Patent ID: 9455575
Filing Date: 2016-09-27
CPC Classification: H02J,H02M,Y02E

Claim Text:
1. A voltage source converter for high voltage DC power transmission that is configured to be connectable, in use, between a DC network and an AC network to interconnect the DC network and the AC network, the voltage source converter comprising: a converter unit to convert power flowing between the DC network and the AC network, the converter unit including at least one phase element having a plurality of semiconductor switches, the at least one phase element having an AC terminal located at its mid-point and configured to be connected, in use, to the AC network and opposite ends of the at least one phase element being respectively connected to a first DC terminal and a second DC terminal; a fault unit connected to the first DC terminal to interconnect, in use, the converter unit and the DC network, and no fault unit connected to the second DC terminal, wherein the fault unit connected to the first DC terminal includes at least one fault module, wherein the at least one fault module includes a voltage source in the form of an energy storage device and at least one semiconductor switch, wherein in response to a short circuit in the DC network, the at least one semiconductor switch of the at least one fault module is configured to insert or bypass the voltage source of the at least one fault module, to provide the voltage required to oppose the driving voltage of the AC network and thereby reduce current flowing through the voltage source converter and the short circuit.