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    Reduced Available Transfer Capability (ATC) into Alberta

    The Alberta Interconnected Electric System (AIES) experienced a significant disturbance event on June 7th, 2020 at 2:50 pm, due to the tripping of the interties with British Columbia and Montana. This resulted in the activation of the province’s Under-Frequency Load Shed (UFLS) program. The AIES was operating in a rare operating condition due to low system inertia exacerbated by relatively poor primary frequency response.

    The AESO is currently in the process of reviewing its operating procedures and practices to ensure the continued safe and reliable operation of the AIES during system events. Until this review is complete and operating procedures are amended accordingly, the AESO is limiting the Available Transfer Capability (ATC) on the combined British Columbia and Montana interties to no more than 550MW. It is expected that the revised operating procedures will be finalized and implemented by June 22nd. In addition to the reduced transfer capability, the ATC is further limited due to a planned transmission line outage in British Columbia, per existing operating procedures.

    Market participants will be notified if there are further updates or changes to expected timelines.