1. NERC Congestion Management Congestion Management Option 3 Vendor Meeting Julie Pierce – NERC IDCWG Chair

2. Objectives • History of EI Congestion Management • Overview of IDC functionality • Overview of NERC TLR Procedure

3. Congestion- What is it? • A Few Power System Operator Answers: • “Overloading the Transmission System” • “Lines are on “Fire” • “Too Much Generation for the Load” • “Too Many MWs on the Lines • for the given Topology”

4. Congestion Management • Basic Methods Available • Re-Dispatch • Moving generation to change the flow of energy on the transmission system • Reconfiguration • Changing the topology of the transmission system to create the desired system flow

5. Output = 350 MW Load = 400 MW Line Limit = 400 MW Transmission Flow - MWs Maximum Output = 500 MW Generator A Generator to Load MWs for BA(s) (Not in MISO or PJM) Interchange Transactions (E-Tags) Market Flow for MISO and PJM Parallel Flow Caused by the Tags and GN to Ld

6. History – NERC Congestion Mngt • Prior to NERC Regional Congestion Management: • Localized Congestion Management Procedures used to mitigate the overloading of lines • Minimal number of operating agreements between NERC Reliability Regions • No visibility of Parallel Flows caused by all the MW transactions and local load serving taking place on the Eastern Interconnect

7. History – NERC Congestion Mngt • Visibility of Parallel Flows was increased with implementation of Electronic Tagging of MW transfers from on balancing area to another. • Implementation of E-tagging and NERC Policy 3 • In conjunction with this effort was the NERC Regional Congestion Management proof of concept

8. History – NERC Congestion Mngt • Idea was that Congestion Management should be done on a larger regional basis due to the interconnection characteristics and parallel flows present on the system • Assigning responsibility to those entities that were causing parallel flows was necessary to maintain reliability and equity during loading events

9. History – NERC Congestion Mngt • Transmission Loading Relief Procedure (TLR) • NERC Policy 9 and associated Appendices • Procedure defines several levels of transmission loading and mechanisms to remove MWs from the system. • Goal is to maintain reliability while removing MWs from the system in an equitable manner

10. History – NERC Congestion Mngt • Transmission Loading Relief (TLR) • Implemented in 1999 • Interchange Distribution Calculator (IDC) created • Adopted and used heavily by the majority of the Eastern Interconnect • Created Visibility of Eastern Interconnect MW Impacts due to Industry day to day business • Provided a useful analysis tool for Control Areas and Reliability Entities for Emergency and Non Emergency situations

11. Interchange Distribution Calculator • Basic Functionality • Impact Calculation of MW Transfers • Generation to Balancing Area Load • Scheduled Transfers from one Balancing Area to another • Define Responsibility For Loading events • Who’s MWs are on the transmission line(s) of interest • How Much Relief is Required? – Operator Input • Prescription for achieving relief using TLR Process Rules

12. Interchange Distribution Calculator • Basic Functionality (Continued) • Communications • Transmit Responsibilities and Relief Prescriptions to affected parties • Accept and display feedback • Allow Visibility and Transparency into the impact of potential MW transfers and actual taking place

13. IDC System Flow Diagram Request for Relief Flowgate Definition Prescription for relief Model of System IDC Current Outages Software Users: Reliability Market Flow from MISO/PJM Authorities and Balancing Areas ETAG Transactions

14. Transmission Loading Relief Summary of TLR Levels 1 - Warning 2 - Hold 3A - Reallocate Non-Firm 3B - Curtail Non-Firm/Halt Non-Firm Starting/Inc 4 - Reconfigure 5A - Reallocate Firm 5B - Curtail Firm 6 - Emergency 0 - TLR End

15. Congestion Management and Option 3 Calculating Impacts Of Visible Transfers Assigning Event Responsibility Option 3: Addresses New Method To assign Responsibility For loading events Defining Appropriate Relief Prescription Option 3: Addresses other Alternatives to Reliably and Economically get MWs off The system.

16. Questions ?