Quick Start

STEPSS provides three ways to run simulations:

Interface	Dynamic Simulator (RAMSES)	Static Simulator (PFC)	CODEGEN
Command Line	`ramses -t cmd.txt`	`pfc -t cmd.txt`	`codegen model.txt`
GUI (Java)	Via STEPSS GUI	Via STEPSS GUI	Via STEPSS GUI
Python	Via PyRAMSES	—	—

Dynamic Simulation (RAMSES)

RAMSES Command-Line Interface

The RAMSES executable accepts the following arguments:

ramses.exe [-t command_file] [-v]

Flag	Description
`-t command_file`	Read inputs from a command file (non-interactive mode)
`-v`	Print version information and exit

Interactive mode (no -t flag): RAMSES prompts for each input sequentially:

Dump settings, comments and initialization data in file [press enter to skip] :
Disturbance file name [compulsory] :
Dump system trajectory in file [press enter to skip] :
Observable file name [compulsory] :
Dump continuous simulation trace in file [press enter to skip] :
Dump discrete simulation trace in file [press enter to skip] :

Non-interactive mode (-t flag): The command file provides the same inputs as lines, in order:

Prepare data files: Network data, dynamic data, solver settings, LFRESV (power flow solution)
Create a command file (cmd.txt):
```
data.dat volt_rat.dat settings.dat

disturbance.dst
result.rtrj
obs.obs
cont.trace
disc.trace
```
The command file contains, in order:
- Data files (one or more, space- or newline-separated) — read until a blank line
- Initialization dump file (blank line to skip)
- Disturbance file (required)
- Trajectory file (blank line to skip)
- Observables file (required if trajectory file is given)
- Continuous trace file (blank line to skip)
- Discrete trace file (blank line to skip)
Run the simulation:
Terminal window
```
ramses.exe -tcmd.txt
```
Process results: Use PyRAMSES extractor, MATLAB, or other tools to read the trajectory file

Launch STEPSS by double-clicking stepss.jar
Load a test case: Use File → Open to load your data files
Run Power Flow: Execute PFC to compute the initial operating point
Configure Simulation: Set solver parameters and define disturbances
Run Dynamic Simulation: Execute RAMSES and observe results
Analyze Results: Use the built-in plotting tools to visualize voltage, frequency, and power traces

The GUI coordinates PFC and RAMSES through lock files (.lock_RAMSES, .kill_RAMSES) for graceful process management.

For detailed GUI usage, visit the STEPSS website.

Install PyRAMSES:
Terminal window
```
pip install pyramses
```

Run a simulation:

import pyramses

# Configure the case
case = pyramses.cfg()
case.addData("data.dat")
case.addData("volt_rat.dat")
case.addData("settings.dat")
case.addObs("obs.obs")
case.addDst("disturbance.dst")

# Run
ram = pyramses.sim()
ram.execSim(case, 150.0)

Extract and plot results:

ext = pyramses.extractor(case.getTrj())

# Plot bus voltage magnitude
ext.getBus('1041').mag.plot()

# Plot synchronous machine speed
ext.getSync('g1').speed.plot()

See the PyRAMSES API Reference for the complete interface.

PFC Command-Line Interface

The PFC executable accepts the following arguments:

pfc.exe [-t command_file] [-o output_file] [-c trigger_file] [-v verbosity]

Flag	Description
`-t command_file`	Read inputs from a command file (non-interactive mode)
`-o output_file`	Redirect output to a file instead of the console
`-c trigger_file`	Cycle mode — wait for trigger file to start/proceed
`-v N`	Verbosity level (0 = silent, 1 = normal)

Interactive mode (no -t flag): PFC prompts for data files, then presents a command menu.

Non-interactive mode (-t flag): The command file provides data file names (one per line, blank line to end), followed by menu commands.

Prepare data files: Network data, PFC-specific data (generators, loads, SVC, LTC-V, PSHIFT-P)
Create a command file (pfc_cmd.txt):
```
network.dat
pfc_data.dat

VT
volt_rat.dat
E
```
Run the power flow:
Terminal window
```
pfc.exe -tpfc_cmd.txt -ooutput.txt
```

After loading data and solving, PFC presents these commands:

Command	Description
`P`	Take new control parameters from file
`D`	Display output values
`1`	Display outputs on 1-line diagram (SVG)
`M`	Modify system (change loads, generators, topology)
`RI`	Reset system to initial configuration
`CA`	Perform contingency analysis
`CL`	Check operating limits (voltage bounds, branch overloads)
`O`	Change output file
`DF`	Update all records and dump them to a file
`VT`	Generate a file with voltages and adjustable transformer ratios (LFRESV format)
`S`	Save operating point and Y matrix to MATLAB file
`E`	Exit

The VT command produces the LFRESV file needed to initialize RAMSES.

Launch STEPSS by double-clicking stepss.jar
Load data files: Use File → Open to load network and PFC data files
Run Power Flow: Click the PFC button to compute the power flow
Inspect results: View bus voltages, branch flows, generator outputs, and reactive power limits
Export LFRESV: Save the power flow solution for use with RAMSES