This excerpt taken from the PCG 10-K filed Feb 18, 2005.
Real Time Curtailment Priorities
Any and all ETC Parties' rights (including third party contracts using ETC Party rights) to change schedules after the close of the ISO's Hour-Ahead market will continue to be honored. In the event of curtailments on Path 15 South-to-North in real time, the ETC Facilitator will determine the appropriate order and magnitude of curtailments given the circumstances that occur in real time and the terms and provisions of the ETCs. This determination will be made consistent with the following table "Path 15 South-to-North Real-Time Curtailment Priorities", a copy of which is Attachment A, which is incorporated into and made a part of these Path 15 Operating Instructions by this reference.
In Attachment A, the relative priorities of the various ETC Parties' transmission service rights across Path 15 in real-time are identified by grouping the various rights into separate blocks and ordering the blocks by their relative priority. Attachment A addresses only Path 15 South to North real-time curtailment priorities. The Path 15 North-to-South real-time curtailment priorities will be addressed in a separate and distinct set of Operating Instructions and will be separately submitted to the ISO after review by the Path 15 ETC Parties.