External WECC model reduction in on-line network applications for Alberta power grid

Alberta power grid is connected to the Western Interconnection of North America via three tie-lines to BC Hydro, where BC Hydro and the rest of WECC system are modeled as a single radial connection in network applications of EMS. With the addition of another tie-line in 2013, the “Montana-Alberta Tie-Line”, it is necessary to revisit how the WECC system should be modeled in network applications. This paper describes the concept, methodologies, and strategies in reducing the external WECC model for Alberta power grid after the new tie-line is in service. The validation results on the reduced model are also provided.