1. Project 2007-01 Underfrequency Load Shedding PRC-006, 007 and 009 Bob Millard ReliabilityFirst staff Reliability Standards Workshop April 29-30, 2008

2. NERC Standards Workshop 4/29, 30/08 2 Overview Underfrequency Load Shedding Project 2007-01  Revise 3 standards related to Underfrequency Load Shedding (UFLS): PRC-006: Develop & Document Regional Reliability Organization UFLS Program PRC-007: Assure Consistency with Regional UFLS Programs PRC-009: Analyze & Document UFLS Performance Following an Underfrequency Event Note: PRC-008, UFLS Maintenance & Testing was transferred to Project 2007-17

3. NERC Standards Workshop 4/29, 30/08 3  Dana Cabbell — Southern California Edison Co. (Chair)  Paul Attaway — Georgia Transmission Corporation  Brian Bartos — Banders Electric Cooperative  Larry E. Brusseau — Midwest Reliability Organization  Jonathan Glidewell — Southern Co. Transmission  Geral Keenan — Bonneville Power Administration  Robert W. Millard — ReliabilityFirst Corporation UFLS SDT Roster Underfrequency Load Shedding Project 2007-01

4. NERC Standards Workshop 4/29, 30/08 4  Steven Myers — Electric Reliability Council of Texas  Mak Nagle — Southwest Power Pool  Robert J. O'Keefe — American Electric Power  Philip Tatro — National Grid  Robert Williams — Florida Municipal Power Agency  David Taylor — NERC UFLS SDT Roster (Continued) Underfrequency Load Shedding Project 2007-01

5. NERC Standards Workshop 4/29, 30/08 5 Objective Underfrequency Load Shedding Project 2007-01  Eliminate “fill-in-the-blank” characteristics RRO responsibilities (currently present in PRC-006)  Determine whether UFLS “program” requirements should be continent-wide and/or regional (related to PRC-006 and 007) Consider effectiveness & infra structure existing Consider implementation concerns  Determine how to address event reporting (currently in PRC-009)

6. NERC Standards Workshop 4/29, 30/08 6 Current Direction Underfrequency Load Shedding Project 2007-01  Various combinations of “load steps” & “frequency set points” can achieve objective.  Current programs repeatedly studied for effectiveness.  Changing to one “program” would take time & money.  APPROACH - Identify performance characteristics/requirements for developing regional reliability standards.

7. NERC Standards Workshop 4/29, 30/08 7 Regional Performance Requirements Underfrequency Load Shedding Project 2007-01  Direct development of Regional Standards for implementing automatic UFLS to arrest & recover declining system frequency. Each Regional Standard shall address the following UFLS performance requirements: Frequency decline shall be arrested at no less than 58.0 Hz. Frequency shall not remain below 58.5 Hz for greater than 10 seconds, cumulatively, and shall not remain below 59.5 Hz for greater than 30 seconds, cumulatively.

8. NERC Standards Workshop 4/29, 30/08 8 Regional Performance Characteristics Underfrequency Load Shedding Project 2007-01 Frequency overshoot resulting from operation of UFLS relays shall not exceed 61.0 Hz for any duration and shall not exceed 60.5 Hz for greater than 30 seconds, cumulatively. Bulk Electric System voltage during and following UFLS operations shall be controlled such that the per unit Volts per Hz (V/Hz) will not exceed 1.18 for longer than 6 seconds cumulatively, and will not exceed 1.10 for longer than 1 minute cumulatively. Functional Entities responsible for developing, analyzing and implementing the “program” shall be identified.

9. NERC Standards Workshop 4/29, 30/08 9 Current Direction Underfrequency Load Shedding Project 2007-01  Analysis & reporting of an “event” is not unique to UFLS  Past standards required “event” information be submitted to NERC  ERO responsible for System oversight  APPROACH – Administer “event” through ERO Rules of Procedure and relationship with Regional Entities

10. NERC Standards Workshop 4/29, 30/08 10 Status & Schedule  Draft standard ready to post for 45 day comment period  Response to comments and repost as appropriate  Provide direction for development of Regional Standards early 2 nd quarter 2008  Propose completion of Regional Standards approximately 18 months later  Process through NERC and FERC – available for formal implementation 2 – 2 ½ yrs from now

11. NERC Standards Workshop 4/29, 30/08 11 Questions? Underfrequency Load Shedding Project 2007-01 11  Dana Cabbell (Chair), Southern California Edison Co. dana.cabbell@sce.com  David Taylor, NERC Standards Coordinator David.Taylor@nerc.net