A reliability standard requiring transmission planners and owners to assess the vulnerability of their systems to a “one-in-100-year” event caused by distortions of Earth’s magnetic fields has been proposed for approval by the U.S. Federal Energy Regulatory Commission (FERC).

Geomagnetic disturbances are caused by solar events. Source: sedonanomalies.com Geomagnetic disturbances (GMDs) are caused by solar events. These are considered to be “high impact, low frequency” events, but can have potentially severe, widespread effects on reliable grid operation, including blackouts and damage to critical or vulnerable equipment. If an entity does not meet certain performance requirements based on the assessments, it must develop a plan to achieve the requirements and act on the plan in a timely manner.

In May 2013, FERC directed the North American Electric Reliability Corporation (NERC), to develop and submit GMD standards through a two-stage process. FERC addressed the first stage in June 2014 by approving a standard on implementation of operating plans, procedures, and processes to mitigate effects of GMD.

The FERC’s Notice of Proposed Rulemaking (NOPR) addresses the second stage and would adopt NERC’s proposed standard that sets requirements for assessing the vulnerability of systems to a “benchmark GMD event.”

The standard would require entities 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 once every 60 months.