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Ultra-high speed protective relay apparatus and method for providing single pole switching

  • US 4,438,475 A
  • Filed: 08/02/1982
  • Issued: 03/20/1984
  • Est. Priority Date: 08/02/1982
  • Status: Expired due to Fees
First Claim
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1. A protective relay for determining the location of a fault on the conductors of a three-phase ac electrical transmission line, comprising:

  • means for providing first, second, and third incident-wave signals representative of the current produced on each conductor by a fault-launched incident traveling wave arriving at the relaying point from a first direction;

    means for providing first, second, and third forward-wave signals representative of the current produced on each conductor by a fault-launched forward traveling wave arriving at the relaying point from a second direction;

    comparator means for comparing said first, second, and third incident-wave signals with, respectively, said first, second, and third forward-wave signals to provide an indication of the direction to the fault and to provide an enable signal when the fault is in said first direction;

    first filter means for filtering said first, second, and third incident-wave signals to provide a modal signal representing the total current produced on the transmission line by a first propagational mode of said first incident traveling wave; and

    discriminator means for processing said first, second, and third incident-wave signals, said modal signal, and said enable signal to provide an indication of the location of the fault.

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