Patent ID: 7457088
Filing Date: 2008-11-25
Classification: H02J

Abstract:
1. A power swing detection system for use in conjunction with blocking at least one relay from operating in an electrical network, comprising: a swing center voltage slope detector designed to detect an occurrence of a power swing within the electrical network based upon a time rate change of a swing center voltage value for the electrical network; a swing signature detector operatively connected to said swing center voltage slope detector designed to distinguish between an occurrence of a power swing within the electrical network and an occurrence of a fault within the electrical network, said swing signature detector designed to detect the occurrence of a power swing within the electrical network under circumstances wherein the swing center voltage slope detector does not detect the occurrence of said power swing, said swing signature detector designed to detect an occurrence of a power swing within the electrical network based upon a time rate of change of a swing center voltage value for the electrical network; and a dependable power swing detector operatively connected to said swing center voltage slope detector and said swing signature detector designed to detect an occurrence of a power swing within the electrical network when conditions exist within said electrical network that would not permit said swing center voltage slope detector and said swing signature detector to detect said occurrence of said power swing within a predetermined period of time, said dependable power swing detector, upon detection of said occurrence of said power swing, asserting a temporary signal for a predetermined period of time to permit said swing center voltage slope detector to detect said occurrence of said power swing and thereby compensating for a pickup delay of said swing center voltage slope detector.