A converter valve hall comprising an enclosed, open space within which electric equipment is arranged, the electric equipment comprising power electronics equipment electrically connected to a power transmission system, wherein the converter valve hall further comprises a cooling arrangement for use in conjunction with a first cooling circuit (3, 4) and at least one exterior heat exchanger unit for cooling the enclosed, open space, wherein the electric equipment is coupled to the first cooling circuit (3, 4) which extends to the outside of the enclosed, open space, the first cooling circuit being configured to convey cooling medium between the electric equipment and the at least one exterior heat exchanger unit arranged outside the enclosed, open space for cooling the electric equipment, the cooling arrangement comprising: at least one interior heat exchanger unit arrangeable within the enclosed, open space; and a second cooling circuit (8, 9) which is configured so that it can be coupled to the at least one interior heat exchanger unit and which is configured to convey cooling medium to and from the at least one interior heat exchanger unit; wherein the second cooling circuit is configured so that it can be coupled to the first cooling circuit such that the at least one interior heat exchanger unit by means of the first cooling circuit and the second cooling circuit becomes coupled in parallel with the electric equipment; and wherein the at least one interior heat exchanger unit is controllable with respect to operation thereof, and wherein the cooling arrangement further comprises: a temperature sensor configured to sense temperature within the enclosed, open space; and a control unit configured to control operation of the at least one interior heat exchanger unit based on temperature within the enclosed, open space sensed by the temperature sensor. at least one interior heat exchanger unit arrangeable within the enclosed, open space; and a second cooling circuit (8, 9) which is configured so that it can be coupled to the at least one interior heat exchanger unit and which is configured to convey cooling medium to and from the at least one interior heat exchanger unit; wherein the second cooling circuit is configured so that it can be coupled to the first cooling circuit such that the at least one interior heat exchanger unit by means of the first cooling circuit and the second cooling circuit becomes coupled in parallel with the electric equipment; and wherein the at least one interior heat exchanger unit is controllable with respect to operation thereof, and wherein the cooling arrangement further comprises: a temperature sensor configured to sense temperature within the enclosed, open space; and a control unit configured to control operation of the at least one interior heat exchanger unit based on temperature within the enclosed, open space sensed by the temperature sensor. a temperature sensor configured to sense temperature within the enclosed, open space; and a control unit configured to control operation of the at least one interior heat exchanger unit based on temperature within the enclosed, open space sensed by the temperature sensor.