A method in a frequency converter provided with a voltage intermediate circuit in connection with interference in a network (5) to be supplied and a frequency converter (2), which comprises a network converter part (4) and an inverter part (3) and a DC intermediate circuit (7) between them. The method comprises steps of controlling the intermediate circuit voltage at the beginning of network interference by limiting the torque on the inverter side, detecting interference in the network voltage, setting a torque reference to a predetermined value in response to the network interference, detecting network voltage recovery, and controlling the torque reference to a normal value in response to the network voltage recovery.