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Primary Frequency Response

PFR. Immediate proportional response to system Frequency Deviations.

Definition by NERC

Source: 1

The immediate proportional increase or decrease in real power output provided by generating units/generating facilities and the natural real power dampening response provided by Load in response to system Frequency Deviations. This response is in the direction that stabilizes frequency.

Relevant news:

  • 2022 Feb., 2 p1, Based on PJM’s frequency response analysis and oscillation detection using highly granularity PMU data, in addition to NERC Resource Subcommittee analysis, there are no near term concerns with inertia in the EI.
  • 2021 Nov., 3 p4, PJM proposed "Reliability Products and Services" that involves Inertial in the Frequency Response.
  • 2021 March, 4 p11, Inertial and Primary Frequency Response: Generators that provide these types of frequency response are not explicitly compensated for this service under today’s rules.

Last modified: 2025-06-22

Related: fast-frequency-response · primary-control · secondary-control · tertiary-control · frequency-regulation · automatic-generation-control · frequency-stability

← Primary Control · Quasi-Static Simulation →

  1. NERC (2025). Glossary of Terms Used in NERC Reliability Standards. https://www.nerc.com/pa/Stand/Glossary%20of%20Terms/Glossary_of_Terms.pdf ↩

  2. PJM (2022). Item 16: Reliability Products & Service Assessment. https://www.pjm.com/-/media/DotCom/committees-groups/committees/oc/2022/20220210/20220210-item-16-reliability-products-and-service-assessment.pdf ↩

  3. PJM (2021). Capacity Market Reform Phase 2 Reliability Services. https://www.pjm.com/-/media/DotCom/committees-groups/committees/oc/2021/20211104/20211104-item-13-reliability-products-and-services-assessment.ashx ↩

  4. PJM (2021). Reliability in PJM: Today and Tomorrow. https://www.pjm.com/-/media/DotCom/library/reports-notices/special-reports/2021/20210311-reliability-in-pjm-today-and-tomorrow.ashx ↩