When It's Time to Upgrade: HVdc and FACTS Renovation in the Western Power System

The western United States and Canada, bounded roughly by the Continental Divide and the Pacific Ocean and Mexico, form a large interconnected power system overseen by the Western Electric Coordinating Council (WECC). This interconnected system of approximately 210,000 MW has five high-voltage dc (HVdc) transmission systems dating from 1970 to 2014. Two new HVdc transmission schemes have been completed recently in Alberta, and several HVdc lines are being planned for the southwest to move power to southern California. There are also eight back-to-back converters that tie the western system to the eastern interconnection and to Texas. Other power electronic installations include a number of large transmission scale static var converters (SVCs) and two thyristor controlled series capacitors (TCSCs). These installations date from 1970, when the Vancouver Island HVdc transmission was installed.