More analysis of actual data is required before NERC proposes reliability standards for mitigating geomagnetic disturbances (GMD) to the bulk power system, the ISO/RTO Council (IRC) said in a filing to FERC on May 21.
“National standards would likely be inefficient as the effects of GMD are local and diverse,” the IRC said in the filing. “Further, hard-coding reliability standards at this time could also stifle the development of the necessary tools and information sharing that will be critical to cost effective action.”
The council submitted the comments after FERC on April 30 held a staff technical conference on the reliability of the bulk power system as affected by GMD. Comments were due May 21.
NERC should work with stakeholders on a repository of geomagnetically induced currents (GIC) indicators, the IRC said.
“Such a list would permit researchers to correlate instances of GIC to actual observed impacts,” providing a valuable fact-finding tool to assess the frequency and impact of GIC events that would be the basis for “appropriate fact-based responses,” the IRC said.
The IRC said that NERC’s interim report provides a sound framework for continuous improvement and a risk assessment methodology that “establishes a sound basis for the industry to evaluate risks while gathering facts that can provide a basis for specific actions.”
The interim report also suggests that developing a list of transformers that are vulnerable to the effects of GIC would be important for developing a technical standard for manufacturers that rates a transformer’s GIC resiliency and for decision-making, the IRC said.
“Such a standard would provide useful information to potential purchasers and the industry,” the IRC said.
The council said it supported certain implementation strategies PJM Interconnection suggested during a staff technical conference FERC held on the effects of GMD to the bulk power system in April: to assess extra high voltage (EHV) transformers, specify geomagnetically induced current (GIC) withstand in new transformers, develop operating procedures to respond to GMD events, and incorporate GMD impacts into power system analysis.
“GMD impacts can be modeled and assessed as part of overall power system analysis performed by system planners and operators,” the IRC said. “While these tools are not yet mature, progress is steadily being made and planners and operators need to begin to acquire this knowledge and start the process of incorporating the many complex aspects of GMD into their planning and operating procedures and processes.”
In assessing EHV transformers, each asset owner needs to determine the overall health of its EHV transformer fleet and develop strategies for GIC mitigation for identified vulnerable transformers, even before more detailed analysis capability is available, IRC said.
The IRC comprises the Alberta Electric System Operator (AESO), the California ISO, ERCOT, the Independent Electricity System Operator of Ontario (IESO), ISO New England, the Midwest ISO, New York ISO, PJM Interconnection, Southwest Power Pool, and New Brunswick System Operator (NBSO).
AESO and NBSO abstained from these comments as they are not subject to FERC jurisdiction.