PJM MOD-026/027 Guidance

PJM’s MOD-026/027 Guidance: What Generator Owners Need Now—and How to Prepare for MOD-026-2

PJM has published clear expectations for how Generator Owners should verify and submit excitation/Volt-Var and governor/active-power models. The guidance goes beyond the baseline NERC MOD-026/027 requirements—especially for IBRs—and points to how industry practice is shifting ahead of MOD-026-2. This post distills what to do now, what PJM will look for in your package, and what to tighten in your internal procedure to be ready for the next revision. 

What PJM Expects Under MOD-026/027

Use models PJM will accept

PJM maintains an Acceptable Model List that aligns with NERC/ERAG practice and PJM experience. It specifies what’s acceptable, not accepted, and not recommended across generators, exciters, PSS, governors, renewable controls, load, and protection models. Submit generic models tuned to match unit performance; PJM may require a UDM if generics are insufficient. 

Include full IBR controls—and EMT benchmarking

All IBR facilities must provide an EMT model used to benchmark the positive-sequence phasor-based dynamic model. PJM also requires momentary-cessation behavior (thresholds/curves, recovery delay, active-current ramp rates, and any reactive-current limits). See the momentary cessation checklist in Appendix A-4 for exactly what to obtain from manufacturers. 

UDMs: no black boxes

If you submit a User-Defined Model, PJM requires:

• Structure, data, and closed-loop control logic (no black boxes)
  
  
• Implementations for both PSS®E and TSAT
  
  
• A generic model submitted alongside the UDM
  
  
• A DLL compatible with PJM’s current software—and an updated DLL within 30 days if PJM changes software versions

These expectations reflect R2.1.4 in MOD-026/027 and PJM’s added rigor.

Deliver a complete submittal package

File the case through the PJM Planning Community (Figure 2 in the guidance) and attach:

• .raw power-flow (PSS®E v35), covering equipment up to the POI; SLD recommended
  
  
• .dyr dynamics (PSS®E v35), including all control/limit models appropriate to unit type
  
  
• Lab test report (with signatures, MVA base, EIA-860 unit ID, model data in PSS®E format; comparison plots recommended)
  
  
• EMT model and documentation for IBRs
  
  
• Optional .lis DOCU output (for clarity)

PJM assigns a case number and targets processing within 90 days.

Self-review before you click “Submit”

PJM strongly recommends running a pre-submission test set (Table 1), including no-disturbance checks, 3-phase POI faults with trip/settling, exciter step tests, governor steps, LVRT/FRT checks, and frequency reference changes—many using built-in PSS®E BAT commands. Build these into your SOP so issues are found before PJM’s review. 

How PJM will grade you

PJM returns a usable or not usable determination. If not usable, you must respond under R3 within 90 days with corrected models and documentation via a new case; reasons for the finding will be provided. Final results post in the Planning Community. 

Why This Matters for IBR Modeling

PJM’s guidance formalizes plant-level control expectations (Volt/Var and active-power/frequency) for aggregated IBR models and insists on EMT-to-phasor benchmarking. It also asks you to explicitly document momentary-cessation behavior—low/high voltage entry curves, recovery delays, and active/reactive current recovery—which are critical to realistic ride-through studies. Expect this depth to be non-negotiable going forward. 

Looking Ahead: Implications for MOD-026-2

While the final text of MOD-026-2 is not yet in force, PJM’s requirements point to where industry practice is headed. Update your procedure now to align with likely themes:

• Phasor–EMT alignment: Treat EMT benchmarking as standard, not special—keep versioned EMT cases, parameter crosswalks, and side-by-side plotting baked into your evidence trail.
  
  
• Explicit IBR ride-through behavior: Maintain plant-specific momentary-cessation parameters and recovery ramps as configuration-controlled data, just like protection settings.
  
  
• Rigor in UDM governance: Maintain source-controlled DLLs for PSS®E/TSAT, closed-loop block diagrams, and rapid re-compiles when tool versions change.
  
  
• Tighter integration with event monitoring: Expect stronger ties between model validation and disturbance data (e.g., PRC-028/030 programs). Use event data to periodically re-validate models and document changes.
  

Update Your Internal MOD-026/027 Procedure—Now

Use this checklist to harden your process and ensure a smooth transition to MOD-026-2:

• Model scope
  
  
  • Map each unit to an acceptable generic model; note any UDM need/justification.
    
    
  • For IBR plants, require EMT + phasor models and a repeatable benchmarking workflow.
    
    
• Artifacts & formats
  
  
  • Standardize PSS®E v35 .raw and .dyr deliverables; maintain a plant SLD library.
    
    
  • Mandate lab reports with signatures, MVA base, EIA-860 ID, and PSS®E-formatted data tables.
    
    
• IBR momentary cessation
  
  
  • Capture thresholds/curves (low & high voltage), recovery delay, active-current ramp, and any reactive-current limits, by inverter make/model and site configuration.
    
    
• Pre-submission testing
  
  
  • Institutionalize PJM’s self-review test suite (BAT scripts, LVRT/FRT checks, POI faults, governor/exciter steps). Archive inputs/plots side-by-side with model versions.
    
    
• Case handling
  
  
  • Template the Planning Community submittal, tracking IDs, and a 90-day response playbook for “not usable” outcomes under R3.
    
    
• Continuous improvement
  
  
  • Tie model maintenance to disturbance monitoring and performance watchlists (PRC-028/030). Re-run a light validation set after material plant changes or flagged events.
    

Where GridStrong Fits

GridStrong’s compliance platform combines automated model management with event data analysis so you can execute PJM’s expectations at scale and be MOD-026-2 ready:

• Automated MOD-026/027 workflow: Capture test plans, ingest field results, auto-tune models to measured curves, and generate audit-ready validation packages—designed for a seamless transition to MOD-026-2.
  
  
• IBR modeling at depth: Manage EMT and phasor models together, benchmark across PSCAD/PSS®E/TSAT, and store momentary-cessation parameters as configuration-controlled data.
  
  
• Event-to-model loop: Ingest DFR/PMU/SCADA/SER, identify events, compare measured vs. simulated response, and trigger corrective actions that feed back into MOD-026/027 documentation—aligned with PRC-028/030 obligations.
  
  
• Evidence management: Centralize .raw/.dyr/SLD files, lab reports, signatures, DLLs, and version histories with one-click exports for the PJM Planning Community.
  

Bottom Line

PJM has set a high bar for dynamic model verification—especially for IBRs—and its process provides a practical blueprint for where MOD-026-2 is likely headed. Elevate your internal procedure now with EMT benchmarking, explicit momentary-cessation data, rigorous UDM governance, and an event-driven validation loop. A compliance platform purpose-built for NERC compliance automation will reduce risk and shorten PJM review cycles. 

Request a Demo to see how GridStrong automates MOD-026/027 today and positions your fleet for MOD-026-2, PRC-028, and PRC-030.