A power converter with an inverter that is configured to transform electrical power between a DC-side of the power converter and an AC-side of the power converter, includes a first port operatively connected to an AC-grid, a second port operatively connected to an AC-load, a third port connected to an external power source, and a fourth port operatively connected to a rechargeable DC-power storage. The power converter includes a DC/DC-converter between the third port and the inverter, to transfer electrical power provided by the external power source from the third port to the inverter. The inverter is configured to be grid forming and provide electrical power to the second port upon a power supply outage at the first port, the power converter includes a control unit to monitor the third port and detect parameters of the electrical power provided via the third port.