Patent ID: 8553437

Claim:
A method for controlling power flow within a DC power transmission network comprising two or more interconnected converter stations, said method comprising the steps of: establishing a common feedback signal (U d,common , Ũ d,common ) for said converter stations, said common feedback signal (U d,common , Ũ d,common ) being based on a voltage level at one, two or more converter stations in said DC transmission power network; providing, in said converter stations, a control signal (S 1 , S 2 , S 3 , S 4 ) based on said common feedback signal (U d,common , Ũ d,common ) and a drooped error signal (P e,droop , U e,droop ) and controlling said power flow within said DC power transmission network towards set operating points (U d ref , P PCC ref ) by using said control signal (S 1 , S 2 , S 3 , S 4 ), wherein said converter stations comprises communication means enabling communication them between, and wherein said step of establishing a common feedback signal comprises communicating, by means of communication means, a common feedback signal (U d,common ) to said converter stations.