Notification of revised ISO operating procedures 2510, 3200A, and 4120

The California ISO (ISO) has updated the procedures referenced below.

2510 NERC (North American Electric Reliability Corporation) and CAISO Tagging Requirements, version 10.4, effective Sep 17, 2026.

Added Section 3.2.2 for Extended Day Ahead Market (EDAM) tagging Transfer System Resources (TSRs). Added examples of Misc. token information required for both MasterFile registered and Transient TSRs. Updated Operationally Affected Parties section to reflect “CAISO” Public. Minor formatting and grammar edits and removed history prior to five years.

3200A Operations for Extreme Weather, version 1.1, effective Sep 17, 2026.

Annual Review: Removed links to internal documents other than those listed in References section to avoid public confusion. Added “Playbook: Summer Readiness – Home” to References with link for internal access. No other content changes required.

4120 Gas Transmission Pipeline System Limitations or Outages, version 8.2, effective Sep 17, 2026.

Added the requirement to block all gas resources in the given Gas Nomogram from receiving Ancillary Service awards during the Gas Nomogram activation period. Minor format and grammar edits and removed history prior to five years.

The ISO’s operating procedures are available on the Operating Procedures webpage.

Please contact the CAISO/RC West Procedure Control Desk at ProcedureControl@caiso.com with any questions.