Power flow

NumaSim can solve the steady-state power flow of your electrical circuit alongside the time-domain simulation. Use it to size a network, check bus voltages under load, or validate a PSS®E case before streaming it into a transient run.

When to use it

A time-domain simulation answers "what is the voltage at this node right now?". A power-flow solve answers "what is the steady-state voltage at every bus, given the loads and generation specified?". They complement each other:

• Run power flow first to verify your network is feasible.
• Then run a transient simulation to see how it responds to a disturbance.

Solving a power flow

1. Build (or import) an electrical circuit with buses, branches, generators, and loads.
2. Open the Power Flow dialog from the toolbar.
3. Pick the solver (Newton-Raphson is the default; Gauss-Seidel and fast-decoupled are available).
4. Click Solve. The dialog reports per-bus voltage magnitude and angle, slack bus power, and any convergence issues.

Visualizing the result on the canvas

When a power-flow solution is loaded, every bus and branch on the canvas can display an overlay (voltage magnitude / angle, line MW / MVAR flow). Toggle the overlay from the dialog's footer.

Importing PSS®E cases

If you already have a network in PSS®E .raw format, use File > Import PSS/E. The importer reads the raw file and lays out an equivalent circuit on the canvas. The bundled samples/ieee9 case is the IEEE 9-bus benchmark imported this way.

See also

• Sample: IEEE-9 for a worked example.