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    Available Transfer Capability Risk Mitigation and Operational Preparedness

    The Alberta Interconnected Electric System (AIES) experienced a significant disturbance event on June 7, 2020, at 2:50 p.m. due to the tripping of the interties with British Columbia (B.C.) and Montana (MT). As a result, Alberta customers were impacted due to the activation of the province’s Under-Frequency Load Shed (UFLS) program. Additionally, on Oct. 16, 2020, the loss of a generating unit while the AIES was operating in an islanded mode led to the frequency dropping to 59.6 Hz before recovering.

    The system experienced another event on Feb. 21, 2021 at 9:13 p.m. due to the tripping of the interties, which caused the activation of the province’s UFLS program. A similar event occurred on Feb. 22, 2021 at 6:22 p.m. due to the tripping of the interties; however, during this event, the UFLS program was not activated. 

    Increasing penetration levels of renewables and distributed energy resources (DER) on the system, combined with system frequency response and inertia concerns, provide a unique set of challenges in operating the grid of the future.

    An information session was held on March 9, 2021, to provide an update on the 2020 and 2021 events, and to provide an overview of various initiatives that are planned or currently underway to address AESO event analysis findings and operational preparedness as the grid evolves. The initiatives include:  

    • Monitoring system inertia and arming Load Shed Service for imports (LSSi) considering system inertia
    • Modeling appropriate generation governor response in system studies
    • Working with generator facility owners on specific issues observed during AESO investigations
    • Investigating the need for synthetic inertia
    • Exploring new products and services including technology-agnostic fast frequency response (FFR)
    • Developing performance metrics to measure system and generating unit response during system events

    A copy of the presentation and webinar audio recording are posted under “Related notices and materials.” Please refer to the audio file for questions and answers (all questions were addressed prior to the conclusion of the session).

    The AESO will continue to engage and collaborate with stakeholders as appropriate, as it progresses on these various initiatives. The AESO will be proactive in ensuring the continued reliability of the electricity grid, given the evolving grid and resource mix, and expects these initiatives to support this objective in the long term.

    Related notices and materials