NOTICE DATE: April 16, 2010

NOTICE TYPE: M-A041610-01 Operations

SHORT DESCRIPTION: Proposal to Disable Sandow Switching Station SPS #40 and #43

INTENDED AUDIENCE: ERCOT Market Participants

DAY AFFECTED: June 1, 2010

LONG DESCRIPTION: ERCOT has received a request to disable the Special Protection System (SPS) at the Oncor Sandow Switching Station (Oncor SPS #40 and #43). SPS #40 protects against overloads on the Sandow – Minerva 138 kV line. SPS #43 protects against overloads on Sandow – Taylor, Sandow – Elgin and Elgin – Gilleland 138 kV lines. Oncor believes that all transmission upgrades necessary to exit these SPSs will be completed by the end of May.

The request to disable these SPSs is being reviewed by ERCOT, as described in the SPS Approval Procedure. Comments on the proposed SPS disabling are due by April 29, 2010, and should be submitted to [log in to unmask] using the attached comment form. Any questions or concerns raised during this timeframe will be addressed by ERCOT staff or the entity submitting the SPS proposal.

Further details on these SPSs can be found in the “Special Protection Systems Information” section of the ERCOT Planning and Operations Information secure website: http://planning.ercot.com/login/login.

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].

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