Arrangement for monitoring a current network

Abstract

An arrangement for monitoring a current network to which is connected at least one self-excited or separately excited three-phase synchronous machine which is operatively connected e.g. to a device which is in immediate readiness for operation and comprises an energy storage device, while between the neutral or star point of the three-phase synchronous machine and the neutral wire of the network a monitoring device is arranged for controlling the network master switch. The monitoring device includes an M.sub.P -current converter, a load following the M.sub.P -converter and a frequency relay. The frequency relay ascertains the zero axis crossings of the dropping voltage on the load. The drop of the zero axis crossing frequency below a preset value serves as a signal for a network failure and for the actuation of the network switch and/or for other switch operations desired in this connection.

Dependencies are inferred from the claim text.