From a full transmission model to a clean, reduced study model — auditable and re-runnable.
Pillar-3 stability studies need a lean AC/DC model. Velon wraps a commercial solver reduction engine with Python orchestration and DPL scripting — boundary-busbar aware, fully reproducible — feeding directly into PSA, PFA and PVA.
The full network is collapsed everywhere it does not influence the study zone — while the study area and every boundary busbar are preserved exactly, so results stay defensible.
Our PowerFactory + Python automation starts at the point of interconnection and expands the retained boundary outward — bus by bus — re-checking the harmonic impedance against the full network at every step. It stops the moment the reduced model matches within the client's threshold, then outputs that study area for EMT.
The boundary sits one bus from the POI. Far too tight — the impedance match is poor, so the automation keeps expanding.
Match within threshold at POI + 6 buses. This area is exported as the EMT study model; the external network is replaced by a Ward / dynamic equivalent.
Large PowerFactory networks often carry more detail than an EMT study needs — but removing the wrong detail corrupts the electrical behaviour seen by the connecting asset. Velon's workflow preconditions the full network, reduces unnecessary modelling detail and validates the reduced study model before PSCAD conversion.
This is not a manual boundary cut. It combines voltage-dip analysis, harmonic-impedance scans, short-circuit checks, power-flow comparison and bottom-up network aggregation to retain the parts of the system that materially affect the POI.
Start from the full TSO or utility model — transmission, substation and lower-voltage detail where available.
Voltage-dip and harmonic-impedance scans identify the electrical area that must stay inside the EMT boundary for fidelity.
DPL and Python scripts retain the study zone and place validated equivalents beyond it — proven against the full model on power flow, short circuit and frequency scan.
Convert the validated retained study zone from PowerFactory into PSCAD EMT using PRSIM.
The compact EMT model for grid-connection studies, control-interaction, fault ride-through, harmonic performance and dynamic stability.
Before defining the EMT boundary, the full network is prepared for reduction. Velon's automation simplifies highly detailed substation models, aggregates feeder-level networks and collapses remote sections into equivalent representations — reducing model size without losing the impedance, short-circuit and voltage-response characteristics that matter at the POI.
The bottom-up approach starts at the lower voltage levels and progressively aggregates upwards. At each stage the reduced representation is checked against electrical indicators — equivalent impedance, short-circuit level and boundary power flow — so the model is made smaller without blindly removing electrically important parts of the system.
Run a three-phase fault at the POI (IEC 60909) and map residual voltages across the wider network. The voltage-depression footprint gives an analytical basis for how far the detailed study zone must extend.
Compare the impedance seen from the POI across the relevant frequency range. The reduced network must retain the key impedance and resonance characteristics of the full network — iterative Thévenin equivalents are accepted only while the spectrum holds.
Every reduction is proven against the full model on four electrical fronts before it is allowed forward to PRSIM conversion.
Active and reactive flows compared between the full and reduced PowerFactory models — confirming the operating point and boundary flows are preserved.
Short-circuit levels compared at selected busbars — especially the POI and nearby asset connection points — confirming the grid strength seen by the asset is preserved.
Harmonic impedance and network frequency-scan results compared at the POI — confirming resonance and impedance characteristics are retained before EMT conversion.
The POI fault study is re-run and the residual-voltage footprint compared — confirming the retained zone is large enough and the fault response is represented correctly.
The automation produces an auditable comparison report: power-flow deviation, short-circuit deviation at selected buses, impedance-scan deviation across frequency, and voltage-dip propagation. The report is the technical basis for the selected EMT boundary — and confirms whether the reduced model is suitable for PRSIM conversion into PSCAD.