NOTICE DATE: December 28, 2022
NOTICE TYPE: W-A122822-01
SHORT DESCRIPTION: Implementation/Change of maximum shadow price for an irresolvable constraint in SCED
INTENDED AUDIENCE: All Market Participants
DAY AFFECTED: December 28, 2022
LONG DESCRIPTION: On December 24, 2022, two constraints were determined to be irresolvable per the criteria ERCOT Section 3.6.1 of the Other Binding Document (OBD), Methodology for Setting Maximum Shadow Prices for Network and Power Balance Constraints. In particular, due to the existing irresolvable constraint SBEVASH8: HAMILT_MAVERI1_1 sharing the same constraint element as SBE2ASH8: HAMILT_MAVERI1_1, a corresponding update to its maximum Shadow Price is also being made. The updates to the maximum Shadow Prices will occur between 5:00 PM and 6:00 PM Central Prevailing Time (CPT) on December 28, 2022 and be effective on December 28, 2022. The contingency/constraint pairs and updated maximum Shadow Prices are as follows:
| Contingency Name |
Constraint Name |
From Station/kV |
Description |
Maximum Shadow Price |
| MCOMPR28 |
RYSSW_FMR2 |
RYSSW/138 |
Loss of the 138 kV lines from COMMERCE SWITCH and CROSSROADS SWITCH to PARIS SWITCH overloads the 138/69 kV transformer at ROYSE |
3,500 $/MWh |
| SBEVASH8 |
HAMILT_MAVERI1_1 |
HAMILTON/138 |
Loss of the 138 kV line from ASHERTON to MCLEAN SOLAR overloads the 138 kV line from HAMILTON ROAD to MAVERICK |
3,500 $/MWh |
| SBE2ASH8 |
HAMILT_MAVERI1_1 |
HAMILTON/138 |
Loss of the 138 kV line from BEVO to ASHERTON overloads the 138 kV line from HAMILTON ROAD to MAVERICK |
3,500 $/MWh |
These new maximum Shadow Prices will be used for all constraints in Security-Constrained Economic Dispatch (SCED), which share the same monitored elements (i.e. constraint name) and directions.
ADDITIONAL INFORMATION: The ERCOT business practice document, Setting the Shadow Price Caps and Power Balance Penalties in Security Constrained Economic Dispatch, can be found in the Methodology for Setting Maximum Shadow Prices for Network and Power Balance Constraints under Key Documents on the Real-Time Market webpage, and under the Other Binding Documents List, both of which are on the ERCOT website.
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