Operations

Tue, Jan 26, 2021 04:18 PM

M-A012621-01 Planned Transmission Outage Restrictions for Summer


NOTICE DATE: January 26, 2021

NOTICE TYPE: M-A012621-01 Operations

SHORT DESCRIPTION: Planned Transmission Outage Restrictions for Summer

INTENDED AUDIENCE: ERCOT Market Participants

DAYS AFFECTED: May 15 through September 15

LONG DESCRIPTION: In an effort to manage Planned Transmission Outages that might limit generation availability during high Load conditions, ERCOT is implementing a revised set of restrictions on Planned Transmission Outages, which will be in place each summer going forward, unless subsequently modified due to changed conditions.   ERCOT will apply these summer Planned Outage restrictions, in addition to normal outage coordination guidelines, in its standard processes for evaluating Planned Transmission Outages.

These restrictions apply to Planned Outages in effect from May 15 through September 15 (the summer restriction window).  For Planned Outages that begin before May 15 or extend after September 15, the restrictions apply to the duration of the Planned Outage that extends into the summer restriction window.  The restrictions apply to Planned Outages of existing equipment; they do not apply to Planned Outages of new facilities when those Outages are necessary to synchronize the future equipment in the Network Operations Model with the actual initial energization date of the new facilities (Protocols Section 3.3.1, ERCOT Approval of New or Relocated Facilities).

General Restrictions for Summer Planned Outages:

345kV

  • No Outages during Hour Ending (HE) 1300 through HE 2000.
  • No 345kV bus Outages that alter system topology (pre- or post-contingency).  Outages on double breaker or breaker-and-a-half buses may be allowed with a 4-hour restoration.  Transmission Service Providers (TSPs) are required to ensure proper interim contingency definitions are included in the Network Operations Model prior to the Outage occurring so that ERCOT systems can properly assess system conditions during the bus Outage.

138kV

  • No Outages during HE 1300 through HE 2000 if the Outage may affect generation dispatch.
  • No continuous 138 kV Outages longer than 7 days
  • No continuous 138 kV Outages with a restoration time greater than 6 hours.

69kV

  • No Outages during HE 1300 through HE 2000 if the Outage would affect generation dispatch.

Some exceptions to the general restrictions for summer Planned Outages listed above MAY BE allowed, on a case by case basis, as listed in the potential exceptions below, or as otherwise determined by ERCOT.  In order for a Planned Outage to be considered under a potential exception, the TSP requesting the Outage should provide the information necessary for ERCOT to consider the applicability of the potential exception at the time the Planned Outage is submitted by including the exception request and justification in the Comment field for that Outage in the Outage Scheduler.

Potential Exceptions may include:

  • Outages on radial transmission that does not connect available generation.
  • Outages on local load-serving networks that are essentially radial in nature and do not contain available generation.
  • Daily full-day Outages on specific Competitive Renewable Energy Zone (CREZ) transmission lines under low wind conditions.
  • Outages which pose a greater transmission system reliability risk through the summer if NOT completed.
  • Outages where the Outage itself would reduce congestion.
  • Outages where the reliability need for the Outage, including the interconnection of new generating capacity, exceeds the potential risk that the Outage will restrict generation.

In the event of a second occurrence of an applicable Planned Outage being unavoidably extended beyond HE 1300 for a particular TSP, the approval of any of that TSP’s subsequent Planned Outages that have not already begun will be withdrawn, and future Outages will not be approved, unless the Outage has a 4 hour or less restoration time.

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 ClientServices@ercot.com.

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dg/mm