The Federal Energy Regulatory Commission has proposed a new reliability standard to address the vulnerability of the nation’s electric grid to geomagnetic disturbances.
In May 2013, FERC directed the North American Electric Reliability Corp. to develop and submit new geomagnetic disturbance standards in a two-stage process. FERC addressed the first stage of the process last year by approving a standard on implementation of operating plans, procedures and processes to mitigate the effects of geomagnetic disturbances. Operators are required to develop and implement plans to protect against instability, uncontrolled separation or cascading failures.
GMDs caused by solar events distort, with varying intensities, the earth’s magnetic field. They can have potentially severe, widespread effects on reliable grid operation, including blackouts and damage to critical or vulnerable equipment.
FERC issued a notice of proposed rulemaking (RM15-11) on May 14, addressing the second stage of the GMD standards. It would set requirements for transmission planners and owners to assess the vulnerability of their systems to a “benchmark GMD event,” which NERC described as a one-in-100-year event. If an entity does not meet certain performance requirements based on the assessments, it must develop a plan to achieve the requirements.
The proposed standard would require transmission planners and owners to have system models needed to complete vulnerability assessments, to have criteria for acceptable steady state voltage performance during a benchmark event, and to complete a vulnerability assessment every 60 months. If the assessment indicates that a system does not meet the performance requirements, the entity would have to develop a corrective action plan.
The proposed rules also would require NERC to make modifications. FERC said because there is limited historic data on GMDs and because scientific understanding of GMDs is still evolving, FERC is concerned how a benchmark GMD event is defined in the standard. The proposed rules would require that the study and benchmarking of GMD events be based on a more complete set of data and a reasonable scientific and engineering approach.
The Notice of Proposed Rulemaking may be obtained from FERC’s Internet site under http://www.ferc.gov/whats-new/comm-meet/2015/051415/E-1.pdf. Comments are due 60 days after its publication in the Federal Register.