Source: Proceeding of GRIDTECH 2011, 19–21 April 2011, New Delhi
Alstom Grid has extended its range of equipment to allow the offering of a full turnkey Ultra High Voltage Direct Current (UHVDC) projects at voltages up to ±800 kV. This paper describes the design and testing of the key technologies required for a UHVDC converter station. A converter transformer test object has been successfully tested, including the through wall bushing which connects into the valve hall. The thyristor valves required a new design of corona shield to ensure safe operation at 800 kV. These have now been fully tested to the highest DC and transient voltage waveforms. A single chamber fast acting by-pass switch has been developed and fully tested, for use in schemes where two series connected 12-pulse bridges are required. To connect the valve hall to the outdoor DC equipment a new dry-type wall bushing has been built and tested. A new range of DC current transducers to provide high accuracy measurement for control and protection purposes, have been developed and fully tested. Disconnects to provide isolation of the DC circuit have been designed and are now on long term test at an outdoor test facility.
