NOTICE DATE:  March 14, 2012

NOTICE TYPE:  W-A031413-01 Operations

SHORT DESCRIPTION:  Update to the West to North Generic transmission interface

INTENDED AUDIENCE:  ERCOT Market Participants

DAY AFFECTED:  March 20, 2013

LONG DESCRIPTION:  Beginning March 20, 2013, two new transmission lines associated with the West to North Stability Limit are expected to be energized. This adds in the new CREZ lines indicated on the PUCT tracking website "West Shackelford to Navarro/Sam Switch Line<http://www.texascrezprojects.com/page113731122.aspx>". Energizing this new set of lines is anticipated to increase the West to North transfer limit.

Energization of these new transmission lines will impact the value of the West to North Stability Limit utilized in the Day-Ahead Market, as well as the value calculated in the real-time Transient and Voltage Security Assessment Tools (TSAT and VSAT respectively), starting on Operating Day March 20, 2013.

ERCOT will also be implementing the new planning matrix (see attachment). Note that this Matrix is used for conditions when no thermal generators are in service and ERCOT uses TSAT and VSAT to calculate West to North Stability limits for conditions when thermal generation is in service. The interface definition for the West to North Stability Limit was modified to include these new transmission lines with the Network Operations Model, in preparation for these new lines coming into service with the understanding and expectation that the limit value would not be affected until these lines were energized.

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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