Patent ID: 7450362
Filing Date: 2008-11-11
Classification: H01H

Abstract:
1. A method for disconnection of a fault current (I) which has occurred in an AC power supply system, comprising: supplying a disconnection command, which is produced in a protective device, to a synchronization controller to open a circuit breaker; delaying the disconnecting command in the synchronization controller until the circuit breaker can be opened in synchronism with the AC power supply system; monitoring the disconnection command emitted from the protective device and monitoring fault current, or a status signal emitted from the circuit breaker, and forming a first emergency disconnection command which acts on the circuit breaker if the fault current or the status signal is still present following a first delay time after the supplying of the disconnection command, which first delay time is greater than a sum of a natural response time of the circuit breaker and a time for quenching of a switching arc produced on opening of the circuit breaker.