Determining the DC component in reactive power compensators comprising a mulitlevel converter

The method involves connecting an alternating-current (AC) path to an AC mains, and connecting an electrical memory circuit in series with the AC path. A capacitor of the memory circuit is associated with a switching device that is driven such that a charge state of the capacitor oscillates with an integer multiple of the mains frequency. A voltage drop across the capacitor is measured (S5) and filtered (S6), and a direct current (DC) component of a current flowing in the AC path is determined (S7) using the filtered voltage, where actions are taken (S8) based on the determined DC component. An independent claim is also included for a computer program for determining a DC component in a total current flowing in an AC path.