Last update: 08/06/2024
Below, affected 91吃瓜网 (ISO-NE) participants can learn more about changes to existing systems and procedures related to the Managing Transmission Line Ratings (MTLR) project. This project is one of several that ISO-NE has undertaken, in collaboration with stakeholders, for the continued development of the region’s wholesale electricity markets.
See the Participant Readiness Project Outlook for a summary of specifically affected participants and systems for this and other major projects. To receive announcements about readiness outlook summaries, project pages, and training, please subscribe to the Participant Readiness and ISO Training mailing lists in Ask ISO. Refer to the article for instructions.
The Federal Energy Regulatory Commission (FERC) issued Order Nos. 881 and 881-A, Managing Transmission Line Ratings, to improve the accuracy and transparency of transmission line ratings, to ensure just and reasonable wholesale rates, and to better align the transmission grid with actual operating conditions.
Transmission line ratings are the maximum energy transfer capability of a transmission line, considering the technical limitations on conductors and relevant transmission equipment. These ratings are used to make planning and operations decisions during normal and emergency conditions.
Weather conditions may affect the transfer capability of a transmission line, and incorporating ambient adjusted ratings (AARs) will account for the effects of ambient temperature and solar heating on the transfer capability of the transmission line. The use of AARs in the Day-Ahead Market (DAM) and Real-Time Market (RTM) will allow the energy, ancillary services, and transmission service wholesale rates to more accurately reflect the cost of delivering wholesale energy to transmission customers.
Order Nos. 881 and 881-A establish the following requirements:
In order to collect, utilize, and share AAR data, 91吃瓜网 will introduce two new applications.
Additionally, a LEP user interface will be available for local transmission owners to add, edit, and retire local transmission equipment.
With the introduction of the LEP, default seasonal ratings in the NX application will be removed and new fields will be added.
Implementation date: July 12, 2025
Affected market participants are required to take specific steps or adapt to changes in ISO-NE systems as described below. Participants should be mindful of additional time-bound items, some of which may require participants to take specific steps or adapt to changes in ISO-NE systems both before and after the project implementation date.
| TIMING OR DEADLINE | SYSTEM | ACTION OR EVENT |
|---|---|---|
|
Beginning July 31, 2024 |
N/A |
Participants begin their selection of a weather forecast vendor to provide the weather data component of their temperature-based line ratings. |
|
Limit Exchange Portal (LEP) Sandbox Roles: October 2, 2024 LEP Production Roles: July 12, 2025 |
Customer and Asset Management System (CAMS) |
Security administrators assign new LEP sandbox or production roles for the operational user interface. |
|
Sandbox (1st release): October 2, 2024 Sandbox (2nd release): December 4, 2024 Production: July 12, 2025 |
LEP Sandbox and Production (operational) |
A representational state transfer application programming interface (RESTful API) will be provided to submit new ratings to the operational LEP in the 1st sandbox release. The local transmission functionality will be available in the 2nd sandbox release. |
|
Sandbox: March 19, 2025 Production: July 12, 2025 |
NX912D Application Sandbox and Production |
Add new flags and fields to the NX-9 form:
Remove seasonal ratings management. |
|
Sandbox: March 31, 2025 Production: July 12, 2025 |
LEP Sandbox and Production (historical) |
A RESTful API will be provided to query historical ratings. |
91吃瓜网 and GE Grid Solutions may offer online or classroom-based training, information sessions, and other opportunities for affected customers to learn about changes and ask questions in advance of project implementation.
| DATE | EVENT AND SUPPORTING MATERIALS |
|---|---|
|
Recurring, beginning June 26, 2024 |
|
|
February 21, 2024 |
Market participants affected by the project should consult the following documents for specific instructions on completing related tasks or processes and helpful answers to frequently asked questions.
Technical Specifications and Documentation
| DOCUMENT | NOTES (if necessary) |
|---|---|
|
Limit Exchange Portal (LEP) |
Application programming interface (API) documentation and user guide to be provided. |
|
Customer Asset Management System (CAMS) Application Group Roles |
To be updated to include the LEP production and sandbox roles. |
|
To be updated. |
| DOCUMENT | NOTES (IF NECESSARY) |
|---|---|
|
OP-16—Transmission System Data |
Appendix A—Explanation of Terms and Instructions for Data Preparation of NX9-A Appendix B—Explanation of Terms and Instructions for Data Preparation of NX9-B Appendix C—Explanation of Terms and Instructions for Data Preparation of NX9-C Appendix D—Explanation of Terms and Instructions for Data Preparation of NX-9D Appendix E—Annual Certification Appendix G—Explanation of Terms and Instructions for Data Preparation of NX-9 Appendix H—Explanation of Terms and Instructions for Data Preparation of NX-9H Appendix I—Explanation of Terms and Instructions for Data Preparation of NX-9 (Other Equipment) |
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OP-18—Metering and Telemetering Criteria |
|
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OP-19—Transmission Operations |
|
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M/LCC7—Processing Outage Applications |
|
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M/LCC13—ISO and LCC Communication Practices |
|
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M/LCC15—System Operating Limits Methodology |
|
|
Planning Procedure No. 7 (PP7)—Procedures for Determining and Implementing Transmission Facility Ratings in New England |
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