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Bob Thomas

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Illinois Municipal Electric Agency

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1) Subsequent to a review performed by NERC staff, the SDT has reformatted and modified certain requirements of the draft PRC-006-RFC-01 standard. Do you agree with the reformatted structure and modified requirements of the standard?

No

1) If not, please provide specific suggestions.

IMEA supports comments submitted by Indiana Municipal Power Agency and First Energy.
 
If RFC decides to proceed with a proposed Region-specific UFLS reliability standard, IMEA would appreciate the SDT’s consideration of the following comments.
 
Please identify the origin and definition of “Year One Peak Demand” in R1.1 and R2.1.
 
 
Please explain the rationale for dropping language allowing for DP aggregation of load with other DPs to implement a collective UFLS program.
 
IMEA believes clarification is needed in the intent of the language of R1.1 and R2.1.  The current language could be interpreted to require a DP to shed at least 25% of the peak load amount regardless of the load conditions at the time of the UFLS event.  Under this interpretation, a DP with wide variance in load and a limited number of feeders (e.g., less than 10 feeders) could be required to drop all or most of its customers in order to “Shed at least 25 percent of the Load by implementing the Load shedding based on the Year One Peak Demand.”  For example, a peak summer load of 41 MW would require shedding at least 10.3 MW of load in order to meet the 25% of peak.  The average load for this system is 13 MW and the minimum load is 8.9 MW, which means this system would be required to trip 8 of 9 circuits or all 9 circuits depending on the load at the time of the UFLS event.  In order to avoid this misinterpretation, the following language change is recommended for R1.1 and R2.1:  “Shed at least 25 percent of the Load by implementing the Load shedding on those feeders that, in aggregate, serve at least 25 percent of the entity’s load during the designated annual peak hour based on the Year One Peak Demand.  IMEA recommends that an attachment be included with this proposed reliability standard providing examples of this language applied to a small DP.

2) R3 through R7 add specificity and scope to the NERC PRC-006-1 standard requirements pertaining to identification and mitigation of islands as noted below.   


a. The Planning Coordinator needs to include additional items in their island identification criteria (R3).


b. The Planning Coordinator shall supply their island identification criteria (R4) and respond (R5) to any comments received on the island identification criteria from affected entities.


c. The Planning Coordinator shall identify and document islands by: applying the island identification criteria at least every 60 months (R6), supplying the results of applying the island identification criteria to affected entities (R6, Part 6.1), inviting, in writing, the participation of applicable entities, in the establishment of the mitigation plan (R6, Part 6.2) and establishing a mitigation plan to balance generation and Load and restore frequency in each area of islanding should the area of islanding become separated from the interconnection (R6, Part 6.3).


d. .Affected Distribution Providers, Transmission Owners and Generator Owners shall implement their portion of any mitigation plan (for the island(s)) as determined by the Planning Coordinator (R7).


Do you agree with the added specificity and scope pertaining to how islands are identified and addressed?

Abstain

2) If not, please provide specific suggestions.

 

3) R8 and R9 extend the scope of the NERC PRC-006-1 standard to apply to Generator Owners’ underfrequency trip characteristics in planning UFLS programs as noted below. 

  
a. The premature tripping of a generating unit may have a very negative effect on the Bulk Electric System during a frequency excursion, and thus it is important to include a Generator Owner requirement within a standard dealing with UFLS. Generator Owners are required to either: 1) Set underfrequency protection in accordance with PRC-006-RFC-01 Attachment 1 (Time vs. Frequency curve) for generators that have automatic underfrequency protection installed, 2) establish and follow procedures for underfrequency operation in accordance with PRC-006-RFC-01 Attachment 1, for generators that do not have automatic underfrequency protection installed, or 3) arrange for Load shedding to be installed by mutual agreement with Distribution Providers, in addition to that required by the Planning Coordinator in Requirement R1 or Requirement R2, for generators that cannot meet the specifications in PRC-006-RFC-01 Attachment 1. (R8) (Note: the Time vs. Frequency curve in Attachment 1 is consistent with the curves in the NERC PRC-006-1 and draft PRC-024-1 standards (R11)).


b. Generator Owners (which are required to comply with R8) are required to supply underfrequency trip setting data to populate the Planning Coordinator’s UFLS data base (R9).  It is important for the Planning Coordinators to have such generator data in order to perform an accurate UFLS assessment (R10).  (This requirement may be removed once the NERC PRC-024-1 standard is completed and approved.)


Do you agree with the extended scope to include Generator Owners?

No

3) If not, please provide specific suggestions.

IMEA supports comments submitted by Indiana Municipal Power Agency.

4) R10 and R11 extend the scope of NERC PRC-006-1 standard by including requirements to assess UFLS program implementation (in addition to UFLS program design required in the NERC PRC-006-1 standard) as noted below. 

  
a. The Planning Coordinator is to perform, document and make available an assessment of the effectiveness of the “implementation” of the UFLS programs.  The NERC PRC-006-1 standard only requires an assessment of the “design” of the UFLS programs.  This assessment will assess the effectiveness of the implemented UFLS programs using the information contained in the Planning Coordinator’s database which, while satisfying the design requirements, may exceed the design specifications (R10).


b. Applicable Distribution Providers, Transmission Owners and Generator Owners are to complete any required changes to the implementation of the UFLS program based on any implementation deficiencies noted in the Planning Coordinator’s assessment.  The NERC PRC-006-1 standard only requires the applicable entities to provide automatic tripping of Load in accordance with the UFLS program design and does not account for any changes which may be found necessary based on the Planning Coordinator’s assessment of implementation.  Such changes may be necessary for the overall effectiveness of the UFLS program when arresting frequency excursions.  The three calendar year completion interval was chosen to give applicable entities a reasonable amount of time for making changes in the field (R11).


Do you agree with the need to assess UFLS program implementation as well as design?

Abstain

4) If not, please provide specific suggestions.

 

5) The Standard Drafting Team believes the standard is ready for Category Ballot. Do you agree?

No

5) If not, please provide specific suggestions that would make it acceptable to you.

Please see comments under 1 and 3.

Created at 9/7/2012 10:09 AM by System Account
Last modified at 9/7/2012 10:09 AM by System Account