TVA Interconnection Module Package

Stage 1: Cluster Request Window and Customer Engagement Window

• Support you in preparing the Interconnection Request (LGIP Appendix 1 and its Attachment A workbook) for submittal through TVA's IC Portal within the annual Cluster Request Window, including the Generating Facility Capacity, the requested Interconnection Service level, the choice of Energy Resource or Network Resource Interconnection Service, and the Point of Interconnection. We prepare the technical content; you submit.
• Develop the plant-specific PSS/E version 35 benchmark case required by TVA Modeling Requirements Revision 5 Section 2.1.1, with equipment data matching the Interconnection Request, the original equipment manufacturer (OEM) de-rate curves for temperature and elevation, and the system equivalent generator and Thevenin branch set to the short circuit ratio TVA specifies at the Point of Interconnection.
• Develop plant dynamic models per TVA Modeling Requirements Section 2.1.2: for inverter-based resources, both the OEM user-defined models with compiled .dll files and the second-generation generic renewable models (REGCAU1, REECAU1 or REECCU1, REPCAU1, or PLNTBU1 with REAX_BU1 for hybrid plants), each in its own DYRE file, plus models of any static var compensator (SVC) or static synchronous compensator (STATCOM); for synchronous resources, PSS/E generator, exciter, power system stabilizer and governor models with a report listing the models and their parameter settings.
• Perform the simulations TVA Modeling Requirements Section 2.1.3 requires with both the generic and the user-defined models at a quarter-cycle time step (no-disturbance drift run and bolted three-phase fault at the Point of Interconnection for each applicable solar, wind and storage operating scenario), produce the simulation output files, and complete the TVA Modeling Requirements Appendix I checklist.
• Coordinate with inverter, turbine and plant controller manufacturers on the plant-specific PSCAD EMT model you obtain from them, compatible with PSCAD version 5 or higher, with the user manual, sample implementation test case, OEM statement of acceptable time steps and settings identification TVA requires in Modeling Requirements Section 2.1.4.
• Run the TVA Modeling Requirements Appendix III Model Quality Checks on the PSCAD model (drift run, time step checks, voltage step checks, frequency step checks, and three-phase-to-ground and two-phase-to-ground disturbance tests at a short circuit ratio (SCR) of 3 and X/R of 5) and complete TVA's PSS/E and PSCAD Modeling Report templates.
• Benchmark the generic, user-defined and PSCAD models against each other for the same disturbances, and collect the OEM model benchmarking report and the user-defined and EMT model user manuals TVA Modeling Requirements Appendix II lists.
• Run TVA's optional self-check Model Tools (the IBRDC_Hammer PSS/E script and the TVA PSCAD Test Module) before submittal, and prepare the package for TVA's Optional Pre-Application Review when you elect it.
• For Generating Facilities with storage, document the requested charging operating assumptions and the control technologies that will hold the plant to them.
• Support you at the Scoping Meeting on alternative Points of Interconnection and configurations, refine data and models, respond to TVA deficiency notices, and update models for modifications the LGIP permits before the Cluster Study Agreement is returned.

Stage 2: Cluster Study, Cluster Restudy and Interconnection Facilities Study

• Review the Cluster Study Report and any Cluster Restudy Reports (power flow, stability, short circuit, EMT and reactive power capability results) against the plant models, using the study databases TVA provides on request, and identify plant-side mitigation such as control tuning or reactive devices.
• Develop a detailed collector system load flow model and perform a reactive capability study against LGIA Article 9.6.1.
• Support you at each decision point: remaining in the Cluster after the Cluster Study Report Meeting and each Cluster Restudy Report Meeting, and executing the Interconnection Facilities Study Agreement with the required technical data.
• Prepare revised steady-state data, single-line diagram and dynamic models for modifications permitted before the Interconnection Facilities Study Agreement is returned, including technological advancement requests under LGIP Section 4.4.6.
• Review the technical content of the draft Interconnection Facilities Study Report and prepare comments for you to submit.
• Respond to TVA data requests on the plant models throughout the studies.

Stage 3: LGIA, Construction and Backfeed

• Review the technical requirements in LGIA Appendix C (Interconnection Details), including voltage regulation, power factor, primary frequency response, ramp rate, grounding and protection, against the plant design and models.
• Review inverter and plant protection settings and the plant's voltage and frequency ride-through capability curves at the Point of Interconnection against LGIA Article 9.7.3, LGIA Appendix C and the No Trip Zones in TVA ESF Interconnection Requirements Rev 0002 Sections 3.4 and 3.5.
• Prepare the updated information submission of LGIA Article 24.3, including the completed Appendix 1 data and stability models compatible with TVA standard models, and develop a standard model where no compatible model exists if TVA and you agree on us as the consultant.
• Update the generic and user-defined PSS/E models and the PSCAD EMT model to as-designed plant data and settings for the Post-Construction/Backfeed stage, with inverter and plant controller setting sheets, a Plant Controls Narrative, the Appendix IV PSCAD Model Quality and Performance Tests (the Appendix III tests with disturbance tests at an SCR of 3 and X/R of 5 and at the actual site all-ties-closed and strong-source-out conditions, plus ride-through, SCR change and voltage protection tests), and the inverter short circuit and harmonic source data, for submittal before backfeed per TVA Modeling Requirements Section 2.2 and the IBR Commissioning Guidelines, and no later than LGIA Appendix C Section 6.2 requires.
• Compile transformer test report data, including zero sequence impedance and the main step-up transformer no-load test results, and the as-built gen-tie, collector system and ground grid design data TVA requires for the short circuit, grounding and EMT power quality models.

Stage 4: Trial Operation, Commissioning, 14-Day Burn-In and Commercial Operation

• Update the generic, user-defined and PSCAD models with the parameters tuned during commissioning (as-designed-with-modifications) for the 14-day Burn-In stage, update the Plant Controls Narrative, and compile the inverter and plant controller OEM attestation reports and the plant model attestation report TVA Modeling Requirements Section 2.3 requires, for submittal before the scheduled Commercial Operation Date.
• Support the modeling review TVA requires to pass before granting the Commercial Operation Date.
• Support the commissioning performance tests TVA performs or observes under its IBR Commissioning Guidelines (primary frequency response, harmonic distortion, reactive power capability, voltage flicker, voltage step and, during the 14-day burn-in, voltage regulation, plus the battery energy storage system (BESS) capacity and interoperability tests), the reactive capability testing of LGIA Appendix C Section 4.4.4 and, for synchronous units, the open circuit step voltage test under LGIA Article 24.4.
• Prepare the as-built and as-tested information LGIA Article 24.4 requires before the Operation Date, then validate the generic, user-defined and PSCAD models against commissioning test data and deliver the Post-COD As-Built Package (validated as-built models, model validation report and final OEM model benchmarking report) after the Commercial Operation Date per TVA Modeling Requirements Section 2.4.
• Prepare the MOD-025, MOD-026, MOD-027, MOD-032 and PRC-024 model and data submittals on TVA's Interconnection Customer NERC (North American Electric Reliability Corporation) Compliance Checklist for you to submit before the Commercial Operation Date; the TVA checklist still cites MOD-027-1, which MOD-026-2 replaced on April 1, 2026.

Stage 5: Post-COD Periodic Model Evaluations

• Update the generic, user-defined and PSCAD models and setting sheets after changes to equipment, settings, firmware or protection, which you coordinate with TVA before implementing, and validate the models against system event data and in the five-year periodic verification and validation TVA Modeling Requirements Section 2.5 requires, for you to submit to TVA.
• Support you in evaluating plant changes that would require a new Interconnection Request for a capacity increase or Material Modification, or a Surplus Interconnection Service request, and prepare the updated models.