NOTICE DATE:  December 9, 2010
NOTICE TYPE:  M-A120910-01 NPRR
SHORT DESCRIPTION:  Implementation Details of NPRR277
INTENDED AUDIENCE:  ERCOT Market Participants
DAY AFFECTED:  December 1, 2010
LONG DESCRIPTION:  Nodal Protocol Revision Request (NPRR) 277, as approved by the ERCOT Board of Directors, became effective for Operating Day December 1, 2010. NPRR277 added a new parameter (REGP) to the SCED up ramp rate (SURAMP) calculation.
The system was originally coded as SURAMP = Ramp Rate - (Regulation/X), where X = 5. According to the system requirements, X must be an integer. The new formula is:
SURAMP = Ramp Rate - (Regulation * REGP/5).
In order to accomplish the change without adding a new parameter to the existing code, the original X is replaced with 5/REGP and the equation is re-written as:
SURAMP = Ramp Rate - (Regulation / (5/REGP)).
REGP is the percentage of regulation service for which ramp rate will be reserved in real-time. The value is to be between zero and one with an initial setting of 0.75 as agreed upon through the stakeholder process. Due to the ERCOT System requiring the 5/REGP parameter to be an integer, ERCOT will be required to round the calculation of 5/0.75 from 6.66 to 7 which results in the REGP value effectively changing to 0.714 ( 5/0.714 = 7).
ERCOT changed the REGP value to 0.714 at 23:59 CST November 30, 2010, to be effective starting with Operating Day December 1, 2010.
CONTACT:  If you have any questions, please contact your ERCOT Account Manager. You may also call the general ERCOT Client Services phone number at (512) 248-3900 or contact ERCOT Client Services via email at [log in to unmask]<mailto:[log in to unmask]>.
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