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Traveling wave based relay protection

  • US 7,535,233 B2
  • Filed: 07/15/2004
  • Issued: 05/19/2009
  • Est. Priority Date: 07/15/2004
  • Status: Expired due to Fees
First Claim
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1. An apparatus comprising:

  • at least one Rogowski coil positioned on an electrical power transmission line within an AC electrical power distribution network that operates at a fundamental power frequency, the Rogowski coil;

    generates a first signal in which a first traveling wave current is filtered from a current component corresponding to the fundamental power frequency by sensing a change in current in the electrical power transmission line, wherein the first traveling wave current results from a fault on the electrical power transmission line of the network and a value of the first signal is proportional to the change in current, andgenerates a second signal in which a second traveling wave current is filtered from the current component corresponding to the fundamental power frequency by sensing a change in current in the electrical power transmission line, wherein the second traveling wave current results from the fault on the electrical power transmission line and a value of the second signal is proportional to the change in current; and

    a processor;

    receives the first signal and the second signal,compares the value of the first signal and the value of the second signal to a threshold value,if one or more of the value of the first signal and the value of the second signal exceeds the threshold value, determines a time difference between the first signal and the second signal, anddetermines, based on the time difference, where on the line the fault occurred relative to a location of a reference impedance mismatch.

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