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

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)

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

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

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

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.

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

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

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

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

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

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-006-01 NERC standard is still a ways away

Our Goal RELIABILITY Questions? FIRST