Patents by Inventor Yoshifumi Oura

Yoshifumi Oura 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).

  • Transformer protection system
    Patent number: 4772978
    Abstract: In a transformer protection system, data of voltages and currents detected at individual terminals of a transformer connected to an electric power system are supplied to a computer. The computer computes driving point admittances or shunt admittances of the transformer on the basis of the voltage and current data and predetermined transfer admittances of the transformer and decides that an internal fault has occurred in the transformer when the values of the driving point admittances or shunt admittances deviate from pre-set reference values, thereby disconnecting the transformer from the electric power system.
    Type: Grant
    Filed: October 14, 1986
    Date of Patent: September 20, 1988
    Assignees: Hitachi, Ltd., The Tokyo Electric Power Co.
    Inventors: Yoshifumi Oura, Kunio Matsuzawa, Kazuyoshi Yoshida, Keizo Inagaki, Hiroyuki Kudo, Yoshihiro Sano