See the ISO New England Inc. Transmission, Markets, and Services Tariff, Attachment G—Procedure to Protect for the Loss of Phase II Imports, which describes the process used by ISO New England, New York ISO, and PJM to monitor their respective systems and provide the data required by ISO New England to calculate import limits on the Phase I/II high-voltage direct-current interconnection between it and Hydro-Québec TransÉnergie.
See ISO Express for a large selection of real-time and historical ISO data and reports on external interface limits—the defined limits for the points of connection between the New England power grid and a neighboring reliability coordinator’s power grid. Examples include: