- OpenDSS - The OpenDSS is a comprehensive electrical power system simulation tool primarly for electric utility power distribution systems. It supports nearly all frequency domain (sinusoidal steady‐state) analyses commonly performed on electric utility power distribution systems.
- GridLab-D - GridLAB-D™ is a new power distribution system simulation and analysis tool that provides valuable information to users who design and operate distribution systems, and to utilities that wish to take advantage of the latest energy technologies. It incorporates the most advanced modeling techniques, with high-performance algorithms to deliver the best in end-use modeling. GridLAB-D™ is coupled with distribution automation models and software integration tools for users of many power system analysis tools. Source code here
- PowerWorld Simulator - PowerWorld Simulator is an interactive power system simulation package designed to simulate high voltage power system operation on a time frame ranging from several minutes to several days. The software contains a highly effective power flow analysis package capable of efficiently solving systems of up to 250,000 buses. [Commercial, Free for educational use.]
- Siemens PSSE - PSS®E is a trusted leader in the power industry for cutting-edge electric transmission system analysis and planning. Used in over 115 countries worldwide, PSS®E is powerful, customizable, and fully-featured. With the addition of integrated node-breaker support in version 34, PSS®E is leading the market in advances in electric transmission modeling and simulation. [Commercial]
- GE PSLF - Effective power system analysis often requires large-scale simulations and manipulation of large volumes of data. When performing these analyses, efficient algorithms are just as important as the engineering models in which the data is used. GE Energy recognizes these imperatives, and has developed Concorda PSLF. The algorithms in the PSLF suite have been developed to handle large utility-scale systems of up to 80,000 buses. A complete set of tools allows the user to switch smoothly between data visualization, system simulation, and results analysis. [Commercial]
- GridDyn - is an open-source power transmission simulation software package developed at Lawrence Livermore National Laboratory. The name is a concatenation of Grid Dynamics, and as such usually pronounced as "Grid Dine". It was created to meet a research need for exploring coupling between transmission, distribution, and communications system simulations.
- PLC Fiddle - Free Online Ladder logic Editor and Simulator in your Browser. Description
- OpenPLC Project - It is a standard industrial controller, with sturdy hardware and real time response. It can be programmed with all the five standard PLC languages (ST, IL, SFC, FBD and Ladder), making it compatible with programs written for other PLCs
(creative commons license)