4/15/2018 1:11 0.095 59.909 0:11:54 No PMU Report Created 349 29,628 18% 180,352 4/18/2018 10:20 0.097 59.914 0:07:34 No PMU Report Created 460 38,487 33% 225,994 4/21/2018 17:11 0.249 59.719* 0:03:38 0.81 12% 1250 36,486 32% 190,214 0.75 13% 4/28/2018 9:50 0.069 59.904 0:00:59 No PMU Report Created 299 34,434 13% 216,030 4/28/2018 18:15 0.103 59.910 0:09:23 No PMU Report Created 408 43,739 15% 234,444 *This is the lowest frequency seen by ERCOT EMS. High speed data recorders shows frequency went as low as 59.709Hz. (Note: All data on this graph encompasses frequency event analysis based on BAL-001-TRE-1.) Responsive Reserve Events There were three events where Responsive Reserve MWs were released to SCED in April. The events highlighted in blue were related to frequency events reported in Section 2.1 above. Date and Time Released to SCED Date and Time Recalled Duration of Event Maximum MWs Released Comments 4/15/2018 1:11 4/15/2018 1:14 0:02:44 308 4/21/2018 17:11 4/21/2018 17:15 0:03:40 1548 Of the 1548MW of RRS requested, 1298MW came from PFR while the remainder was expected from Load Resources. 546.5MW of Load Resources tripped offline to provide their RRS obligation. 4/28/2018 9:50 4/28/2018 9:51 0:00:56 287 Load Resource Events Date and Time Released Date and Time Recalled Duration of Event Maximum MW Comments 4/21/2018 17:11 4/21/2018 17:30 0:19:00 546.5 At approximately 17:11 on 04/21/2018, 1,250 MW of
Congestion Analysis The total number of congestion events experienced by the ERCOT system decreased in April. There were 38 instances over 26 days on the Generic Transmission Constraints (GTCs) in April. Notable Constraints Nodal protocol section 3.20 specifies that ERCOT shall identify transmission constraints that are active or binding three or more times within a calendar month. As part of this process, ERCOT reports congestion that meets this criterion to ROS. In addition ERCOT also highlights notable constraints that have an estimated congestion rent exceeding $1,000,000 for a calendar month. These constraints are detailed in the table below. Rows highlighted in blue indicate the congestion was affected by one or more outages. For a list of all constraints activated in SCED for the month of April, please see Appendix A at the end of this report. Contingency Name Overloaded Element # of Days Constraint Active Congestion Rent Transmission Project CRLNW-LWSSW 345kV Carrollton Northwest - Lakepointe Tnp 138kV 23 $27,871,275 Oncor_NW Carrollton - LakePointe (5488) Basecase PNHNDL GTC 25 $14,267,102 LP&L Option 4ow & Panhandle Loop (5180, 5208) Jones Street Tnp to Lewisvil Ti Tnp - West Tnp 138kV 13 $11,808,730 Elmcreek-Sanmigl 345kV Pawnee Switching Station - Calaveras 345kV 6 $4,568,451 Wink Sub to YUCCA DRIVE SWITCH LIN Andrews County South - Amoco Three Bar Tap 138kV 10 $4,289,903 Jewet-Sng 345kV Btu_Jack_Creek - Twin Oak Switch 345kV 11 $3,467,023 Houston Import Project (4458) CAGNON to KENDALL LIN 1 Cico - Comfort 138kV 21 $3,187,828 Basecase Omega - Horse Hollow Generation Tie 345kV 18 $3,087,990 Vensw-Evrsw 345kV Oakhill Tap 2 - Tate Tap East 138kV 3 $2,910,643 Re Roserock Solar Plant to L Yucca Drive Switch - Gas Pad 138kV 14 $2,891,761 Yucca Junction (4549)
East Harrison to La Palma 69 Haine Drive - La Palma 138kV 471 $5,189,980 Wink Sub to YUCCA DRIVE SWITCH LIN Winkler County 6 Tnp - Wickett Tnp 69kV 1,127 $4,538,878 Far West Texas Project Basecase Omega - Horse Hollow Generation Tie 345kV 5,261 $4,304,033 CAGNON to KENDALL LIN 1 Cico - Comfort 138kV 3,966 $4,187,668 KLEBERG AEP to LOYOLA SUB LIN 1 Loyola Sub 138/69kV 4,630 $3,777,770 AEP_Angstrom (15TPIT0069) System Events ERCOT Peak Load The unofficial ERCOT peak load for the month was 47,885 MW and occurred on April 24th, during hour ending 18:00. Load Shed Events None. Stability Events None. Notable PMU Events None. DC Tie Curtailment Date DC Tie Curtailing Period # of Tags Curtailed Initiating Event Curtailment Reason 4/12//2018 Eagle Pass HE 0700 2 Forced Transmission Outage in the area DC Tie Forced Outage 4/23/2018 Railroad HE 1000 - 1300 & HE 2400 3 DC Tie de-rated to 150MW DC Tie de-rated to 150MW TRE/DOE Reportable Events ONCOR submitted an EOP-004 report on April 10, 2018 Reportable Event Type: Physical Threat and Damage or Destruction to a Facility. ERCOT ISO submitted an EOP-004 report on April 21, 2018 Reportable Event Type: Generation Loss Kiowa submitted an EOP-004 report on April 21, 2018 Reportable Event Type: Transmission Loss New/Updated Constraint Management Plans None. New/Modified/Removed RAS None.