Title: Generation Resource Start-Up and Shut-Down process
Next Group:
Next Step:
Status: Approved on 09/20/2011
Effective Dates:


Date Gov Body Action Taken Next Steps
09/20/2011 BOARD Approved
08/04/2011 TAC Recommended for Approval Board consideration
07/21/2011 PRS Recommended for Approval TAC consideration
07/07/2011 TAC Remanded PRS consideration
06/23/2011 PRS Recommended for Approval TAC consideration
05/19/2011 PRS Recommended for Approval PRS consider the IA and CBA
04/21/2011 PRS Deferred/Tabled PRS consideration

Voting Record

Date Gov Body Motion Result
09/20/2011 BOARD To approve NPRR348 as recommended by TAC in the 8/4/11 TAC Report. Passed
08/04/2011 TAC To recommend approval of NPRR348 as recommended by PRS in the 7/21/11 PRS Report Passed
07/21/2011 PRS To recommend approval of NPRR348 as amended by the 7/20/11 Luminant Energy comments and as revised by PRS. Passed
07/07/2011 TAC To remand NPRR348 to PRS. All Market Segments were present for the vote Passed
06/23/2011 PRS To endorse and forward the 5/19/11 PRS Report, Impact Analysis, and Cost Benefit Analysis for NPRR348 to TAC with a recommended priority of Critical and rank of 8.4. Passed
05/19/2011 PRS To recommend approval of NPRR348 as submitted. Passed
04/21/2011 PRS To table NPRR348 for one month. Passed

Vote tallies here reflect individual votes, not the weight of the votes by market segment. Affirmative votes are not recorded in these vote tallies. For additional details on the voting record, please consult the Recommendation or Action Report, or the official vote tally if available, as posted in the key documents.


Status: Approved
Date Posted: Apr 6, 2011
Sponsor: ERCOT
Urgent: No
Sections: 3.9.1,, 6.4.3,,, 6.6.5,
Description: As part of this Nodal Protocol Revision Request (NPRR), Protocol language concerning the use of the "ONTEST" Resource Status during Start-Up and Shut-Down has been removed. Language has been added to address the Start-Up and Shut-Down processes. For Start-Up, language is added so that Resources are exempt from Base-Point Deviation Charges and Generation Resource Energy Deployment Performance (GREDP) metrics when the Resources average base-point value is below the average telemetered Low Sustainable Limit (LSL). The expectation is that when a Resource is receiving base-points below its LSL, the Resource is starting up/shutting down and not necessarily responding to Security Constrained Economic Dispatch (SCED) instructions. For Shut-Down, a new Resource Status is created called "SHUTDOWN". This status will be used by the Resource Limit Calculator (RLC) to calculate dispatch limits for SCED which ramp a Resource down to 0 MW according to the Resource’s provided ramp rate. Again, a Resource will be exempt from Base-Point Deviation Charges and GREDP metrics when the Resource’s average base-point is below the average telemetered LSL.
Reason: Under the current Nodal Protocols, a Resource Status of "ONTEST" is telemetered for Resources that are either starting up or shutting down. This potentially causes two problems for the ERCOT system and the ERCOT Operators. The first problem can occur when a Qualified Scheduling Entity (QSE) telemeters a Resource Status of "ONTEST" and SCED sends a Base Point to that Resource equal to its current telemetered output. This results in ERCOT deploying Regulation to account for any movement by that Resource between SCED executions. There have been periods when a number of Resources have started up or shut down quickly and simultaneously. This can cause frequency issues and may result in ERCOT manually executing SCED and deploying additional Ancillary Services. These concerns will be greatly reduced if Resources are required to follow SCED instructions when they are receiving base-points at or above their LSL. A new "SHUTDOWN" Resource Status will force SCED to Dispatch a Resource down to 0 MW according to its ramp rate. This will ensure that when a Resource is intending to shutdown, SCED will only be ramping the Resource down and not changing ramp direction. This logic will provide ERCOT visibility to where the Resource is planned to go in the next five minutes and will provide a method for a Resource to come off-line as required even if it is operating above its LSL. The second problem is that ERCOT Operators are not currently able to distinguish easily between periods when Generation Resources are performing testing and when they are starting up/shutting down. Discontinuing the use of "ONTEST" during start-up/shut-down will address this concern.

Key Documents

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