A power transmission arrangement configured to electrically couple a first power system with a second power system, the first power system and the second power system being electrically connected with a first converter station and a second converter station, respectively, each of the first converter station and the second converter station being configured to convert AC power to DC power or vice versa, the power transmission arrangement comprising: at least one power transmission line, wherein the first power system is selectively electrically connectable to one end of the power transmission line via the first converter station and the second power system is selectively electrically connectable to the other end of the power transmission line via the second converter station, wherein the first converter station is arranged at the one end of the power transmission line and the second converter station is arranged at the other end of power transmission line; at least one electrical energy storage element that can be selectively charged or discharged and is selectively electrically connectable to at least a portion of one of the first converter station and the second converter station such that the at least one electrical energy storage element when discharged can convey power to the at least a portion of the one of the first converter station and the second converter station; and at least one auxiliary converter (180; 190) that can be selectively electrically connected to the power transmission line and which is electrically connected to the at least one electrical energy storage element such that the at least one electrical energy storage element can be charged by power output from the at least one auxiliary converter; characterized in that the power transmission arrangement is configured to convert power from the one of the first power system and the second power system that is at the end of the power transmission line at which the other one of the first converter station and the second converter station is arranged, to DC or AC power at a lower voltage than the nominal operating voltage of the other one of the first converter station and the second converter station, and selectively cause the DC or AC power to be conveyed to the at least one auxiliary converter via the power transmission line when the one of the first converter station and the second converter station is de-energized so as to charge the at least one electrical energy storage element, whereby power can be conveyed to the at least a portion of the one of the first converter station and the second converter station when it is de-energized by discharging of the at least one electrical energy storage element. at least one power transmission line, wherein the first power system is selectively electrically connectable to one end of the power transmission line via the first converter station and the second power system is selectively electrically connectable to the other end of the power transmission line via the second converter station, wherein the first converter station is arranged at the one end of the power transmission line and the second converter station is arranged at the other end of power transmission line; at least one electrical energy storage element that can be selectively charged or discharged and is selectively electrically connectable to at least a portion of one of the first converter station and the second converter station such that the at least one electrical energy storage element when discharged can convey power to the at least a portion of the one of the first converter station and the second converter station; and at least one auxiliary converter (180; 190) that can be selectively electrically connected to the power transmission line and which is electrically connected to the at least one electrical energy storage element such that the at least one electrical energy storage element can be charged by power output from the at least one auxiliary converter;