An electrical assembly for use in a power transmission network, the electrical assembly comprising: a converter including: a first terminal; and a second terminal for connection to an electrical network, wherein the first terminal is a DC terminal; and a plurality of modules, each including at least one pair of module switches that are connected in parallel with a capacitor; a DC power transmission medium operatively connected to the DC terminal; a circuit interruption device operatively connected in series between the DC power transmission medium and the converter, the circuit interruption device including at least one switching element and an energy absorption element, the or each switching element of the circuit interruption device being arranged and switchable to divert a flow of current in the DC power transmission medium through the energy absorption element in order to reduce the flow of current in the DC power transmission medium, the energy absorption element including a surge arrester; and a converter control unit programmed to control the switching of the module switches of the modules of the converter in order to operate each module to selectively provide a voltage source during normal operation and characterized in that the converter control unit is further programmed to control the switching of the module switches of the modules of the converter in order to operate the converter to control a DC voltage at the DC terminal in a leakage current reduction mode by controlling the switching of the module switches of the modules of the converter so as to control a voltage across the energy absorption element to reduce a leakage current flowing in the DC power transmission medium subsequent to the reduction of the flow of current in the DC power transmission medium through the switching of the or each switching element of the circuit interruption device to divert the flow of current in the DC power transmission medium through the energy absorption element. a converter including: a first terminal; and a second terminal for connection to an electrical network, wherein the first terminal is a DC terminal; and a plurality of modules, each including at least one pair of module switches that are connected in parallel with a capacitor; a DC power transmission medium operatively connected to the DC terminal; a circuit interruption device operatively connected in series between the DC power transmission medium and the converter, the circuit interruption device including at least one switching element and an energy absorption element, the or each switching element of the circuit interruption device being arranged and switchable to divert a flow of current in the DC power transmission medium through the energy absorption element in order to reduce the flow of current in the DC power transmission medium, the energy absorption element including a surge arrester; and a converter control unit programmed to control the switching of the module switches of the modules of the converter in order to operate each module to selectively provide a voltage source during normal operation and characterized in that the converter control unit is further programmed to control the switching of the module switches of the modules of the converter in order to operate the converter to control a DC voltage at the DC terminal in a leakage current reduction mode by controlling the switching of the module switches of the modules of the converter so as to control a voltage across the energy absorption element to reduce a leakage current flowing in the DC power transmission medium subsequent to the reduction of the flow of current in the DC power transmission medium through the switching of the or each switching element of the circuit interruption device to divert the flow of current in the DC power transmission medium through the energy absorption element.