In the field of high voltage direct current power transmission networks, a voltage source converter comprises first and second DC terminals for connection to a DC electrical network, and a plurality of single-phase limbs. Each single-phase limb includes a phase element, and each phase element includes at least one switching element configured to interconnect a DC voltage and an AC voltage. An AC side of each phase element is connectable to a respective phase of a multi-phase AC electrical network, and each single-phase limb is connected between the first and second DC terminals. The voltage source converter further comprises a controller configured to determine independently of one another an amount of active power (Pref) that the voltage source converter should exchange with the AC electrical network and an amount of reactive power (Qref) that the voltage source converter should exchange with the AC electrical network.