1. Jerry Rust Chair - Underfrequency Load Shedding Criterion Team
WECC Regional Criterion PRC-006-WECC-CRT-1 (Project WECC-0065) Underfrequency Load Shedding Criterion
September 9, 2011

2. PRC-006-WECC-CRT-1 Purpose of UFLS Background Current Situation
Purpose of PRC-006-WECC-CRT-1
Proposed Criteria
Implementation
Next Steps

3. PRC-006-WECC-CRT-1
Last automatic protection scheme to arrest the frequency decline after a disturbance
Load Shedding Occurs;
Frequency decline was arrested; and,
Recovery was observed.

4. Background - PRC-006-WECC-CRT-1
July 2 & 3, 1996 and August 10, 1996 Western Interconnection wide disturbances
WECC Disturbance Report
Complete review of the Underfrequency load shedding programs
Coordination with generator off-nominal frequency protection requirements
Coordination of automatic and manual load restoration
Coordination between and within sub-regions of the Western Interconnection

5. Background - PRC-006-WECC-CRT-1
November 8, 1996 ad hoc Underfrequency Issues Work Group (UIWG) formed
Determine if a uniform UFLS program can be specified for all of WECC
If yes, recommend a uniform off-nominal frequency program
Recommend a policy regarding the automatic restoration of load
Recommend a policy regarding intentional tripping of tie lines and generators due to underfrequency

6. WECC 2009 Goals for UFLS
The Western Electricity Coordinating Council Operating and Planning Committees have established a joint goal to review the effectiveness of the design and implementation of the WECC Coordinated Off-Nominal Frequency Load Shedding and Restoration Program

7. WECC 2009 Goals for UFLS WECC UFLS – Test Effectiveness
Review of frequency set points
Review of Generator tripping set points
Review of Automatic Restoration
Address the NERC registered entities – Correct Entities and inventory
Consistent with PRC standards – Gen Standards
Address Variable Generation
Full and detailed documentation
Southern Island Load Tripping Plan
NWPP UFLS Plan
Others

8. WECC 2009 Approach for UFLS Inventory Topology (variable generation)
Simulate
Various Cases
Solve for Worst Case Contingency
Recommended Changes if Necessary

9. WECC 2009 Time-Frame for UFLS
Findings October 2009
Changes if Necessary
Recommendations October 2009
Full and detailed documented Plan – First quarter 2010 (if not sooner)

10. WECC 2009 Findings for UFLS
Over 200 simulations utilizing the existing inventory of relay and associated armed load verifies the following:
Load Shedding Occurs;
Frequency decline was arrested; and,
Recovery was observed.
The WECC plans still performed under simulation as originally designed.

11. Purpose - PRC-006-WECC-CRT-1
NERC PRC is categorized as a fill-in-the-blank standard.  The WECC Board of Directors has instructed WECC to utilize the Process for Developing and Approving WECC Standards whenever drafting criteria to meet NERC fill-in-the-blank requirements and to categorize the resultant work product as a criterion under the WECC Document Categorization procedures. 

12. Goals - PRC-006-WECC-CRT-1
No Changes to Existing Plan
Consolidate the Existing Plan
Define how to implement Existing Plan
Develop timelines to NERC requirements
Define responsible entities

13. Consolidation - PRC-006-WECC-CRT-1
WECC Coordinated Plan - consolidated 12 pages, approved 1st quarter 2011 by the OC and PCC, approved by WECC Board of Directors 2nd quarter 2011
WECC Coordinated Plan recognizes sub-plans, such as NWPP and SILT
No changes to the existing plan

14. Consolidation - PRC-006-WECC-CRT-1
WECC Coordinated Plan first level of underfrequency load shedding occurs at 59.5 Hz (SILT) next at 59.3 Hz (NWPP) and then 59.1 Hz (the remaining WECC)
WECC Coordinated Plan may be changed in accordance with WECC process
WECC Coordinated Plan currently meets NERC Reliability Standards

15. PRC-006-WECC-CRT-1
The WECC JGC established the requirement for a UFLS “Review Group”
A joint regional group comprised of WECC Balancing Authorities, Planning Coordinators, Transmission Operators, and Transmission Planners created by the WECC Joint Guidance Committee to review and maintain an accurate underfrequency load shedding database and simulation models reflecting the WECC Off-Nominal Frequency Load Shedding Plan.
WECC Review Group to receive the required information and assure WECC Coordinated Plan performs under simulation as designed

16. PRC-006-WECC-CRT-1
Underfrequency load shedding entities (UFLS Entities) shall mean all entities that are responsible for the ownership, operation, or control of UFLS equipment as required by the Coordinated Plan. Such entities may include one or more of the following:
Transmission Owner
Distribution Provider

17. PRC-006-WECC-CRT-1
BA peak load is armed in accordance with WECC Coordinated Plan
BA to allocate its historical peak load to TOPs
TOPs must identify which sub-area Coordinated Plan they are following (e.g. NWPP, SILT, or WECC)
TOPs or its agent to coordinate with UFLS Entities to assure underfrequency relays are in place and armed in accordance with the WECC Coordinated Plan

18. PRC-006-WECC-CRT-1
The criterion allows for flexibility of various combinations of the UFLS Entities to meet the requirements and fulfill the WECC Coordinated Plan

19. PRC-006-WECC-CRT-1
Each Transmission Operator or its agent shall produce documentation showing how it coordinated implementation of each sub-area Coordinated Plan of the Coordinated Plan with its UFLS Entities. Documentation may include, but is not limited to, evidence of how the adopted sub-area Coordinated Plan of the Coordinated Plan is implemented among the TOP and the UFLS Entities.

20. PRC-006-WECC-CRT-1
Each UFLS Entity or its agent shall coordinate and provide documentation of its responsibilities in meeting the Coordinated Plan to the Review Group. Documentation shall include:
A listing of its responsibilities as required under the Coordinated Plan.
A designation of the agent responsible for all data submission to demonstrate compliance with the Coordinated Plan

21. PRC-006-WECC-CRT-1
Each UFLS Entity or its agent shall compile their respective Coordinated Plan data and dynamics file in the WECC-defined format, as listed in the Coordinated Plan – Data Submittals Requirements (Attachment B of this criterion), for its entire load and annually, by June 1, submit Attachment B to the Review Group and to the UFLS Entity’s respective Transmission Operator.

22. PRC-006-WECC-CRT-1
Each Generator Owner shall annually compile and submit to the Review Group, no later than June 1, their respective Coordinated Plan data and dynamics file for its generation, in the format defined in Attachment B of this criterion.

23. PRC-006-WECC-CRT-1
The Review Group to coordinate and perform all post-event analyses associated with the Coordinated Plan.

24. Time-Frame PRC-006-WECC-CRT-1
It is anticipated that this document will be ready for WECC standing committee and Board of Director approval in time to be effective on January 1, If the necessary approvals are received in time for an effective date of January 1, 2012, the following dates will be enforced:
Balancing Authority shall meet R5 for the first time on June 1, 2012
UFLS Entities shall meet R9 for the first time on June 1, 2012.

25. Time-Frame PRC-006-WECC-CRT-1
Generator Owners will meet R12 for the first time on June 1, 2012.
The Review Group will complete the first annual review of the Coordinated Plan by November 1, 2012.
If the necessary approvals are not obtained in time for this criterion to become effective on January 1, 2012, then the dates above will be incremented to 2013.

26. Questions?

27. PRC-006-WECC-CRT-1
Level 1 32 pt
Level 2 28 pt
Level 3 24 pt

28. PRC-006-WECC-CRT-1
Level 1 32 pt
Level 2 28 pt
Level 3 24 pt