FERC Approval Still Pending for Second Phase of NERC’s
Geomagnetic Disturbance Planning and Mitigation Program
This Fall, FERC continues to deliberate on the approval of TPL-007-1, the standard to implement the second
phase of NERC’s Geomagnetic Disturbance (GMD) program.
While the initial Notice of Proposed Rulemaking (NOPR) comment period closed months ago, Congress has
called on FERC to revisit the standard and ensure that it provides adequate protection for reliability. Recently
FERC extended the comment period until October 22, 2015 to allow for additional commenters to submit their
views regarding the GMD benchmark.
Despite the current regulatory uncertainty, planning ahead to meet compliance obligations will support success.
Background
GMDs induce electric currents in the Earth’s surface. When these currents enter the power system, they disrupt
protection systems and negatively impact large transformers. These events can cause power outages and lead to
early failure of equipment that has a long lead time to replace and repair.
Under TPL-007-1 owners and operators of the Bulk Power System are required to conduct initial and on-going
vulnerability assessments of the potential impact GMD events may have on power system equipment and the
power system as a whole. Utilities that do not meet the requirements under the standard, based on the results
of their vulnerability assessments, must develop a plan to achieve the requirements.
Many utilities and other organizations filed comments as part of the NOPR process both in support of the
standard as written and proposing modifications to the standard. Some comments advocate for making the
standard more stringent.
In its NOPR FERC expressed some concerns and sought comments on the parameters used for the benchmark
GMD event described in Attachment 1 of TPL-007-1. FERC noted that while there is limited historical
geomagnetic data and scientific understanding of geomagnetic disturbance events, their concern related to the
proposed Reliability Standard’s heavy reliance on spatial averaging. FERC proposed to direct NERC to make
several modifications to better ensure that, going forward, the study and benchmarking of geomagnetic
disturbance events are based on a more complete set of data and a reasonable scientific and engineering
approach. FERC also proposed specific revisions to Requirement R7 of the proposed Reliability Standard to
ensure that, when a utility identifies the need for a corrective action plan, the utility acts in a timely manner.
NERC submitted comments supporting the standard as written and did not support the FERC proposals for
change.
For more information, please contact: Jim Whitaker, Supervisor of Power System Studies at jwhitaker@trcsolutions.com or
303.395.4018.
New Mandatory Obligations
In the second stage of NERC’s GMD regulatory program, utilities in the Planning Coordinator, Transmission
Planner and Transmission Owner functions must identify benchmark GMD events and specify the magnitude of
event a responsible entity must assess against. A vulnerability assessment1 is required for transformers with a
high-side, wye ground winding with terminal voltage greater the 200kV2. If the assessments identify potential
impacts, owners and operators are required to develop and implement corrective action plans to protect against
instability, uncontrolled separation, or cascading failures of the BPS.
Each utility that concludes through the GMD Vulnerability Assessment that their System does not meet the
performance requirements must develop a formal Corrective Action Plan. The development of proactive
strategies is based on the age, condition, technical specifications, system configuration, and location of specific
equipment.
These strategies could, for example, include:




Consideration of automatically blocking geomagnetic currents from entering the BPS;
Instituting more stringent specifications for new equipment;
Improved spare equipment inventory management; and
Isolating certain equipment that is not cost effective to retrofit.
Regulated entities will need to review existing procedures or develop and implement new procedures in order
to maintain compliance. Critical areas of attention include:




Systems configurations
Modeling and analysis
Monitoring and measurement
Mitigation planning
1
The study or studies shall include the following conditions:
 System On-Peak Load for at least one year within the Near-Term Transmission Planning Horizon; and
 System Off-Peak Load for at least one year within the Near-Term Transmission Planning Horizon.
 The study or studies shall be conducted based on the benchmark GMD event described in Attachment 1 of TPL007-1 to determine whether the System meets the performance requirements in Table 1 of TPL-007-1.
 The GMD Vulnerability Assessment shall be provided within 90 calendar days of completion to the responsible
entity’s Reliability Coordinator, adjacent Planning Coordinators, adjacent Transmission Planners, and to any
functional entity that submits a written request and has a reliability-related need.
2
The GIC application guide is available at:
http://www.nerc.com/comm/PC/Geomagnetic%20Disturbance%20Task%20Force%20GMDTF%202013/GIC%20Application
%20Guide%202013_approved.pdf
For more information, please contact: Jim Whitaker, Supervisor of Power System Studies at jwhitaker@trcsolutions.com or
303.395.4018.
NERC continues to support the industry with technical guidance in order to comply with the proposed standard.
NERC is also raising awareness about the impact of GMD on the power system through information exchange
and focused training between industry, researchers and policymakers.
TRC Can Help
While we await the outcome of FERC’s deliberations on the standard, it is not too soon to begin to develop your
plans to address the new obligations. There is a great deal of modeling called for in the standard which may be
unfamiliar to your current staff.
TRC is well positioned to assist you with studies in this new area of utility planning. We have the engineering
resources and experience to support your company’s vulnerability assessment and mitigation planning under
TPL-007-1.
Resources
2012 NERC Interim report on the Effects of Geomagnetic Disturbances on the Bulk power System
FERC Order 799 Concerning GMDs
NERC GMD Task Force page
GMD Planning Guide
NERC TPL-007-1 filing to FERC
TPL-007-1
FERC NOPR on TPL-007-1
TRC NERC Compliance Support Services
TRC Power Delivery Engineering Services
About Us
TRC’s Power Delivery Engineers provide full service transmission planning, consulting and construction
management for utilities, municipalities and industry. Comprised of over 1,000 personnel, many of whom are
experienced utility engineers, our project teams know how to plan, design, and install facilities that meet a
client’s financial, technical, and scheduling goals.
This regulatory update is a service to our utility clients, helping keep you informed of issues that impact your
reliability risk and business goals.
October 14, 2015
For more information, please contact: Jim Whitaker, Supervisor of Power System Studies at jwhitaker@trcsolutions.com or
303.395.4018.