Rayburn Electric Cooperative (REC) submitted the Rand Area Loop project for RPG review in May 2024, a tier two project estimated at $32.2 million requiring a CCN.
Estimated in-service date is April 2027.
Purpose: Limit radial load to less than 20 MW and provide “looped service” to REC Rand substation.
Project is currently under ERCOT independent review.
ERCOT conducted a steady-state load flow analysis based on TPL-001-5.1 and planning criteria with no voltage, thermal, or unsolved power flow violations found.
Seven options evaluated with three proposed by REC and four by ERCOT.
Options 1 and 2 had thermal violations for N-1 contingency scenarios.
Options 3, 4, 4a, 5, and 6 selected for further evaluation.
Option 5 deemed infeasible due to Explorer switching station constraints; remaining options require a CCN and are feasible.
Plant maintenance outage evaluation showed no voltage violations, thermal overloads, or unsolved power flow violations for shortlisted options.
Long-term load serving capability analysis performed; Options 3, 4, and 4a performed similarly, while Option 6 had less capability.
All four shortlisted options (3, 4, 4a, 6) meet reliability criteria, REC planning criteria, and improve long-term load serving capability.
Option 3 is the preferred option: least expensive, fully addresses REC planning criteria, no reliability issues, improves operational flexibility, and enhances long-term load serving capability.
Congestion analysis (using 2023 RTP 2028 economic case) showed no new congestion within the study area.
Option 3 details:
Estimated cost $32.2 million
Service date April 2027
Involves new 138-kV switch yard between Explorer and Glen Pine 138-kV line with a new 138-kV line from Rand to the new switchyard, approximately 12.35 miles.
ERCOT protocol section 3.11..4.9(4) endorses this project to meet REC planning criteria.
EIR will be posted to MIS in October.
No audience questions; next presentation: Oncor Delaware basin stages 3 and 4, under ERCOT independent review.
5 - EIR Status Update – Delaware Basin Stages 3 and 4 Project - ERCOT - Tanzila Ahmed
Stage 1 upgrade completed in 2023, Stage 2 upgrade expected in 2026, Stage 5 upgrade under review.
Stage 3 involves a new 345-kV substation, double circuit 345-kV line from Riverton to Drill Hole, and transformer upgrades.
Stage 4 involves a double circuit 345-kV line from Sand Lake to Riverton.
Reliability analysis includes sensitivity analysis and planned maintenance outage evaluation.
Total of 20 voltage violations including 2 generation violations and 2 transformer violations, and 4 unsolved power flow issues identified. All solved by the proposed project.
Upcoming tasks: conducting congestion analysis, updating cost estimates, and providing further status updates.
6 - EIR Status Update – Venus Switch to Sam Switch 345-kV Line Project - ERCOT
Oncor submitted the project RFP in June, estimated cost is $118.9 million and will not require a CCN.
Project to be completed by May 2026.
Addresses post contingency thermal overloads on the Venus switch to Sam switch double circuit 345-kV line.
Project is currently under ERCOT independent review.
Study Assumptions
Using 2023 RTP for 2026 summer case, adding 730 confirmed load, maintaining 2023 RTP reserve levels.
Preliminary Results
Three voltage violations under N-1 conditions, seen also under G-1 and X-1.
Four thermal overloads under P1 and one under P7 conditions.
Options
Option 1: Oncor proposed project, upgrading various 345-kV lines totaling about 76 miles.
Option 2: Includes upgrades in Option 1 plus Venus switch to Navarro 345-kV line upgrade of 33.2 miles.
Preliminary Results for Options
No thermal or voltage violations in N-1 study for Options 1 and 2.
Thermal and voltage violations observed under G-1 and X-1 conditions.
Decrease in thermal violations seen, especially in Option 2.
Next Steps
Study additional project alternatives to satisfy ERCOT reliability criteria.
Perform evaluations on plan maintenance outage, long term load serving capability, generation addition and load scaling sensitivity, subsynchronous resonance assessment, and congestion analysis.
Timeline: Final recommendation expected in Q4 of this year.
Q&A:
Questioner: Sunil Dhakal, Lone Star Transmission
Question: Are there plans to look into 345-kV in the area?
Response: Potentially, evaluation ongoing.
Questioner: Harsh, Oncor
Question: Clarification on treating 345-kV overloads and 69-kV voltage issues separately.
Response: Evaluating solutions for Waxahachie area, particularly Wilmer project, considering additional generation resources and load in northern Dallas. Conclusions not yet solidified.
7 - ERCOT Independent Review Scope: Connell 345/138-kV Switch and Connell to Rockhound 345-kV Double-Circuit Line Project
Ben was unavailable to present; Robert Golan took over.
Project submitted by Oncor in June 2024.
Tier one project costing $110.62 million, requiring a Certificate of Convenience and Necessity (CCN).
Estimated in-service date: December 2026.
Addresses low voltages and thermal overloads expected by summer 2025 due to significant load growth in the western portion of Texas, primarily from the oil and gas industry.
Project includes various constructions and installations:
New Connell 345/138-kV switching station.
Two new Connell to Rockhound 345-kV lines (13 miles).
New circuitry and breakers at multiple existing switches.
Reconfiguration of existing connections within the studied areas.
Scope and study area: Western Texas counties focusing on Midland and Martin.
Will follow NERC TPL-001-5.1 and ERCOT planning criteria.
Timeline for final recommendation: Q4 of 2024, with status updates at future RPG meetings.
No questions from the audience; the presentation moved to the next agenda item on the Forty 345/138-kV switch rebuild project.
Rebuild project is estimated to cost $103.5 million.
The project addresses thermal violations, replaces aging infrastructure, and enhances system reliability.
Existing switching station details: 345-kV double bus double breaker configuration, 138-kV single bus with 345/138-kV auto transformer rated at 750 MVA.
New switch configuration will be in a breaker-and-a-half layout.
Installation of a second 750 MVA auto transformer and a 110.4 MVAR capacitor bank at Forney was proposed.
Main driver of the project is the thermal violations observed at the existing Forney auto transformer.
Existing infrastructure at Forney was built in the 1960s and lacks modern microprocessor relays.
Rebuild scope: 345-kV equipment rated at 5,000 AMP, 138-kV equipment rated at 3,200 AMP, new auto transformer rated at 750 MVA, and relocation of the Forney substation.
Reactive support needs identified by real-time operational data showing low voltages in Dallas and Kaufman County.
Capacitor banks proposed to address low voltage issues not captured by models but observed in real-time operations.
Operational feedback prompted the reactive support installations to maintain system voltage around one per unit.
No further questions from attendees after the presentation.
Oncor presented an overview of the Wilmer 345/130-kV switch project.
The project aims to establish a 345/130-kV switch in Dallas County, referred to as Wilmer Switch.
Projected cost: $158.2 million.
Purpose: Address large load request of 756 MW at Wilmer 130-kV substation, preventing thermal violations and enhancing network reliability.
Location selection criteria: Proximity to load request and economic viability.
Project includes: Establishing a new 345/130-kV switch and two new transformers, terminating certain lines into Wilmer Switch, and rebuilding portions of the existing Watermill 345 kV line.
Rebuild and convert existing 69 kV line from Wilmer to Ferris to 130 kV operation.
Confusion addressed on how interconnection agreements are signed: Explained that agreements are contingent on approval and customers are informed of required upgrades. Load does not come online until 2026.
End use classification of the load: Data center, non-crypto.
ERCOT independent review study scope for the Wilmer 345/138 kV switch project presented by Yin Li.
Described overload issues in the Wilmer area due to new load, including Wilmer, Watermill, Seagoville, Forney, Kaufman, and the south area.
Oncor's proposed solution: Wilmer 345/138 kV project with two transformers and transmission upgrades.
Study assumptions, including region focus (North Central weather zone), use of 2033 RTP and 2028 thermal peak case for data.
Transmission projects with in-service dates before summer 2028 and relevant additions and removals detailed in appendices A and B.
Generation projects included based on August GIS report and adhering to 2023 RTP methodology.
Load assumptions include an additional 756 MW new confirmed load at Wilmer.
Contingency and criteria adherence, including techniques like need analysis, sensitivity analysis, SSR assessment, and congestion analysis.
Timeline goal to complete the study by December.
Question raised about performing dynamic stability studies for the large new load. Oncor confirmed no stability issues were found.
Clarified that ERCOT relies on TSP's stability study results unless specific stability issues are identified.
Confirmation that necessary stability studies were performed by Oncor, with a request to specify dynamic models used.
Yang Zhang (WETT) highlighted the importance of naming and organizational clarity for meeting minutes.
Further comment from another participant emphasized the need to reassess if the RPG study results match TSP studies, regarding the need for dynamic stability studies.
Conclusion with an acknowledgment of no more questions, and the next item handed back to Oncor for the Delaware Basin stage five project overview.
Presentation by WETT on Delaware Basin Stage 5 project alternatives.
Background: Need for system upgrades in the Delaware Basin to serve oil and gas loads identified in 2019. ERCOT 2023 RTP study confirmed this need.
Oncor submitted its proposal in May; WETT submitted an alternative in June, with a final version in August.
WETT's proposal is a Tier 1 project, with a portion to be in service by December 2028.
Cost for WETT's portion: $305 million.
WETT's proposal vs. Oncor's: Focus on using local 130 kV facilities to address load-serving needs while avoiding Lamesa area reliability issues.
Comparison: WETT offers a potentially more cost-effective solution, with similar performance in power flow, stability, and short circuit analyses as Oncor's proposal.
Conclusion: Both proposals solve reliability needs; WETT suggests ERCOT compare and review both to decide the best approach.
No questions were raised after the presentation. The next session will be an independent review scope presentation by ERCOT.
