NOTICE DATE: September 8, 2015 NOTICE TYPE: W-A090815-01 Operations SHORT DESCRIPTION: New Laredo Generic Transmission Constraint INTENDED AUDIENCE: ERCOT Market Participants DAY AFFECTED: September 9, 2015 LONG DESCRIPTION: ERCOT is implementing a new Generic Transmission Constraint (GTC) for the Laredo region. This GTC has been created to address voltage stability concerns that occur under certain system conditions when there is a strong import into the Laredo area. The Laredo GTC is an interface constraint which includes the following transmission lines: San Miguel - Lobo 345 kV Holcomb - North Laredo Switch 138 kV Piloncillo - North Laredo Switch 138 kV La Quinta - Lobo 138 kV Rio Bravo - Molina 138 kV Freer - Lobo 69 kV The Generic Transmission Limit (GTL) associated with this GTC will be calculated based on the sum of the flows on these lines which feed into the Laredo area. This GTC will be effective as of September 9, 2015, and details associated with this GTC can be found on the ERCOT MIS Secure Area in the "Generic Transmission Constraints" portlet. A Digital Certificate is required to access the MIS. CONTACT: If you have any questions or comments pursuant to Protocol Section 3.10.7.6 (3) on this GTC, 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]>. If you are receiving email from an ERCOT distribution list that you no longer wish to receive, please follow this link in order to unsubscribe from this list: http://lists.ercot.com. sa