All,
Following are the responses from Mark Olson, NERC lead on GMD planning activities, to questions on the requirements for the transformer thermal impact assessment and GMD Vulnerability Assessment required by TPL-007-1.  Ian Grant and Emanuel Bernabeu are the current leaders of the NERC GMDTF, and Emanuel served the standard drafting team that developed TPL-007-1. The flow chart was extracted from the Application Guidelines which is part of the Standard.  We will be discussing his responses at the July 9th PGDTF meeting.  Please review them and be prepared to discuss them at the PGDTF meeting?
Thanks,
Mike

From: Mark Olson [mailto:[log in to unmask]]<mailto:[mailto:[log in to unmask]]>
Sent: Monday, June 25, 2018 11:48 AM
To: Juricek, Michael
Cc: Grant, Ian S; Bernabeu, Emanuel E.; Loyferman, Larisa M.
Subject: RE: Questions from Geomagnetic Disturbance Task Force Meeting (GMDTF) | June 13, 2018 - Charlotte, NC

Hi Michael- thanks again for joining the GMDTF meeting and providing an update on the work that PGDTF is doing. We became pressed for time during the morning session and weren’t able to have more dialogue on your topics. I discussed with Emanuel and Ian afterward that we may want to look for another opportunity to do a web meeting dedicated to TPL-007 implementation, particularly since we are in an active time with the GIC studies.
Here are my responses to your questions…Ian and Emanuel can add their perspectives as they think is needed. -Mark
GIC System Models quickly become stale during 60-Month GMD Vulnerability Assessment period. I understand your concern, and some areas are changing more rapidly than others. I think this is a good topic for further discussion/best practices. But the standard is intended to identify risk of voltage collapse from a rare, extreme event. The standards drafting team viewed the 5-year periodicity as appropriate for obtaining a reasonable vulnerability assessment. More frequent assessments can be done by the planning entities.
Should the same GIC System Models be used for the GIC calculation for the transformer thermal impact assessment and GMD Vulnerability Assessment?  If the TOs and GOs use all 24 months allowed by the standard for their transformer thermal impact assessment, the GIC System Models will be out-of-date when the GMD Vulnerability Assessment is started. When the standard was written, I believe the SDT envisioned the same GIC system model would be used throughout the vulnerability assessment process, including the transformer thermal assessment. The diagram of the GMD Vulnerability Assessment process (in the application guidelines section of the standard, pasted below) implies this. I think this is also a good topic for further discussion with other entities, to understand the extent of the problem in areas and ways to address it. For instance, could updated GIC calculations be obtained when system configuration changes during the GMDVA, which would support engineering judgement of changes to transformer risk.
Is the transformer thermal impact assessment part of the GMD Vulnerability Assessment or a separate assessment? Transformer thermal impact assessment should be considered part of the GMDVA (the definition includes damage to equipment). The diagram in the application guidelines section is intended to show including transformer thermal impacts in the assessment process.


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_____________________________
Mark Olson
Senior Engineer, Reliability Assessments
North American Electric Reliability Corporation
3353 Peachtree Road NE, Suite 600 – North Tower
Atlanta, GA 30326
404-446-9760 office | 404-801-5536 cell
[log in to unmask]<mailto:[log in to unmask]>
Reliability | Accountability
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From: Juricek, Michael [mailto:[log in to unmask]]<mailto:[mailto:[log in to unmask]]>
Sent: Tuesday, June 19, 2018 3:16 PM
To: Mark Olson <[log in to unmask]<mailto:[log in to unmask]>>
Cc: Grant, Ian S <[log in to unmask]<mailto:[log in to unmask]>>; Bernabeu, Emanuel E. <[log in to unmask]<mailto:[log in to unmask]>>; Loyferman, Larisa M. <[log in to unmask]<mailto:[log in to unmask]>>
Subject: Questions from Geomagnetic Disturbance Task Force Meeting (GMDTF) | June 13, 2018 - Charlotte, NC

Mark,
No one at the GMDTF meeting responded to the following concerns/questions about the GIC System Models to be used for TPL-007-1.

•         GIC System Models quickly become stale during 60-Month GMD Vulnerability Assessment period.

•         Should the same GIC System Models be used for the GIC calculation for the transformer thermal impact assessment and GMD Vulnerability Assessment?  If the TOs and GOs use all 24 months allowed by the standard for their transformer thermal impact assessment, the GIC System Models will be out-of-date when the GMD Vulnerability Assessment is started.

•         Is the transformer thermal impact assessment part of the GMD Vulnerability Assessment or a separate assessment?
The ERCOT PGDTF will appreciate any guidance we can get on these questions.
Thanks,
Michael Juricek, P.E.
Senior Manager, Transmission Planning
Assets Planning Distribution and Transmission
Oncor Electric Delivery Co LLC
Office: 214.743.6671
Mobile: 214.490.0748





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