NOTICE DATE: October 7, 2011

NOTICE TYPE: M-C100711-01 SCR

SHORT DESCRIPTION: Implementation details of SCR760 – Phase 1

INTENDED AUDIENCE: Transmission Services Providers

DAY AFFECTED: October 17, 2011

LONG DESCRIPTION: System Change Request (SCR) 760, Recommended Changes Needed for Information Model Manager and Topology Processor for Planning Models, was approved by the ERCOT Board on March 22, 2011. SCR760 provides for the implementation and support of nine system changes that update the Network Model Management System (NMMS) Database, and/or the tools used to create the Annual Planning Model, to support additional features required by the Transmission Service Provider Planning teams in an effort to more efficiently and accurately build the Annual Planning Models.

ERCOT plans to implement the SCR760 functionality in three phases, with phase 1 of the implementation to be effective on October 17, 2011. Phase 1 will include SCR760 enhancements 3, 7 and 8, as described below:

Enhancement 3: Allow the representation of ratings on breakers and switches in IMM that are converted to zero impedance lines by the Topology Processor for use in PSS/E cases. IMM already has rating attributes associated with breakers and switches. ERCOT will remove validation rules to make these rating attributes available to the TSP NOMCR process and will modify the topology processor to transfer these ratings into the Model on Demand process as zero impedance elements with a rating.

Enhancement 7: Allow any valid PSS/E IDs assigned in IMM to be output by Topology Processor. Current SSWG cases allow zero impedance branches to have any valid two-character PSS/E ID. This change would alter the logic of Topology Processor and allow SSWG member assigned circuit IDs to be output by Topology Processor. This enhancement also removes validation rules that limited the PSS/E ID on series devices to Sx.

Enhancement 8: Allow representation of a phase shift for an autotransformer winding in the Topology Processor PSS/E cases. Topology Processor should check the value in the “Connection Type” attribute between TransformerWinding objects. If two windings are U-D, then process as a 30 degree phase shift.

ADDITIONAL INFORMATION: SCR760 and associated documents can be found on the ERCOT website, under Market Rules, at http://www.ercot.com/mktrules/issues/scr/750-774/760/index.

Further notices will be sent with details on phases 2 and 3 of the implementation.

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].

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.