NOTICE DATE:  July 14, 2016
NOTICE TYPE:  W-A070816-05 Unplanned Outage
SHORT DESCRIPTION:  Initial root cause assessment of Energy Management System (EMS) failure on July 7, 2016

INTENDED AUDIENCE:  ERCOT Market Participants
DAY AFFECTED:  July 7, 2016 and Settlement of July 7, 2016

LONG DESCRIPTION:  As previously indicated in Market Notice W-A070816-01 issued on July 8, 2016, ERCOT experienced an issue with the Energy Management System (EMS) on Thursday, July 07, 2016 from 11:42 am until 12:05 pm Central Prevailing Time (CPT).  ERCOT's initial root cause assessment has determined that the EMS failure was triggered by an ERCOT employee incorrectly executing a command in production that corrupted data in the network model in the EMS.  Subsequently, the corrupt data was passed through into downstream systems including the Market Management System (MMS), Settlements, and reports.  ERCOT corrected and verified the data by 1:23 pm CPT, at which time EMS operations returned to normal.

The impact of the corrupt data was on core systems including EMS, MMS and Settlements which put out inaccurate data and reports.  Pricing for the affected duration are corrected in accordance with the ERCOT Protocols and consistent with Market Notice W-A070816-01.  ERCOT systems beyond pricing have been impacted.  For example, Emergency Base Point data and generation net telemetry data (GSSPLITSCA) were corrupted for the July 7, 2016 Operating Day.

ERCOT is still determining overall impacts to data integrity issues that occurred as a result of this EMS failure and will communicate any additional progress with Settlement and/or other data restoration efforts over the course of the coming weeks with additional Market Notices.   ERCOT further plans to add this issue to the agenda of the July 28, 2016 Technical Advisory Committee (TAC) meeting and update TAC with the latest information.
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]<mailto:[log in to unmask]>.
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