***** EXTERNAL email. Please be cautious and evaluate before you click on links, open attachments, or provide credentials. ***** PGDTF: The attached is FYI. [cid:image001.png@01D41853.81CDFE20] A. Benjamin Richardson, P.E.(Colorado) System Development - Transmission Planning 2705 West Lake Drive Taylor, TX 76574 O: 512-248-4505 | M:720-470-3643 From: Richardson, Ben Sent: Tuesday, July 10, 2018 1:49 PM To: Dylan Preas <[log in to unmask]>; Weatherly, Joe <[log in to unmask]>; Loyferman, Larisa M. <[log in to unmask]>; Juricek, Michael <[log in to unmask]> Cc: Borkar, Sandeep <[log in to unmask]> Subject: Why we should seriously consider examining losses based on more than 1 GMD orientation Team (feel free to pass this e-mail around): Justification to examine more than 1 orientation: 1. Please read (less than 1 page of reading) Section 3.3 of NERC GMD Planning Guide: https://urldefense.proofpoint.com/v2/url?u=https-3A__www.nerc.com_comm_PC_Geomagnetic-2520Disturbance-2520Task-2520Force-2520GMDTF-25202013_GMD-2520Planning-2520Guide-5Fapproved.pdf&d=DwIFAg&c=trp9rTvIdyEWh1VWB5x8_2JiPaB5oGZOtWPDws2_VoY&r=LSCEyADss-GLNJicW8iG5D5hJ2MBK7jaKKau346v3cs&m=xABc8CNpua-TORt1mr0o3jI7YuPKdtp_bXFsZiGaIvo&s=jJOhhIU4xVykPMfRQeJcumFzDP5I1B0M77dTOCUYXX0&e= 2. Notice the NERC time-series data for the benchmark event is provided with data points at 10 second intervals for a 30 hour event. Within most of those 10 second intervals the storm changes orientation significantly. For example from time point 56,590 seconds to 56,600 seconds, a 10 second interval, the storm changes orientation by 178 degrees. You can find this 10 second 30 hours Excel data on NERC's website under Benchmark GMD Event in this location: https://urldefense.proofpoint.com/v2/url?u=https-3A__www.nerc.com_comm_PC_Pages_Geomagnetic-2DDisturbance-2DTask-2DForce-2D-28GMDTF-29-2D2013.aspx-3FView-3D-257B2411fa34-2D593e-2D4b21-2Dbe7a-2D245dcb384c5d-257D-26SortField-3DDate-26SortDir-3DDesc&d=DwIFAg&c=trp9rTvIdyEWh1VWB5x8_2JiPaB5oGZOtWPDws2_VoY&r=LSCEyADss-GLNJicW8iG5D5hJ2MBK7jaKKau346v3cs&m=xABc8CNpua-TORt1mr0o3jI7YuPKdtp_bXFsZiGaIvo&s=RPALk0gGnccBLOaq4xz11jGiNDAcCNcT9cDiJ_t9g3Y&e=<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.nerc.com_comm_PC_Pages_Geomagnetic-2DDisturbance-2DTask-2DForce-2D-28GMDTF-29-2D2013.aspx-3FView-3D-257b2411fa34-2D593e-2D4b21-2Dbe7a-2D245dcb384c5d-257d-26SortField-3DDate-26SortDir-3DDesc&d=DwIFAg&c=trp9rTvIdyEWh1VWB5x8_2JiPaB5oGZOtWPDws2_VoY&r=LSCEyADss-GLNJicW8iG5D5hJ2MBK7jaKKau346v3cs&m=xABc8CNpua-TORt1mr0o3jI7YuPKdtp_bXFsZiGaIvo&s=rGEl9SNIdkIvVXakEBTvRufy8ogAh8DxBiScK2ZmyVs&e=> Conclusion. If we expect outages to produce multiple system topologies during a presumed 30 hour event, we are also likely to experience system reactive losses that are very different than system reactive losses that are produced by a base case with all facilities in-service. This is the point I was attempting to communicate yesterday during our discussion of Orientation 2 in the draft Vulnerability Assessment Scope. I walked away feeling that Mick Juricek understood this point clearly but not feeling like others did. Whether you agree that we should examine losses for more than 1 orientation or not, I hope this will at least clarify why I am concerned. [cid:image001.png@01D41853.81CDFE20] A. Benjamin Richardson, P.E.(Colorado) Transmission and Interconnection Studies 2705 West Lake Drive Taylor, TX 76574 O: 512-248-4505 | M:720-470-3643 ######################################################################## To unsubscribe from the PGDTF list, click the following link: http://lists.ercot.com/scripts/wa-ERCOT.exe?SUBED1=PGDTF&A=1