A PSS/E exchange package is usually layered. The RAW file establishes the steady-state network. DYR records attach dynamic behavior to devices in that network. Sequence data adds the quantities needed for unbalanced fault analysis. None of the companion files can repair an inconsistent foundation.
RAW: the steady-state network case
A RAW file is a text representation of the PSS/E power-flow case. Its opening record declares values such as system base MVA, format revision and nominal frequency. Ordered sections then describe the buses and equipment.
- Bus records define the bus number, name, nominal kV, type, area, zone, owner, voltage magnitude and angle.
- Load and fixed-shunt records attach demand or admittance to a bus and ID.
- Generator records define machine dispatch, reactive output and limits, voltage schedule, regulated bus, MVA base and status.
- Branch records define non-transformer circuits, impedances, charging, ratings, metering end and status.
- Transformer records describe two- or three-winding units, winding ratings, taps, controls and pairwise impedances.
- Switched shunts, areas, zones, owners and other supported sections complete the network definition.
Record structure changes by PSS/E revision. A file declaring revision 35 is not valid input for software that only accepts revision 34, even if most equipment fields happen to look similar. The export target must match the receiver.
What a solved RAW export actually stores
When a solved case is exported, PSS/E can retain the state values represented in the network records, including bus voltage magnitude and angle and the active and reactive output assigned to machines. Those values give the imported case a solved or near-solved starting point when the topology and options match.
Calculated branch-end MW, MVAr, current, loading and losses are results of the network equations. They are normally recalculated after the case is read and solved; they are not extra branch fields to add to a standard RAW record. Similarly, a diagram's label positions and graphic routing do not belong in the RAW network format.
Preserve the solved inputs PSS/E stores, then compare newly calculated voltages, source output and flows after read-back. A separate comparison report can document the tolerance without altering the native file.
DYR: dynamic behavior attached to network devices
A DYR file contains dynamic-model records rather than buses and branches. Each record identifies a bus and device ID, names a model and supplies that model's parameters in the exact order expected by the PSS/E model library or user-written model.
Typical records can represent synchronous machines, exciters, governors, stabilizers, renewable electrical controls, plant controllers, composite loads and protection. The model name alone is not enough: parameter count, order, units and version compatibility must match the receiving PSS/E installation.
Why DYR imports fail
- The referenced bus, load ID or machine ID does not exist in the RAW case.
- The model is not supplied with that PSS/E version or its user-model library is missing.
- The record uses the wrong number or order of constants and integer parameters.
- A load model is attached as a machine model, or vice versa.
- Several models claim incompatible control roles for the same device.
The safest process is to use official model documentation and a known accepted example for the target release, then load the file and resolve every undefined or ignored record. Siemens' PSS/E overview describes its standard, vendor-specific and customizable dynamic-model capabilities.
SEQ: the sequence-data layer for fault studies
Positive-sequence power-flow data alone cannot represent every unbalanced fault. Sequence data provides negative- and zero-sequence impedances, grounding and neutral information and applicable machine or shunt quantities for short-circuit calculations.
The exact supported import workflow and record layout should be confirmed against the target PSS/E version. HV Power Flow calls its export a sequence-data companion because it must be read and validated with the corresponding RAW case in the receiving environment.
| Equipment | Sequence information to confirm |
|---|---|
| Utility source | Positive-, negative- and zero-sequence equivalents, X/R and grounding basis |
| Lines and cables | Negative- and zero-sequence impedance and charging on the correct base and length |
| Transformers | Winding connections, grounding, neutral impedance and sequence transfer path |
| Machines | Subtransient, transient, negative- and zero-sequence data as applicable |
| Inverter resources | Utility-approved fault-current representation and sequence behavior |
The files must describe the same case
Consistency is more important than the number of records. The same bus cannot be 34.5 kV in one file and 13.8 kV in another. A DYR model for machine ID G1 cannot attach to a RAW machine identified as 1. A grounded-wye transformer in the sequence data cannot be a delta winding in the network record.
Use a cross-file identity check
- List every bus number, name and nominal voltage.
- List every load, machine, line and transformer ID.
- Verify each DYR and sequence record resolves to exactly one steady-state device.
- Verify all per-unit values use their declared equipment or system base.
- Verify status, winding connections and control assignments describe the intended study scenario.
A practical pre-submission validation checklist
- The RAW header declares the intended PSS/E revision and base frequency.
- Every required RAW section appears in the correct order and terminates correctly.
- Bus numbers and device IDs are unique where the format requires uniqueness.
- The swing bus has a matching source or machine record and realistic limits.
- Two- and three-winding transformer records use the correct field layout and impedance bases.
- The imported RAW case solves to the intended operating point.
- Every DYR record is recognized and attached to the intended device.
- Sequence data loads without unmatched equipment and representative faults produce plausible results.
- Warnings, preliminary values and assumptions are documented outside the native files.
Passing a local structural validator is useful, but the decisive test is a clean read, initialization and study run in the utility's target PSS/E release.
How HV Power Flow handles the package
HV Power Flow exports the native steady-state fields that belong in the selected RAW revision, supported DYR model records in deterministic parameter order and a sequence-data companion tied to the same equipment IDs. Readiness checks flag missing source, transformer, sequence and dynamic inputs before export. Utility and professional validation remain required.