September 2, 2009

WECC holds BAAL field trial workshop

On August 13, 2009, WECC held a meeting to discuss the potential field trial of the proposed BAAL standard in the Western Interconnection.

The standard proposes to replace the fixed CPS2 limit on the 10-minute average of ACE with a frequency-based limit. Balancing Authorities would be in violation if their ACE exceeded the new limit for more than 30 consecutive minutes. The proposed limit on ACE would generally be looser than CPS2 bounds and enable Balancing Authorities reduce their costs of operation.

The savings could appear in terms of

  • reduced unit maneuvering,
  • less deviation from optimum economic operation,
  • a decrease in the amount of needed expensive regulation reserve.
  • In times of large frequency deviation, however, the proposed standard may require more action from Balancing Authorities.

    Mike Mraz, Doug Hils, Don Badley, and Don Pape made presentations describing the standard and its expected impact on generation control. They covered the measures defined by the proposed standard and the procedures for implementing the field trial. Doug Hils also demonstrated the tools Duke has created for managing operation in the field trial. Their presentations are available on the WECC website.

    In the development of the BAAL, PCE was hired to perform "Directed Research to Validate Balance Resources and Demand Standard’s Procedures and Define Frequency-Related Limits". PCE’s findings, including basis for and discussion of the WECC frequency limits and related measures, are published in a report available on the NERC RBC SDT page. Dr. Nasser Jaleeli and Alex Podolsky, two of the principal investigators of this research, attended the workshop and participated in the discussions.

    The meeting led to a number of interesting discussions. Don Watkins, Chairman of the WECC Operating Committee, gave his opinion that, in order for the field trial provide a meaningful evaluation of the proposed standard, BAs should provide for generation control processes that will take advantage of BAAL. The meeting voiced consensus with this idea. The discussion concluded that EMS of field trial participants should incorporate a switch enabling BAs to quickly switch between the BAAL-optimized and their original AGC.

    Another significant question was raised in the meeting: how could BAs properly control to ATEC when ACE reported for CPS1 and BAAL should exclude ATEC bias? Dr. Jaleeli pointed out it is possible to design an algorithm that controls to multiple objectives – PCE's generation control algorithm in its PGC software does just that, optimizing control between NERC standards, ATEC, net interchange constraints, and other considerations.

    WECC plans to have the field trial specification document ready for an Operating Committee vote in October 2009 and a WECC Board vote in December 2009. Should the field trial be approved, WECC expects to launch it in March 2010.

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