to be charged in the grounding tank 1 of a unit having a switching unit of the breaker 5, the disconnecting switches 3, 4, and 8, and the grounding switches 6, 7, and 9, for example, the line unit 190 and uses gas having a smaller warming coefficient than that of SF6 gas, for example, nitrogen gas 23, or air as insulating gas to be charged in the grounding tank 1 of a unit having no switching unit, for example, the main bus units 100 and 110 and the connection bus unit 160.
    Type: Application
    Filed: February 1, 2002
    Publication date: June 13, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Tokio Yamagiwa, Hiroki Honma, Koji Sasaki
  • Patent number: 6373687
    Abstract: To provide a gas insulation switch reducing the SF6 gas use amount without damaging the insulation performance and arc extinguishing performance, the present invention uses SF6 gas as insulating gas to be charged in the grounding tank 1 of a unit having a switching unit of the breaker 5, the disconnecting switches 3, 4, and 8, and the grounding switches 6, 7, and 9, for example, the line unit 190 and uses gas having a smaller warming coefficient than that of SF6 gas, for example, nitrogen gas 23, or air as insulating gas to be charged in the grounding tank 1 of a unit having no switching unit, for example, the main bus units 100 and 110 and the connection bus unit 160.
    Type: Grant
    Filed: August 1, 2001
    Date of Patent: April 16, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Tokio Yamagiwa, Hiroki Honma, Koji Sasaki
  • Publication number: 20020008958
    Abstract: To provide a gas insulation switch reducing the SF6 gas use amount without damaging the insulation performance and arc extinguishing performance, the present invention uses SF6 gas as insulating gas to be charged in the grounding tank 1 of a unit having a switching unit of the breaker 5, the disconnecting switches 3, 4, and 8, and the grounding switches 6, 7, and 9, for example, the line unit 190 and uses gas having a smaller warming coefficient than that of SF6 gas, for example, nitrogen gas 23, or air as insulating gas to be charged in the grounding tank 1 of a unit having no switching unit, for example, the main bus units 100 and 110 and the connection bus unit 160.
    Type: Application
    Filed: August 1, 2001
    Publication date: January 24, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Tokio Yamagiwa, Hiroki Honma, Koji Sasaki
  • Patent number: 6292356
    Abstract: A gas insulation switch has a container charged with insulating gas which contains an electric conductor and at least a pair of contactors. The container is divided into a plurality of sections. For the sections which have no switching devices or separable contactors, a different insulating gas is used as compared with that for the sections having breakers or separable contactors. In particular, in the section of the container, such as a grounding tank, that contains only electric conductors without separable contactors, an insulating gas having a smaller earth warming coefficient or global warming coefficient than that of SF6 gases is used. On the other hand, for the section of the grounding tank which contains a breaker or switch having separable contactors, an SF6 insulating gas is used.
    Type: Grant
    Filed: March 22, 1999
    Date of Patent: September 18, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Tokio Yamagiwa, Hiroki Honma, Koji Sasaki
  • Patent number: 6252763
    Abstract: A gas-insulated electrical apparatus includes tanks into each of which insulation gas is sealed, including bus-bars, bus-bar disconnectors connected to the bus-bars, circuit breakers connected to the bus-bar disconnectors, and line disconnectors connected to the circuit breakers, each line disconnector being further connected to a transmission or a transformer; wherein each bus-bar disconnector and each line disconnector include a respective pair of a fixed-contact and a moving-contact, the fixed-contact and the moving-contact being concave and convex, respectively, and each of the moving-contacts in the bus-bar disconnector and the line disconnector is located at the side of a corresponding circuit breaker between the bus-bar disconnector and the line disconnector, a contact-parting speed in the line connector being lower than that in the bus-bar disconnector.
    Type: Grant
    Filed: November 5, 1999
    Date of Patent: June 26, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Yoshikatsu Enokida, Tokio Yamagiwa, Kenji Annou, Manabu Takamoto, Hirohiko Yatsuzuka, Masahiro Shimokawa
  • Patent number: 6218627
    Abstract: A bushing has a central conductor, and a plurality of internal shield rings. Gaps are formed between the shield rings such that equipotential lines extend through gaps. Electric field concentration in a tangential distribution on a part of the surface of the bushing corresponding to an upper part of an internal shield ring is relieved to prevent corona discharge under wet conditions, and antipollution performance and withstand voltage characteristics can be improved.
    Type: Grant
    Filed: February 2, 1999
    Date of Patent: April 17, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Katsuji Shindo, Toshiaki Rokunohe, Fumihiro Endo, Tokio Yamagiwa
  • Patent number: 6063997
    Abstract: In a gas insulated electric apparatus having gas sections filled with insulating gas, a locating device determines a position of a gas section in which an insulation abnormality is detected, on the basis of a detection signal from sensors disposed in each of predetermined gas sections. At the same time a hindering degree diagnosing device diagnoses the degree and the kind of the insulation abnormality, by comparing a detection signal from the sensors with data stored in a data base. A valve control generates a valve control signal, responding to the locating device and the hindering degree diagnosing device, and in response to the valve control signal, a trip circuit generates a valve opening signal to open an electromagnetic valve disposed in a gas section in which an insulation abnormality is detected.
    Type: Grant
    Filed: August 15, 1994
    Date of Patent: May 16, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Fumihiro Endo, Tomoaki Utsumi, Toshio Ishikawa, Shuzo Iwaasa, Tokio Yamagiwa
  • Patent number: 6002085
    Abstract: A gas insulated switchgear has a container which is filled with an insulating gas, a conductor disposed with the container, an insulator for supporting the conductor. An outer periphery of the insulator is made smooth so as to improve a dielectric strength of the device. The insulator is made of an organic substance base and an inorganic material filler added to the base. In order to improve the dielectric strength, the filler is atomised or the insulator is coated.
    Type: Grant
    Filed: December 8, 1994
    Date of Patent: December 14, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Tomoaki Utsumi, Toshio Ishikawa, Shuzo Iwaasa, Fumihiro Endo, Tokio Yamagiwa
  • Patent number: 5982181
    Abstract: An insulated device diagnosing system is capable of judging the deterioration, lifetime, and defects of a device. The intensity at each voltage phase angle is measured at a plurality of specific frequencies, taking high voltage phase angles as the abscissas. The deterioration, lifetime, and the kind and extent of abnormality of the device are judged from the pattern and intensity of the spectral distribution, which is obtained by peak-holding the measured intensity for a defined time period. According to the present invention, partial discharge can be measured highly sensitively and precisely to diagnose the deterioration, lifetime and the extent of defect of the device. As a result, the insulation reliability of the device can be improved, and the part of the device that should be repaired/replaced can be grasped before disassembly of the device, thereby cutting the maintenance cost.
    Type: Grant
    Filed: December 8, 1997
    Date of Patent: November 9, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Toshiaki Rokunohe, Fumihiro Endo, Tokio Yamagiwa, Ryouichi Shinohara
  • Patent number: 5929989
    Abstract: Light from a light source is fed to a sensing probe through a polarization plane-reserving fiber, and is split into two light beams, that is, a reference beam and a measurement beam. The reference beam is passed through a reference medium, and the measurement beam is passed through a pressure-sensitive medium, which may be in the form of gas. Then, the reference beam and the measurement beam are fed to a light-receiving portion via the polarization plane-reserving fiber, and are converted into electrical signals. The electrical signals are inputted into a signal processing portion, and the optical path length difference between the reference and measurement beams, passed through their respective mediums, is determined, and the pressure of the pressure-sensitive medium is detected from this optical path length difference.
    Type: Grant
    Filed: May 1, 1996
    Date of Patent: July 27, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Sadao Mori, Toshio Akatsu, Tokio Yamagiwa
  • Patent number: 5798484
    Abstract: A gas filled electric conductor arrangement has an inclined surface (3A) at the bottom side of an electric conductor (3) that is formed by gradually reducing the cross section (D1, D2) of the electric conductor from one insulator spacer (2A) at one side toward another insulator spacer (2B) at the other side. Because of an angle (.theta.) of the inclined surface (3A), the spacing distance between the electric conductor (3) and the bottom surface (1A) of a grounded tank (1) increases depending upon the distance away from one insulator spacer (2A). Thereby, conductive foreign particles (50) are designed to be moved away from the surface of the insulator spacer (2A) and become trapped by a conductive foreign particle (1) disposed at the center bottom surface (1A) of the grounded tank.
    Type: Grant
    Filed: February 8, 1994
    Date of Patent: August 25, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Tokio Yamagiwa, Fumihiro Endo, Kazutoshi Asano
  • Patent number: 5699219
    Abstract: A ground fault current limiter, in which reactors are connected in series to a neutral point for compensating for capacitances to ground of a power switches capable of turning ON/OFF at a high speed are connected in parallel with respective reactors, occurrence of a ground fault is detected from a phase difference between a zero-phase sequence current and a zero-phase sequence voltage at time of sampling, an optimal compensation quantity of capacitances to ground is computed based on the zero-phase sequence current and the zero-phase sequence voltage at time of occurrence of a ground fault, and ON/OFF of the switches are controlled thereby to alter the reactor quantity so as to correspond to the compensation quantity.
    Type: Grant
    Filed: May 16, 1995
    Date of Patent: December 16, 1997
    Assignees: Hitachi, Ltd, Chubu Electric Power Co., Inc.
    Inventors: Hiroshi Arita, Junzo Kida, Yoshiaki Matsui, Tokio Yamagiwa, Shigeyuki Sugimoto, Sadanori Neo
  • Patent number: 5689088
    Abstract: A gas insulated device includes a grounded tank filled with an insulating gas and having a conical insulator spacer securely mounted therein to define an interior space. A through-type electric connector extends through and is supported by the insulated spacer and an electric conductor is electrically connected to the through-type electric conductor by a conductor connector. The conductor connector closest to the insulator spacer is positioned such that electric flux lines exiting from the conductor connector intersect with the surface of the insulator spacer in a region in which an electric field has a strength equal to or less than 70% of the strength of the strongest electric field on the surface of the insulator spacer generated by a lightning impulse applied to the gas insulated device.
    Type: Grant
    Filed: December 19, 1995
    Date of Patent: November 18, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Toshiaki Rokunohe, Fumihiro Endo, Tokio Yamagiwa, Kenji Anno
  • Patent number: 5627941
    Abstract: The number of hidden layers is no larger than 2 and a sum is determined for each case. A relationship between the sum of the inputs and teaching data for each case is expressed in a table in a descending order of the sum of inputs for each output of an output layer, and the teacher data for the maximum sum and the number of times of change in the teacher data are considered. A configuration (the number of hidden layers and the number of neurons thereof) is determined based on those data, and the coupling weights can be analytically calculated by using the table. Where the number of times of change of the teacher data is odd, some inputs do not route a second hidden layer.
    Type: Grant
    Filed: August 25, 1993
    Date of Patent: May 6, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Isao Takahashi, Fumihiro Endo, Tokio Yamagiwa
  • Patent number: 5601735
    Abstract: A laser welding device for welding a long sized tubular grounding unit includes a work head arranged to rotate around an outer circumference of two tubular members to be welded, a laser oscillator, and apparatus to transmit the laser beam from the oscillator in sychronism with rotation of the work head. In one embodiment the apparatus to transmit the laser beam includes an optical fiber.
    Type: Grant
    Filed: April 13, 1993
    Date of Patent: February 11, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Hideo Kawamoto, Tokio Yamagiwa, Shinji Fukuda, Masayoshi Hashiura, Osamu Isshiki, Shigetaka Takeuchi, Masaki Murashita
  • Patent number: 5598509
    Abstract: In a recognition/diagnosis method, a relation between total sums of inputs of respective cases and teacher data is listed in the order of magnitude of the total sums of inputs. Based on the value of the teacher data for the input having the maximum total sum and the number of times of change of teacher data in the table are considered, a configuration of a neural network (the number of hidden layers and the number of neurons thereof) is determined. Coupling weights are analytically calculated based on the table.
    Type: Grant
    Filed: March 18, 1994
    Date of Patent: January 28, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Isao Takahashi, Fumihiro Endo, Tokio Yamagiwa