Patents by Inventor Martin T. Bishop

Martin T. Bishop 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).

  • Protective relay apparatus for detecting high-impedance ground faults
    Patent number: 4600961
    Abstract: A protective relay for detecting high-impedance ground faults on a three-wire distribution system. The protective relay operates independently of the current in the ground path by using the positive and negative sequence currents to detect a fallen conductor. The ratio of the negative sequence to positive sequence current is calculated and when this ratio exceeds a predetermined value, a trip signal is produced.
    Type: Grant
    Filed: September 1, 1983
    Date of Patent: July 15, 1986
    Assignee: Westinghouse Electric Corp.
    Inventor: Martin T. Bishop
  • Protective relay
    Patent number: 4363066
    Abstract: A percent unbalance or ratio ground relay which detects open phase conductors on electrical distribution circuits, as well as single-phase-to-ground faults regardless of fault impedance, by providing an operating quantity responsive to zero sequence current, and a restraining quantity responsive to a pre-fault balanced phase current minus the zero sequence current. This restraint torque arrangement causes the relay to operate on true ratio unbalance, regardless of load.
    Type: Grant
    Filed: March 20, 1981
    Date of Patent: December 7, 1982
    Assignee: Westinghouse Electric Corp.
    Inventor: Martin T. Bishop