Method and apparatus for a network synchronized switching of a power switch

In addition to measuring current flowing through the power circuit breaker (9), and the voltage on one side, an additional voltage measurement is taken on the other side. All measured signals are fed into a controller (18). There, with stored data characterizing all possible switching cases, it is determined which measurement signal shall be taken as the reference value for operation of the power circuit breaker, in synchronism with the grid. A corresponding command is generated by the controller, and executed by the power circuit breaker. An Independent claim is included for corresponding equipment which includes an additional voltage transformer to make the measurement on the other side of the power circuit breaker.