Patent ID: 6137666
Filing Date: 2000-10-24
Classification: H02H

Abstract:
A protective distance relay including signal processing circuitry, said protective relay capable of detecting abnormal line conditions in power transmission systems for the purpose of providing protection to said systems, said protective relay comprising:a. a signal generator processing system executed by said signal processing circuitry, said signal generator processing system determining an operate signal and a restraint signal by processing digitized versions of line current and voltage signals detected by the protective relay;b. a magnitude comparator processing system executed by said signal processing circuitry, said magnitude comparator system determining a trip condition signal by processing which includes comparing the magnitudes of said operate signal and said restraint signal, said trip condition signal representing the difference between said magnitudes; andc. a trip initiator system executed by said signal processing circuitry, said trip initiator system determining whether a trip command signal is initiated depending on the sign and magnitude of said trip condition signal.