MONITORING ARRANGEMENT

A monitoring arrangement for monitoring a parameter value associated with an AC supply or an AC component of a supply in a distribution network. The monitoring arrangement includes a sensor arrangement electrically connected, in use, to the network or otherwise monitoring the network, and a control unit operable to use the output of the sensor arrangement to determine, for a voltage, an amplitude value for a selected frequency. The method allows the operation of the device to be controlled depending on the supply from the network, without relying on signal components from rotating power converters.