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    MSSC Reduction

    The Interconnected Electric System (IES) is currently islanded from the rest of Western Interconnection due to a planned outage to perform maintenance work on the Alberta to British Columbia intertie, which also requires the Montana intertie to be opened. Due to unforeseen circumstances, and in order to ensure the safe and reliable operation of the IES during frequency excursion events following potential loss of internal generation, the AESO has currently limited the Most Severe Single Contingency (MSSC) to 400 MW. Therefore, the AESO will limit generation output from each single asset in the IES during the planned outage period according to the reduced MSSC, and apply Section 302.1 of the ISO rules, Real Time Transmission Constraint Management, as necessary and as applicable. The islanded operation is expected to continue until October 30th, 2020.