PGDTF:

 

The attached is FYI.

 

 

 

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://www.nerc.com/comm/PC/Geomagnetic%20Disturbance%20Task%20Force%20GMDTF%202013/GMD%20Planning%20Guide_approved.pdf

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://www.nerc.com/comm/PC/Pages/Geomagnetic-Disturbance-Task-Force-(GMDTF)-2013.aspx?View={2411fa34-593e-4b21-be7a-245dcb384c5d}&SortField=Date&SortDir=Desc

 

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.

 

 

 

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