Patents by Inventor Daging Hou

Daging Hou 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).

  • Loss of potential determination for use in protective relays for electric power systems
    Patent number: 5883578
    Abstract: The positive sequence voltage on the power line is measured at a given time, i.e. the present time, and also for one cycle earlier, and the ratio thereof is then compared against a threshold value of 0.9. There are four other supervisory tests which also must be true for a loss of potential condition to be indicated. These include determination of change in positive sequence current and angle and zero sequence current and angle. If the change in those values is smaller than selected thresholds, then a loss of potential condition is indicated.
    Type: Grant
    Filed: July 26, 1996
    Date of Patent: March 16, 1999
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: Jeffrey B. Roberts, Daging Hou