A bipole power transmission scheme comprising a first converter station positioned in-use remote from a second converter station, and first and second transmission conduits (18, 20) and a return conduit to in-use interconnect the first converter station with the second converter station and thereby permit the transfer of power (P DC1, P DC2) between the first and second converter stations (12, 14), the first converter station including: a first power converter having a first DC terminal connected with the first transmission conduit, a second DC terminal connected with the return conduit, and at least one first AC terminal electrically connected with a point of common coupling for connection to an AC network element operating at a reference phase angle, the first power converter further having a first converter controller programmed to control the transfer of power between the first transmission conduit and the point of common coupling by having the first power converter provide a first AC voltage (V AC1) at the or each first AC terminal which is presented to the point of common coupling; a second power converter having a third DC terminal connected with the return conduit, a fourth DC terminal connected with the second transmission conduit, and at least one second AC terminal electrically connected with the point of common coupling, the second power converter further having a second converter controller programmed to control the transfer of power between the second transmission conduit and the point of common coupling by having the second power converter provide a second AC voltage (V AC2) at the or each second AC terminal which is presented to the point of common coupling; and a converter station controller arranged in operative communication with each of the first and second converter controllers (46, 56) whereby the first and second power converters (30, 48) are controlled as grid forming converters such that the first and second AC voltages (V AC1, V AC2) presented to the point of common coupling manage the AC frequency (f) and AC voltage at the point of common coupling, characterized in that the converter station controller being programmed to operate the first converter station in a current distribution mode in which the distribution of DC current (I DC1, I DC2) between the first and second transmission conduits (18, 20) is controlled, the converter station controller when operating the first converter station in the current distribution mode being programmed to instruct the first converter controller to adjust the operating phase angle of the first AC voltage (V AC1) provided at the or each first AC terminal in a first direction relative to the reference phase angle at the point of common coupling and instruct the second converter controller to adjust the operating phase angle of the second AC voltage (V AC2) provided at the or each second AC terminal in a second direction opposite the first direction relative to the reference phase angle at the point of common coupling. a first power converter having a first DC terminal connected with the first transmission conduit, a second DC terminal connected with the return conduit, and at least one first AC terminal electrically connected with a point of common coupling for connection to an AC network element operating at a reference phase angle, the first power converter further having a first converter controller programmed to control the transfer of power between the first transmission conduit and the point of common coupling by having the first power converter provide a first AC voltage (V AC1) at the or each first AC terminal which is presented to the point of common coupling; a second power converter having a third DC terminal connected with the return conduit, a fourth DC terminal connected with the second transmission conduit, and at least one second AC terminal electrically connected with the point of common coupling, the second power converter further having a second converter controller programmed to control the transfer of power between the second transmission conduit and the point of common coupling by having the second power converter provide a second AC voltage (V AC2) at the or each second AC terminal which is presented to the point of common coupling; and a converter station controller arranged in operative communication with each of the first and second converter controllers (46, 56) whereby the first and second power converters (30, 48) are controlled as grid forming converters such that the first and second AC voltages (V AC1, V AC2) presented to the point of common coupling manage the AC frequency (f) and AC voltage at the point of common coupling, characterized in that the converter station controller being programmed to operate the first converter station in a current distribution mode in which the distribution of DC current (I DC1, I DC2) between the first and second transmission conduits (18, 20) is controlled, the converter station controller when operating the first converter station in the current distribution mode being programmed to instruct the first converter controller to adjust the operating phase angle of the first AC voltage (V AC1) provided at the or each first AC terminal in a first direction relative to the reference phase angle at the point of common coupling and instruct the second converter controller to adjust the operating phase angle of the second AC voltage (V AC2) provided at the or each second AC terminal in a second direction opposite the first direction relative to the reference phase angle at the point of common coupling.