Abstract: A method is provided for operating a converter arrangement having a modular multilevel converter which includes at least one series circuit of double-pole switch modules, of which at least one first switch module is a full bridge switch module including controllable semiconductor switches and an energy storage device. The switches and the energy storage device are connected to one another in a full bridge circuit. After one of the semiconductor switches in the first switch module has been found to be defective, the first switch module continues to be operated as a half bridge switch module. A converter arrangement for carrying out the method is also provided.