1. PRC-006-RFC-01 Automatic Under Frequency Load Shedding Requirements
RFC Webinar
June 17, 2009
Presented By: Mark Kuras
Chair, UFLS SDT

2. Automatic Under Frequency Load Shedding Requirements
Standards Committee approved SAR on February 24th, 2006
RFC standard was created to meet the requirements of the present NERC PRC-006 standard
Proposed standard lists requirements for:
UFLS Program implementation (R1)
Creation of a Credible Island determination methodology (R2)
Assessment of credible islands (R3)
Generator under frequency protection (R4)
Creation of UFLS Database (R5)
Population of the UFLS Database (R6)
UFLS Program effectiveness evaluation (R7)
Information exchange (coordination) (R8)

3. Posted for 5 comment periods
Automatic Under Frequency Load Shedding RequirementsabilityCommenting and Posting
Posted for 5 comment periods
5/16/07 thru 6/14/07 – 20 commenters
10/29/07 thru 11/28/07 – 21 commenters
5/1/08 thru 5/30/08 – 24 commenters
9/5/08 thru 10/6/08 – 23 commenters
1/21/09 thru 2/19/09 – 21 commenters

4. Issues and Concerns Expressed by Commenters
During the last rounds of commenting, only seven general issues came up

5. Issues and SDT View Issue
Applicability goes beyond the NERC Compliance Registry Criteria
SDT View
Distinguishing between BES and non-BES is not a factor in the reliability impact of lost generation during an under-frequency condition
The material impact to reliability is solely a function of the physics of electricity
Loss of generation from a 69 kV station has precisely the same effect on BES frequency as loss of the same amount of generation from a BES station

6. Issues and SDT View
The NERC Compliance Registry Criteria is subject to considerations other than reliability and so a conflict has arisen between reliability and other considerations
The SDT has compromised on the applicability from previous drafts of the standard, but believes that reliability would be poorly served if further compromises were made in deference to these other considerations
Also Note 4 of the Compliance Registry Criteria states
4. If an entity is part of a class of entities excluded based on the criteria above as individually being unlikely to have a material impact on the reliability of the bulk power system, but that in aggregate have been demonstrated to have such an impact it may be registered for applicable standards and requirements irrespective of other considerations.

7. Issues and SDT View Issue
LSE no longer exists in the Standard, but Distribution Provider should be removed too
SDT View
Distribution Provider is a valid NERC Functional Model entity that is presently required to be registered, even though they are not part of the BES
The NERC Functional Model indicates that Distribution Providers are responsible for UFLS implementation, not Transmission Owners

8. Issues and SDT View Issue Small Distribution Providers SDT View
Compliance problems lie in the number of feeders available to balance steps equally
Can group together
Exemption criteria included
Complete exclusion would unfairly burden other Distribution Providers

9. Issues and SDT View Issue Generator Protection SDT View
Establishes minimum clearing times
Having no protection makes you compliant
Very common
Operators must realize that they should not trip units faster then the standard minimums

10. Issues and SDT View Issue
My generator cannot meet the standard’s minimum clearing requirements
SDT View
Time periods based on major manufacturer protection requirements
Also based on legacy Regional requirements
Historically very little exposure to these frequencies

11. Issues and SDT View Issue Effective Dates SDT View
Standard will apply to applicable RFC Members on RFC Board approval
Standard will apply to applicable RFC Registered Entities on FERC approval
The same for all regional standards

12. Issues and SDT View Issue
Stop RFC’s UFLS standard development and wait for NERC
SDT View
This standard is to meet the requirements of the presently in place NERC standard
This standard will apply in the interim until NERC approves PRC
NERC standard is still a ways away

13. Our Goal
RELIABILITY
Questions?
FIRST