A converter station an element adapted to determine a value of an actual temperature of any critical component of the station and an element adapted to determine a value of an actual temperature of any media used to cool the critical component. An arrangement is adapted to utilize these temperature values and information about actual cooling capacity of any cooling equipment present to cool the critical component and information about the thermal behavior of the critical component and the possible cooling media upon a possible change of the power actually transmitted through the station in a mathematical model for calculating the present overload capabilities of the converter station for use in the control of converters of the station upon a possible request of utilizing an overload capability of the station.