NOTICE DATE:  July 1, 2008

NOTICE TYPE:  W-A070108-01   Operations

CLASSIFICATION: Public

SHORT DESCRIPTION:  ERCOT will implement the addition of two CREs on Operating Day July 3, 2008.

INTENDED AUDIENCE:  QSEs

DAY AFFECTED:  July 3, 2008

LONG DESCRIPTION:  Protocol Section 7.2.3, Determining Closely Related Elements (CREs), provides that ERCOT staff may propose modifications to the list of CREs and shall present modifications to TAC for approval; if TAC takes no action within seven days, the proposed modification shall be deemed approved. 

On June 26, 2008, ERCOT proposed modifications to the list of CREs to TAC.  TAC took no action on the proposed CRE modifications; therefore, ERCOT will implement the addition of two CREs consisting of a combination of several lines for system stability purposes as of Operating Day July 3, 2008:

1.      West – North Transfer Stability Limit consisting of the sum of flows on the following six lines:

LONG CREEK SWITCHING STATION – GRAHAM SES (345kV, double circuit)

TONKAWA SWITCH – GRAHAM SES (345kV)

BOWMAN SWITCH – GRAHAM SES (345kV)

BOWMAN SWITCH – JACKSBORO SWITCHING (345kV)

SAN ANGELO CREEK – COMANCHE SWITCH TU (345kV)

2.      Houston Voltage Stability Limit consisting of the sum of flows on the following four lines from North – Houston:

JEWETT to TH WHARTON (345kV)

JEWETT to TOMBALL (345kV)

GIBBONS CREEK to O’BRIEN (345kV)

ROANS PRAIRIE to KUYKENDAHL (345kV)

When either of these are binding elements, ERCOT will do the following:

• Manually set the West-North or North-Houston CSC limit displayed on http://mospublic.ercot.com/ercot/jsp/csc_cre.jsp
• Post a message to the MIS at http://oldercot.ercot.com/ercotPublicWeb/Message/MessageSearch.asp indicating the OC1 operating condition is due to a stability limit

ADDITIONAL INFORMATION:  The ERCOT proposal to TAC for the CRE modifications is posted as Agenda Item 9 on the June 26 TAC meeting page at http://www.ercot.com/calendar/2008/06/20080626-TAC.

ERCOT will post additional details of the stability study results used to establish these limits to the secure Planning and Operations Information website at http://planning.ercot.com/login/login.  This website is scheduled to be activated on July 7, 2008.

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 e-mail at [log in to unmask].

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