NOTICE DATE: July 12, 2016

NOTICE TYPE: W-A071216-01 Operations

SHORT DESCRIPTION: Proposal to Modify Permian Basin Special Protection System

INTENDED AUDIENCE: ERCOT Market Participants

DAY AFFECTED: Comments due July 21, 2016

LONG DESCRIPTION: ERCOT has received a proposal from Oncor Electric Delivery Company LLC (Oncor) to modify the Special Protection System (SPS) at Permian Basin Switching Station (Permian Basin). The Permian Basin SPS is designed to monitor and relieve thermal violations on the Permian Basin – Wink 138 kV line (6550) and the Permian Basin – Ward Gulf Tap – Wink 138 kV line (6545_A).

Oncor has completed the upgrade of the Permian Basin – Wink 138 kV line, increasing the static emergency rating from 186 MVA to 394 MVA. The upgrade of Permian Basin – Ward Gulf Tap – Wink 138 kV line will be implemented in sections, and will be completed in summer 2017. Until the upgrade is completed, the static emergency rating of the Permian Basin – Ward Gulf 138 kV line will increase from 249 MVA to 287 MVA. Oncor is proposing to modify the pickup settings for the relays monitoring the Permian Basin – Ward Gulf Tap – Wink 138 kV line and to disable the relays monitoring the Permian Basin – Wink 138 kV line.

The proposal to modify the Permian Basin SPS is being reviewed by ERCOT. Comments on the proposal are due by July 21, 2016 and should be submitted to [log in to unmask] using the attached comment form. Any questions or concerns submitted by this date will be addressed by ERCOT or Oncor.

ACTION REQUIRED: Any comments to this proposal are due to ERCOT by July 21, 2016 using the attached form.

ADDITIONAL INFORMATION: Information regarding all SPSs can be found in the “Special Protection Systems and Remedial Action Plans” portlet located on the Long-Term Planning page of ERCOT’s Market Information System (MIS). A Digital certificate is required to access the MIS.

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].