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Getting started

Install

OpenDSS Designer is a Python package; it needs Python 3.10 or newer.

pip install opendss-designer
opendss-designer

This starts a local web server and opens the editor in your browser. Useful flags: --port 8721 (it picks the next free port if busy) and --no-browser.

The app is fully local: the server binds to 127.0.0.1, and your circuits never leave your machine.

Try the demo circuit

Click Open and load examples/demo-substation.oneline.json from the repository, then press Solve to see the result overlays immediately.

Draw your first circuit

  1. Place elements — click an element in the palette (Source, Busbar, Transformer, Breaker, Load, Capacitor, Generator, PV system, Storage…), then click the canvas to drop it. Placement is sticky: keep clicking to drop several; press Esc to stop. Each palette item has a keyboard shortcut letter — see Components for the full reference.
  2. Wire them up — drag from one terminal to another. You'll be asked whether the connection is a Wire (an ideal connection that merges the two buses) or a Line (a real OpenDSS Line with impedance and length). Illegal connections are refused with an explanation.
  3. Set parameters — select an element and edit its OpenDSS parameters in the properties panel: kV, kVA, impedances, phases (1/2/3), wye/delta connection, load model, and so on. Lines can start from conductor presets.
  4. Watch the validation — unconnected terminals, a missing source, islands, duplicate names, and kV mismatches are flagged live; errors halo the offending element and disable Solve until fixed.

Solve

Press Solve to run a snapshot power flow through the real OpenDSS engine. The results overlay the diagram:

  • bus voltages in per-unit at every busbar,
  • element loading as pie charts with percentages,
  • power flows, and total losses in the status bar,
  • violations color-coded: undervoltage blue, overvoltage/overload red.

Toggle Auto to re-solve automatically after every change. The Graph tab in the bottom panel plots solved results — pick your axes to get, for example, a classic voltage-profile plot along the feeder. The Fault overlay and Losses tab cover short-circuit currents and per-element losses — see Solving & analysis.

Simulate over time

Snapshot solves are one operating point. To simulate a day or a year — loads following demand curves, PV following the sun, storage dispatching — assign shapes in the Shapes tab (draw them, paste CSV, or import real NREL/NLR building profiles and NSRDB irradiance), switch the toolbar to Time series mode, and press ▶ Run. Then scrub or play through the results directly on the diagram. See Shapes & profiles and Time-series analysis.

Save, export, import

  • Save/Open stores the whole project (diagram + parameters) as a .oneline.json file.
  • Export writes a runnable .dss script — the exact commands the built-in solver uses — so anything you draw also runs in stock OpenDSS.
  • Import loads existing .dss files; see Importing DSS files.

Editor essentials
Undo / redo Ctrl+Z / Ctrl+Y
Copy / paste Ctrl+C / Ctrl+V
Delete selection Del
Stop placing Esc

Plus: grid snapping, pan/zoom with a minimap, box-select and group-move, right-click context menu, rotation, and double-click actions — double-click a breaker to open/close it, or a wire/line to add a draggable routing point.