WECC Position Paper for the ballot of Project 2007-01 – Underfrequency Load Shedding, being balloted July 24 – August 3, 2010
NERC is conductinga secondballot of standard PRC-006-1 – Underfrequency Load Shedding(Project 2007-01) from July 24 to August 3, 2010. If approved, the proposed PRC-006-1 will replace the existing PRC-006-0, PRC-007-0, and PRC-009-0.
WECC distributed a position paper for the first ballot of this standard on July 15, 2010, recommending a NO vote with comment. The NERC Underfrequency Load Shedding drafting team made changes to PRC-006-1 in response to comments submitted during the first ballot. WECC staff and several WECC subject matter experts have reviewed the revised PRC-006-1 standard and our recommendation to vote NO has not changed.
Members of the Project 2007-01–Underfrequency Load SheddingBallot Pool are encouraged to vote NO with comment to reject the proposed standard.
A complete copy of the proposed standard, associated materials, and the complete consideration of comments from the first ballot can be viewed at:
The primary concernidentified in the first position paper is that the proposal does not require coordination within individual interconnections.The current version of the standard would allow for all of the Planning Coordinators (PCs) within an interconnection to agree upon and implement a single coordinated plan, but it does not require it. As worded, the proposed standard would still allow for the possibility of as many different UFLS plans within an interconnection as there are Planning Coordinators. The standard still references islands that could form within the interconnection. There is no guarantee that islands that could form will form for all situations. The possibility of activation of multiple underfrequency programs intended to address islands that could form is problematic.Without the requirement to ensure coordination between the programs,if unanticipated islands form or no islands form,the result could be the activation of “competing” uncoordinated underfrequency load shedding programs for a single event. WECC believes that the standard should require a coordinated plan for each interconnection. Each interconnection has distinct characteristics that will require different plans. A single continent-wide performance characteristic could be achieved by different coordinated interconnection plans. This would allow all the PCs within WECC to adopt the existing WECC Coordinated Off-Nominal Frequency Load Shedding and Restoration Plan, modified as may be necessary to meet the continent-wide performance curves of the continent-wide standard. This would ensure continued coordination for underfrequency events within the Western Interconnection.
There has been some confusion regarding the initial WECC vote for PRC-006-1. The initial WECC position paper recommended a NO vote, but an affirmative vote was cast by WECC. This was due to an error in balloting. WECC had intended to vote No with comment. WECC attempted to withdraw the affirmative vote, but we were told we could not. WECC will be voting negative in this second ballot. We apologize for any confusion this may have caused.
All WECC entities that are registered in the Project 2007-01–Underfrequency Load Shedding Ballot Pool are urged to cast their ballots prior to the close of the ballot period. If you determine that you will vote NO, it is important that you provide a comment with your vote indicating the reason(s) why you voted NO. The NERC Standards Development Procedure requires the Underfrequency Load Sheddingdrafting team to respond to any negative votes with comment and to conduct a recirculation ballot.
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