A METHOD FOR ESTIMATING AN ELECTRICAL OPERATING TIME OF A CIRCUIT BREAKER USING CURRENT FEEDBACK

The present invention provides a method of determining an electrical operating time of a circuit breaker (140) in a multiphase electrical system having a subsystem (160) at an electric potential resulting from electrical characteristics of electrical components within the subsystem. The method comprises monitoring (145) the voltage of the subsystem in the first phase, determining a first rate of change from the monitored voltage in the first phase, detecting at least one instance of switching based on the first rate of change, determining an electrical operating time of the circuit breaker based on the detected at least one instance of switching and an instance at which a command for switching was provided to the circuit breaker.