An intelligent electrical power network control and/or protection device comprises at least one power supply connection for connecting the device to a main power source and an auxiliary power source and at least one unit configured to monitor main power, the unit being configured to activate a signal indicating lack of main power in response to lack of main power. The device further comprises at least one unit configured to provide a state control operation for changing an operating state of at least one unit of the device or an operating state of at least one unit to be connected to the device from an operative mode t a power saving mode in response to the activated signal indicating the detected lack of main power.