Voltage source converter

A voltage source converter comprising:

• a converter arm extending between two terminals, wherein each terminal is configured to connect to at least one respective electrical network, the converter arm including at least one valve comprising at least one module, wherein the at least one module is configured to selectively provide a voltage source, wherein the two terminals comprise:
• a first terminal and a second terminal configured to connect to a first electrical network;
• and
• a phase limb extending between the first terminal and second terminal, wherein the phase limb comprises a first phase limb and a second phase limb separated by a third terminal, wherein each phase limb extends between the third terminal and the first terminal and second terminal respectively, and wherein the third terminal is configured to connect to a second electrical network, either or both of the first phase limb and second phase limb being in the form of a converter arm,
• wherein the controller is programmed to selectively operate the at least one valve to clamp a voltage at either or both of the third terminal and first terminal or the second terminal and operate the at least one valve as a current limiter to limit a selected current flowing in a respective converter arm at or below a fixed or variable current threshold;
• and
• a controller programmed to selectively operate the at least one valve to clamp a voltage at either or both of the two terminals and operate the at least one valve as a current limiter to limit a selected current flowing in the converter arm at or below a fixed or variable current threshold.