Patent ID: 8207742
Filing Date: 2012-06-26
Classification: H02H

Abstract:
1. A method of operating a circuit breaker in an electric circuit, said method comprising: identifying a first circuit breaker as a reference circuit breaker; determining when said identified reference circuit breaker is in reverse current pick-up; and when not, determining when a second circuit breaker is in short-time pick-up, indicative of a fault on the electric circuit; and when not; comparing a third direction of current flow through a third circuit breaker with a first direction of current flow through said identified reference circuit breaker; determining if said third circuit breaker is carrying current in a forward direction with respect to said identified reference circuit breaker and when said third circuit breaker is not in short-time pick-up, executing the steps of: when the first circuit breaker other than said identified reference circuit breaker is not in reverse current pick-up executing the steps of: increasing by a predetermined amount a trip time delay of said first and said second circuit breaker upstream of said third circuit breaker.