Determining the rating of a direct voltage source being connectable via an inverter and a power switch to an electricity network

摘要

The method involves controlling an inverter (4) such that the inverter converts DC input voltages (Uq, Uz) to a test frequency different than a predetermined frequency of a AC power grid (3), when a grid disconnect switch (11) is in an open position. The inverter is controlled to increase a test load acting on a DC voltage source (1) above internal consumption of the inverter at the predetermined frequency. The DC input voltages are measured, when the grid disconnect switch is in the open position. An independent claim is also included for a device for connecting a direct current (DC)- voltage source to an alternating current (AC)- power grid power grid having a predetermined frequency.