CERTS Research Supporting Definition and Validation of a Frequency Response Standard

The electric power industry is developing frequency response requirements to maintain and/or enhance reliable power system operation. This North American Electric Reliability Corporation (NERC) effort must determine the minimum interconnection frequency response needed for reliability and how to ensure that appropriate entities provide that response. Critical components to support this NERC effort are identifying frequency events of interest, calculating frequency response for those events, and providing a viable and reliable methodology to measure interconnection and Balancing Authority (BA) Area frequency response. This report provides information related to this NERC effort.

This research is part of Phase 3 of U.S. Department of Energy (DOE)- and Consortium for Electric Reliability Solutions (CERTS)-supported research on interconnection frequency response performance and reliability standards, which began in 2007. Phase 3 has three objectives. The first is to investigate automatic methods to identify interconnection frequency events by extending and validating an approach recommended by Florida Region representatives and using phasor one-second frequency data. The second objective is to research a methodology for automatically estimating and validating interconnection frequency response for the events identified by the investigations described under the first objective. This would be accomplished by using NERC Frequency Response Standard Drafting Team (FRSDT) definitions of frequency events for locations of points A, B and C; and BA with the highest area control error (ACE) during frequency events or ACE for the contingent BA. The final Phase-3 objective is to investigate interconnection frequency events and frequency response statistical performance and patterns during different temporal periods as well as during on-off peak, ramps, and time error correction (TEC) periods, assessing their impact on the definition of adequate sets of frequency events.

All three objectives researched in this report apply directly to NERC efforts to identify frequency events automatically and calculate frequency response automatically, and inform methodologies to measure frequency response automatically. The research team is working closely with the industry to ensure that our research addresses appropriate issues within the stated research objectives.

Key components of the proposed standard for frequency response are: first, identify an appropriate yearly list of frequency events for each interconnection that will be used by all BAs as a basis for consistently calculating their yearly frequency response performance; and, second, estimate interconnection frequency response using NERC archived data compared with frequency response performance data that BAs will submit to NERC. These data is also useful for tuning an interconnection’s yearly frequency response requirement.