Current converter unit for high-voltage direct current transmission - having a first current converter and a second current converter, - wherein a first DC voltage terminal of the first current converter can be connected to a first conductor terminal point for a first high-voltage direct current transmission conductor, - wherein a second DC voltage terminal of the first current converter is connected to a first DC voltage terminal of the second current converter such that a connection point is formed, - wherein a second DC voltage terminal of the second current converter can be connected to a second conductor terminal point for a second high-voltage direct current transmission conductor, - having a direct current switch, wherein the connection point is connected to a grounding electrode by means of the direct current switch, and - having a first transformer and a first AC power circuit-breaker, wherein an AC voltage terminal of the first current converter is connected to a secondary winding of the first transformer, and a primary winding of the first transformer can be connected via the first AC power circuit-breaker to an energy supply system, characterized in that - the current converter unit has a current-damping electrical component, wherein the connection point is connected to the grounding electrode by means of the current-damping electrical component, - the direct current switch is connected in parallel with the component, wherein the current converter unit is set up in such a way that - in response to a fault at the AC voltage terminal of the first current converter, specifically in response to a single-pole or two-pole fault (internally to the current converter) at the AC voltage terminal of the first current converter, the direct current switch opens, - thereafter, a current flowing through the direct current switch commutates from the direct current switch to the current-damping electrical component, - the current is damped by means of the component and a voltage is built up at the component, as a result of which an alternating current flowing through the primary winding of the first transformer incorporates zero-crossings, such that said alternating current can be interrupted by means of the first AC power circuit-breaker, and - thereafter, the first AC power circuit-breaker opens. - having a first current converter and a second current converter, - wherein a first DC voltage terminal of the first current converter can be connected to a first conductor terminal point for a first high-voltage direct current transmission conductor, - wherein a second DC voltage terminal of the first current converter is connected to a first DC voltage terminal of the second current converter such that a connection point is formed, - wherein a second DC voltage terminal of the second current converter can be connected to a second conductor terminal point for a second high-voltage direct current transmission conductor, - having a direct current switch, wherein the connection point is connected to a grounding electrode by means of the direct current switch, and - having a first transformer and a first AC power circuit-breaker, wherein an AC voltage terminal of the first current converter is connected to a secondary winding of the first transformer, and a primary winding of the first transformer can be connected via the first AC power circuit-breaker to an energy supply system, characterized in that - the current converter unit has a current-damping electrical component, wherein the connection point is connected to the grounding electrode by means of the current-damping electrical component, - the direct current switch is connected in parallel with the component, wherein the current converter unit is set up in such a way that - in response to a fault at the AC voltage terminal of the first current converter, specifically in response to a single-pole or two-pole fault (internally to the current converter) at the AC voltage terminal of the first current converter, the direct current switch opens, - thereafter, a current flowing through the direct current switch commutates from the direct current switch to the current-damping electrical component, - the current is damped by means of the component and a voltage is built up at the component, as a result of which an alternating current flowing through the primary winding of the first transformer incorporates zero-crossings, such that said alternating current can be interrupted by means of the first AC power circuit-breaker, and - thereafter, the first AC power circuit-breaker opens.