1. Texas Nodal http://nodal.ercot.com 1 Nodal Telemetry Outreach and Recent Changes to Focused Input Testing (FIT) NATF Sep 29, 2009 Stacy Bridges, ERCOT

2. Texas Nodal http://nodal.ercot.com 2 Recent Changes to FIT Testing Nodal Telemetry Outreach Remaining FIT III Windows in 2009 Nodal Telemetry Outreach and Recent Changes to FIT Testing

3. Texas Nodal  ERCOT discontinued making ERCOT-side Manual Replacements (MRs) during the FIT III Week 15 Window (Sept 8 – 10).  During the first two days of the test (Sep 8, 9), ERCOT provided ERCOT-side MRs to support State Estimator solutions.  On the third day of the test (Sep 10), ERCOT discontinued MRs (see details on next slide). http://nodal.ercot.com 3 Recent Changes to FIT Testing

4. Texas Nodal  On Sept 10, ERCOT discontinued ERCOT-side MRs for the first time during a FIT window.  The ERCOT State Estimator (SE) continued to solve during test hours with convergence rates comparable to those achieved during previous FIT windows.  Factors contributing to this success included:  Code enhancements that deployed to the Nodal production environment in August  ICCP updates that were recently submitted by Market Participants (MPs)  Robustness of the SE software http://nodal.ercot.com 4 Recent Changes to FIT Testing On Sept 10, ERCOT discontinued making MRs for Nodal telemetry.  The SE convergence performance on Sept 10 promoted confidence that the software has matured to a point that ERCOT may continue to conduct future FIT windows without the need to facilitate SE solutions via ERCOT-side MRs.

5. Texas Nodal 10/2/2015 FIT Series WeekDateDay 1Day 2Day 3Convergence Avg % for all Test Hours 100% Convergence Achieved FIT IIIWeek 1Feb 24 – 26, 200975.4578.8692.8582.3909 of 27 hrs Week 2Mar 10 – 12, 200996.8292.9798.4196.0720 of 27 hrs Week 3Mar 24 - 26, 200985.4594.9894.7091.7114 of 27 hrs Week 4Apr 07 - 09, 200997.1392.6097.4495.7221 of 27 hrs Week 5Apr 21 – 23, 200987.4789.8795.6591.0008 of 27 hrs Week 6May 05 – 07, 200994.3494.4791.8793.5613 of 27 hrs Week 7May 19 – 21, 200996.8197.3697.0497.0718 of 26 hrs* Week 8Jun 02 – 04, 200988.4784.0993.2988.6210 of 27 hrs Week 9Jun 16 – 18, 200997.4586.1495.5993.0613 of 27 hrs Week 10Jun 30 – Jul 2, 200994.9189.8986.6690.4911 of 27 hrs Week 11Jul 14 – 16, 200991.0184.7097.4991.0614 of 27 hrs Week 12Jul 28 – 30, 200995.9194.7393.6694.7718 of 27 hrs Week 13Aug 11 – 13, 200994.7294.6597.3795.5819 of 27 hrs Week 14Aug 25 – 27, 200996.5193.2599.0796.2821 of 27 hrs Week 15Sep 08 – 10, 200990.6010096.3395.6421 of 27 hrs Week 16Sep 22 – 24, 200989.4299.0796.3094.9320 of 27 hrs Recent Changes to FIT Testing – FIT III Trends to Date 5 * One hour was removed from the Week 7 test results to accommodate a nodal database load.No Manual Replacements Recent convergence percentages provide a good indication of SE solution capability, but more work is still needed in the areas of missing unit telemetry and measurement quality.

6. Texas Nodal  To date, the outreach effort has focused primarily on Market Participants who were missing the largest share of ICCP points in Nodal.  ERCOT teams are now preparing to work with MPs to address a broader scope of missing points and to clean-up issues.  The ERCOT Advanced Network Applications, ICCP, Client Services, and EDS teams have scheduled a series of weekly internal meetings through the end of 2009 to discuss outreach progress and to coordinate follow-ups with MPs.  Follow-ups include specific open ICCP issues that will be routinely communicated with MPs on an individual basis and coordinated with the FIT windows. http://nodal.ercot.com 6 Nodal Telemetry Outreach ERCOT began a Nodal Telemetry Outreach on August 31, 2009 to help MPs to correct Nodal telemetry issues in time for market trials.

7. Texas Nodal  As the telemetry outreach effort progresses, the quality of measurements used in each SE solution is expected to improve, along with overall confidence in SE solutions.  Information regarding the outreach effort and upcoming FIT windows will continue to be communicated via market notices, stakeholder meetings, and the regularly scheduled EDS market calls (http://www.ercot.com/committees/nodal/eds/).http://www.ercot.com/committees/nodal/eds/ http://nodal.ercot.com 7 Nodal Telemetry Outreach MPs may submit questions about the telemetry outreach to EDS3@ercot.com with “Nodal Telemetry Outreach” in the subject line.EDS3@ercot.com

8. Texas Nodal http://nodal.ercot.com 8 The 2009 FIT III Calendar and FIT III Assessment reports are posted at: http://nodal.ercot.com/readiness/eds3/documents/index.html Remaining FIT III Windows in 2009 Name of FIT III TestTesting DatesPublishing Dates for FIT Report FIT III, Wk 17Oct 06 – 08Oct 20 FIT III, Wk 18Oct 20 – 22Nov 03 FIT III, Wk 19Nov 03 – 05Nov 17 FIT III, Wk 20Nov 17 – 19Dec 01 FIT III, Wk 21Dec 01 – 03Dec 15 FIT III, Wk 22Dec 15 – 17Jan 03