DYNAMIC SCHEDULES AD HOC WORK GROUP ANN DAVIS, CHAIR MARILYN FRANZ

DYNAMIC SCHEDULES AD HOC WORK GROUP DriversIssues Example of current Dynamic Scheduling Work Group Members – Dynamic Scheduling Experience Wanted Chair Contact Information

Drivers for Considering Tagging Dynamic Schedules WEBSAS – Business Practice 18 WIT requirements –Need transactions impacting Scheduled Net Interchange –Integrate into hourly values Common implementation within WECC

Drivers for Considering Tagging Dynamic Schedules Ready to influence NERC Dynamic Scheduling Work Group CISO requirement Is tagging the answer for handling Dynamic Schedules?

Issues Surrounding Tagging Dynamic Schedules Clarification of terminology within WECC - Dynamic Transfer vs. Dynamic Schedule –Are Pseudo Ties part of the problem in USF Should reserve sharing group energy deliveries be tagged? –NERC Policy 3.A.2.1 clarification: Interchange transactions established to replace unexpected generation loss, such as through prearranged reserve sharing agreements…exempt from tagging for 60 minutes…. Differing interpretations exist.

Issues Surrounding Tagging Dynamic Schedules Should the energy profile always be maximum amount? Should the tag be updated during the hour? How often? Different process for different types? –Remote Generation Needs –Ancillary Services Needs After the hour is complete, the tag can not always be updated with the integrated energy (60 minute limitation). Costs of transferring signal directly to WIT and WebSAS

Dynamic Transfer with Multiple Participants Example: Generator has a 500 MW output This schedule is generated utilizing a dynamic schedule that is calculated on a Real Time basis every four seconds throughout the hour This schedule is divided among five participants A percentage of the schedule is divided between the participants and calculated Real Time

4 seconds The dynamic schedule is calculated every four seconds & sent to Participants by data link from Source Control Area Real Time Dynamic Schedule Dynamic Transfer Generator 500 MW After the Hour = Integrated Hourly Schedule Calculated and sent by data link by Source Control Area Controls AGC There is NO imbalance! Dynamic at the top of the hour is 500MW Real Time: Each participants AGC is adjusted every 4 seconds during the hour 4 seconds C 125MW B 75MW A 125MW D 75MW E 100MW

4 seconds The dynamic schedule is calculated every four seconds & sent to Participants by data link from Source Control Area Real Time Dynamic Schedule Reduced Dynamic Transfer Generator 250 MW C 75MW B 50MW A 50MW D 25MW E 50MW After the Hour = Integrated Hourly Schedule calculated and sent by data link by Source Control Area There is NO imbalance! Plant goes to 250MW at the half Each Participants AGC is adjusted every 4 seconds during the hour matching the Reduced Generator output 4 seconds

Final Result On the half the unit went down to 250MW Reduced Generator Output is calculated every 4 seconds 500 X 30 / 60 = X 30 /60 = 125 End of the hour = = 375 After the Hour = Integrated Hourly Schedule = 375 Controls AGC There is NO imbalance! 4 seconds Generator 250 MW All participants were notified of their reduced share All Control Areas checked out to integrated number

Advantages to Existing Dynamic Scheduling The Dynamic schedule will change throughout the hour due to plant fluctuations AGC automatically responds to the fluctuations If the schedule is reduced, everyones percentage or share is reduced After the hour, an integrated hourly schedule is created automatically by the EMS system The schedule is automatically populated Each participating control area is required to have their equipment set up to automatically send or receive dynamic signals Minimal manual input

Tagging Limitations to Consider Present Tagging of Dynamic schedules does not work. Tagging timeframe does not allow for after the hour changes Each hour a tag would have to be updated with the before the hour – estimated schedule Each hour a tag will have to be updated with the after the hour dynamic value, if possible Dynamic tags presently do not affect the tag driven scheduling systems, thus cannot affect AGC (signal affects intra-hour). A tag cannot be changed Real Time every four seconds

Additional Dynamic Schedule Issues

Proposed Ad Hoc Workgroup Group members should currently be involved with implementing dynamic schedules Determine and come to consensus on any issues related to handling possibly tagging dynamic schedules. Strive for consistent implementation throughout WECC Propose any necessary Business Practices Review any existing WECC documents related to Dynamic Schedules and Remote Generation (2) Representation in NERC Dynamic Scheduling Work Group

DYNAMIC SCHEDULES AD HOC WORK GROUP Current Volunteers: Ann Davis, Chair –Sheryl Torrey/Jennella Battles –Jim Hansen –Sue Holden-Baker –Marilyn Franz

DYNAMIC SCHEDULES AD HOC WORK GROUP Additional Volunteers

DYNAMIC SCHEDULES AD HOC WORK GROUP Contact Chair with questions/issues: –Ann Davis – BPAT Plan to hold a meeting in December