OpenDSS Designer

For years I have wanted a way to draw a one-line diagram of an electrical distribution system and just solve it, without the two options I actually had: expensive commercial packages like ETAP, or free tools like OpenDSS-G that are powerful but hard to use and Windows-only. OpenDSS itself, EPRI’s open-source solver, is excellent, but you drive it by writing scripts.

So over one week, working with Claude, I built the tool I wanted. OpenDSS Designer runs in your browser: place a source, a transformer, a busbar and some loads, wire them up, press Solve, and the voltages and loading appear on the drawing. Every solve runs the real OpenDSS engine. It reads and writes standard .dss files, runs daily or yearly time-series studies, and pulls in public load and solar data.

It is open source under the AGPL, and anyone can install it with pip install opendss-designer and run it locally with no limits. If you would rather it just work, the hosted copy at opendssdesigner.ryanmsparks.com is free with modest limits. If you need more, a Pro plan lifts the limits at $20/year to cover hosting and basic costs, not to make money.

Documentation is at opendssdesigner-docs.ryanmsparks.com, and the code is on GitHub. Try it, break it, and tell me what is missing.