APS Interconnection Module Package

Stage 1: Cluster Request Window, Customer Engagement Window and Cluster Study Phase 1

• Guide you through the Interconnection Request contents in LGIP Section 3.4.1.1 (Appendix 1 application, Site Control, Commercial Readiness Deposit, Point of Interconnection, Network Resource Interconnection Service (NRIS) or Energy Resource Interconnection Service (ERIS) election, and storage charging operating assumptions) and through APS deficiency notices; you submit the request through the APS PowerClerk portal.
• Assemble the generator interconnection data package listed in Table 1 of the APS Application Requirements Business Practice: Inverter Based Resource Data Sheet, single-line diagram, site layout, manufacturer spec sheets with ambient temperature and elevation derating, and P-Q diagrams (four quadrants for storage).
• Develop the site-specific power flow model (.epc) and dynamic model (.dyd) in GE PSLF format as a detailed equivalent from the generator terminals to the Point of Interconnection, following the equivalent modeling guidelines of the Western Electricity Coordinating Council (WECC) and the APS power flow checklist (control mode, Pmax, turbine and fuel type codes, station service load, transformer taps).
• Build the generic library root-mean-square (RMS) dynamic model, with block diagrams of the inverter and plant controls, from Table 1 of LGIP Attachment A to Appendix 1 (or another WECC-approved model), and assemble the validated user-defined RMS model with its validation attestation. Use the WECC-approved plant controller model for plants with multiple generator equivalents (WECC has retired repc_b), enable voltage control and frequency response, and set the voltage and frequency ride-through models to the actual equipment settings.
• Run the APS flat run and bump test (three-phase fault at the Point of Interconnection with APS standard clearing times) for all operating scenarios and document the results.
• Perform the 0.95 power factor (reactive power) analysis with the APS method of two fictitious synchronous condensers and size any switched shunt capacitors planned in the collector system.
• Develop or assemble the PSCAD electromagnetic transient (EMT) model and its documentation and review it against the APS Checklist for Reviewing Model Submission and PSCAD Model Supplier Checklist.
• Coordinate with inverter, turbine and plant-level controller manufacturers to obtain PSLF and PSCAD models, parameters and model documentation.
• Support the Scoping Meeting with technical data on the Point of Interconnection and alternatives, review the Phase 1 Report, and support your continue-or-withdraw election after the Phase 1 Report Meeting.

Stage 2: Cluster Study Phase 2 and Phase 3 (Cluster Re-Studies)

• Review the Phase 2 Report (stability, short circuit, power factor and short circuit ratio results) and identify model-related causes of any instability or ride-through failure.
• Provide modeling support over the course of Phase 2 and any Phase 3 Cluster Re-Study to resolve plant instability identified in the stability analysis, including control tuning, reactive device changes and updated models.
• Screen the project against the APS EMT study screening criteria in Section 4.5 of the APS Technical Interconnection Requirements for IBRs (TIR) and support any EMT study APS performs.
• Evaluate modifications permitted under LGIP Section 4.4 and prepare the revised Appendix 1 data and updated models that must accompany a modification request or an APS Material Modification evaluation under the APS Material Modifications Business Practice, including the analysis for a technological advancement request under LGIP Section 4.4.6.
• Review re-study results to support your decisions at the Phase 2 and Phase 3 decision points, including the one-time NRIS to ERIS change APS allows before Phase 3 begins.
• Prepare responses to APS data requests during the Cluster Study.

Stage 3: Interconnection Facilities Study (Cluster Study Phase 4), LGIA and Construction

• Prepare the technical data required with the executed Interconnection Facilities Study Agreement.
• Review the draft Interconnection Facilities Study Report and prepare technical comments for you to submit within the LGIP Section 8.3 comment period.
• Support you on the technical content of the draft LGIA appendices, including Appendix C interconnection details and control technologies.
• Prepare the LGIA Article 24.3 updated information submission: the completed Appendix 1 Generating Facility data with final equipment selections and models compatible with APS standard models.
• Prepare the Power Plant Controller controls narrative support material and perform the Initial Model Testing milestone of the APS IBR Business Practice on the steady-state, positive-sequence dynamics and EMT models to show compliance with the TIR.
• Run the TIR Table 4-1 tests in PSCAD and PSLF and benchmark the positive-sequence model against the EMT model per TIR Section 4.2.5.
• Coordinate with equipment manufacturers on the equipment model quality attestations (E-MQA) and prepare the plant model quality attestation (P-MQA) material required by TIR Section 4.2.4.3.

Stage 4: Energization, Commissioning and As-Built Models

• Update the PSLF and PSCAD models and the short circuit data to as-built design parameters for the LGIA Article 24.4 information supplementation before the Operation Date.
• Prepare the As-Built Technical Documentation and Verified Models and As-Left Settings milestones of the APS IBR Business Practice, with as-left Power Plant Controller, inverter and relay settings implemented in the PSLF and PSCAD models.
• Review inverter and relay protection and ride-through settings against the TIR and the North American Electric Reliability Corporation (NERC) ride-through standard that applies to the facility (PRC-029 for inverter-based resources, PRC-024 for synchronous and Type 1 and 2 wind units), including the PRC-024-2 and PRC-029-1 references in the APS testing documents.
• Support you and your performance testing consultant on the commissioning tests in the APS Performance Testing and Compliance Guidelines for Solar PV or BESS (photovoltaic or battery energy storage system), including active and reactive power capability (MOD-025), voltage control modes (MOD-026), primary frequency response (MOD-027) and fast frequency response, with model simulations for comparison against field results.
• Support the IBR Performance Requirements Test Report that you provide to APS.

Stage 5: Post-Commissioning Model Validation and Updates

• Validate the PSLF and PSCAD models against field test data and prepare the validated models, model validation reports and NERC MOD-025, MOD-026 and MOD-027 reports due within one year after the Commercial Operation Date (COD) under the APS IBR Business Practice (the APS IBR Business Practice still cites MOD-027-1, which MOD-026-2 replaced on April 1, 2026).
• Update models and settings documentation after equipment replacement, repair or adjustment for the LGIA Article 24.4 post-Operation Date information updates.
• Evaluate proposed changes to IBR control settings or equipment against the APS FAC-002-4 R6 Qualified Change definition and the restudy triggers in TIR Section 4.6, and prepare the data and models you submit so APS can determine under LGIP Section 2.1 whether a Generating Facility Modification is a Material Modification.
• Support the routine performance tests in Section 3.3 of the APS IBR Business Practice with updated model simulations.