1. NERC Congestion Management Congestion Management
Option 3
Vendor Meeting
Julie Pierce NERC IDCWG Chair
2. 2 Objectives History of EI Congestion Management
Overview of IDC functionality
Overview of NERC TLR Procedure
3. 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. 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. 5 Transmission Flow - MWs Taking this simple case one step further, if we assume a generator output of 350 megawatts to serve a 400 megawatt load with a 50 MW import
And the transmission corridor has 400 megawatts of transfer, and we will show that is due to other contracts flowing on the system.Taking this simple case one step further, if we assume a generator output of 350 megawatts to serve a 400 megawatt load with a 50 MW import
And the transmission corridor has 400 megawatts of transfer, and we will show that is due to other contracts flowing on the system.
6. 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. 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. 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. 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. 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. 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
Whos 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. 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. 13 IDC System Flow Diagram
14. 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. 15 Congestion Management and Option 3
16. 16
