This repository contains the LaTeX source for the STEPSS documentation — models reference and user guide.
STEPSS (Static and Transient Electric Power Systems Simulation) is an open-source power system simulation tool for dynamic studies of electrical grids. It performs power flow computations and simulates the dynamic response of power systems to disturbances under the phasor approximation.
STEPSS consists of three tightly integrated modules:
| Module | Full Name | Description |
|---|---|---|
| PFC | Power Flow Computation | Determines the initial operating point using the Newton-Raphson method in polar coordinates. Computes bus voltage magnitudes and phase angles, with optional transformer ratio adjustment. |
| RAMSES | RApid Multithreaded Simulation of Electric power Systems | Simulates the dynamic evolution of the power system. Supports Backward Euler, Trapezoidal, and BDF2 integration methods. Exploits OpenMP parallelism (up to 2 cores in the free version). |
| CODEGEN | CODE GENerator | Translates user-defined models from text descriptions into Fortran 2003 code for compilation and linking. Supports excitation controllers, torque controllers, injectors, and two-port components. |
The documentation is a modular LaTeX project. The main entry point is stepss_doc.tex, which includes the following chapters:
overview.tex— Quick overview of STEPSSinstall.tex— Installation instructionsnetwork.tex— Network modeling (buses, lines, transformers)ref_and_init.tex— Reference frame and initializationpfc-data.tex— PFC module data formatfiles.tex,solvsett.tex— File formats and solver settingsdisturbances.tex— Disturbance specificationdisc_cont.tex,sync_thev_impload.tex— Dynamic modelsuser_models.tex— User-defined models (CODEGEN)library_blocks.tex— Library of modeling blockscodegen/— Individual block definitions
Compile with pdflatex (run twice to resolve cross-references):
pdflatex stepss_doc.tex
pdflatex stepss_doc.texTwo pre-built PDFs are included, and they are kept identical:
stepss_doc.pdf— the build output ofstepss_doc.tex, and the copy published at stepss.sps-lab.org.userguide.pdf— the same document under the file name the Java GUI expects. It is bundled, together with the companion notes inmodels/, intoDOC.zipin stepss-java-ui and extracted at run time.
After rebuilding, refresh both, and regenerate DOC.zip in stepss-java-ui so the GUI ships the current guide.
The Java GUI documented in this guide runs on Windows 64-bit and requires:
- A 64-bit Java Runtime Environment, version 11 or later
- No separate installation needed: download
stepss.jarand run it directly; it self-extracts at startup
To compile user-defined models (CODEGEN) on Windows:
- Visual Studio Community 2019 or later (2022 recommended) with Desktop development with C++
- Intel oneAPI 2024.0 or later (Base Toolkit + HPC Toolkit), which provides the
ifxFortran compiler. The olderifortis deprecated and is no longer supported.
STEPSS is not Windows-only. RAMSES also builds on Linux and macOS with gfortran, and PyRAMSES installs with pip on Windows and Linux — see stepss.sps-lab.org.
- Maximum 1000 buses/nodes
- Maximum 2 processor cores for parallelisation
This guide — the LaTeX sources, the figures and the built PDF — is licensed CC BY 4.0. Share and adapt it freely, including commercially, with appropriate credit.
The software it documents is not. STEPSS is distributed under the Academic
Public License: free for non-commercial use (academic research, teaching,
non-profit organisations); commercial use requires contacting the authors, and
the free version is limited to 1000 buses and 2 cores. Those terms are
reproduced in legal.tex and printed at the front of the guide.
PFC and CODEGEN are owned by the authors. RAMSES is owned by the University of Liège (Belgium); the authors hold distribution rights.
See NOTICE.
- Dr. Petros Aristidou — petros.aristidou@cut.ac.cy
- Dr. Thierry Van Cutsem — thierry.h.van.cutsem@gmail.com