Improvements in or relating to bipole power transmission networks

A bipole power transmission network, comprising:

• a first converter station positioned in-use remote from a second converter station and having first and second power converters;
• first and second transmission conduits and a return conduit to in-use interconnect the first converter station with the second converter station and thereby permit the transfer of power between the first and second converter stations, the first transmission conduit extending from the first power converter whereby at least the first power converter and the first transmission conduit together define a first transmission pole, the second transmission conduit extending from the second power converter whereby at least the second power converter and the second transmission conduit together define a second transmission pole, and each conduit having a current sensor associated therewith to measure the current flowing therein;
• and
• a controller arranged in operative communication with each current sensor to receive current flow information from each current sensor, the controller being programmed to identify a faulty first or second transmission pole by:
• interrogating the current flow information received from each current sensor to establish whether the current flowing in a respective conduit has changed in a first direction or a second direction opposite the first direction;
• and
• identifying a faulty first or second transmission pole according to a predefined relationship between the changes in current flow direction in the respective conduits.

A method of operating a bipole power transmission network, comprising a first converter station positioned in-use remote from a second converter station and having first and second power converters, first and second transmission conduits, and a return conduit to in-use interconnect the first converter station with the second converter station and thereby permit the transfer of power between the first and second converter stations, the first transmission conduit extending from the first power converter whereby at least the first power converter and the first transmission conduit together define a first transmission pole, the second transmission conduit extending from the second power converter whereby at least the second power converter and the second transmission conduit together define a second transmission pole, and each conduit having a current sensor associated therewith to measure the current flowing therein, and the bipole power transmission scheme further comprising a controller arranged in operative communication with each current sensor to receive current flow information from each current sensor,

• the method of the invention comprising the steps of having the controller:
• interrogate the current flow information received from each current sensor to establish whether the current flowing in a respective conduit has changed in a first direction or a second direction opposite the first direction;
• and
• identify a faulty first or second transmission pole according to a predefined relationship between the changes in current flow direction in the respective conduits.