Electric Energy, Inc. (EEI), Docket No. RC13-1 (October 31, 2012)
Reliability Standard: BAL-002-0
Requirement: 4
Region: SERC
Issue: EEI, in its role as a BA, submitted a self-report in June 2011 stating that it had a Reportable Disturbance in the form of a unit trip that resulted in a drop in the Area Control Error (ACE) greater than 80% of the most severe single contingency. After that event, EEI did not return ACE to zero within 15 minutes as required by BAL-002-0 R4.2. Further, on June 5, 2011, EEI's Unit 3 tripped offline, resulting in a drop in the ACE greater than 80% of EEI's largest single contingency. EEI's largest single contingency is 167 MW. At the time of the event, Unit 3 was at 170 MW (158 MW net) and ACE was at +3 MW. ACE dropped to -163 MW immediately following the trip. The EEI systems operator contacted MISO to schedule a 170 MW coordinated adjustment to the interchange schedule. However, the systems supervisor was slow in entering the 10-minute ramped adjustment in supervisory control and data acquisition (SCADA) which caused EEI to exceed the 15 minute limit to restore ACE. EEI returned ACE to zero within 17 minutes of the start of the Reportable Disturbance.
Finding: SERC determined that the issue posed a minimal risk to BPS reliability because EEI was two minutes late in returning ACE to zero after the start of the Reportable Disturbance; and MISO had sufficient reserves to cover the Disturbance Control Standard event. This is a repeat violation for EEI, but the previous violation occurred nearly three years earlier, and so this violation was deemed appropriate for FFT treatment.
El Paso Electric Company (EPE), Docket No. RC13-6-000 (February 28, 2013)
Reliability Standard: BAL-002-0
Requirement: 4
Region: WECC
Issue: While conducting a compliance audit of EPE, WECC found an issue with EPE's Disturbance Control Performance. EPE, in its role as a BA, had not activated the contingency reserves of the Southwest Reserve Sharing Group while a reportable disturbance was ongoing. EPE was responsible for disturbance recovery during the event; however, EPE did not recover its Area Control Error (ACE) until 22 minutes after the issuance of the disturbance. The Disturbance Recovery Period to return the ACE to zero is 15 minutes, but EPE did not recover its ACE until seven minutes after the 15-minute time window.
Finding: The issue was deemed to pose minimal risk to BPS reliability and not serious or substantial risk. The risk to BPS operations was mitigated because it was an isolated case of EPE recovering its ACE seven minutes late; however, the result was that EPE's Disturbance Control Standard for Q2 2010 was less than 100%. The event caused EPE to lose only 101 MW of generating capability over the seven-minute period. Also, no overload occurred during the relevant period nor were any voltage issues experienced on the tie lines.
