HVDC life extension for Nelson River HVDC system

The Nelson River HVDC transmission system in Manitoba, Canada, is described with reference to equipment upgrades, equipment replacements and process improvements completed to meet safety, environmental and reliability performance goals. Today´s operational environment demands increased HVDC system performance, which in many cases exceeds original equipment capabilities. This, coupled with equipment which is approaching the end of its design life, has presented additional challenges beyond the standard maintenance requirements facing the Nelson River HVDC system over the last thirty years. Equipment upgrades, replacements and process improvements have enabled Manitoba Hydro to adapt to these demands and essentially extend the life of the HVDC facilities. Replacement of Pole 2 mercury-arc valves, upgrading of Bipole 2 cooling system, purchase of spare converter transformers, replacement of Bipole 2 thyristor module tubing, implementation of a reliability centered maintenance process, staff training and condition based monitoring are examples of recent initiatives geared towards improving HVDC transmission system performance.