Power Systems ARTS

Services · Simulation

WPSTAB

A quasi-steady-state power systems simulation program, developed in the National Technical University of Athens under the guidance of Professor Costas Vournas.

The method

Built for the timescale voltage collapse actually happens on

Long-term voltage instability develops over minutes, driven by load recovery, tap changers and generator field-current limiters — not over the first seconds after a fault. Full electromechanical simulation is an expensive way to study that timescale.

Quasi-steady-state simulation represents the fast dynamics by their equilibrium and integrates only the slow ones. The result is a time-domain method fast enough to run the number of scenarios that long-term stability assessment requires.

PV curve from a WPSTAB long-term simulation. Bus voltage falls as area load rises, turns back at the nose just below 1200 MW and drops away as the load continues to be restored.
PV curve — voltage against area load, turning at the nose
The WPSTAB main window, showing the menu bar and the network report for a loaded case: 74 buses, 44 transmission lines, 50 transformers and 20 generating units.
WPSTAB 7.3.02 — network report for a loaded case
Bus voltages against time from a WPSTAB long-term simulation. Three traces decline over three minutes in small steps as tap changers operate.
Long-term simulation — voltages stepping down as tap changers act

Capabilities

What the program does

Simulation

QSS time domain

A fast time-domain method well suited to the analysis of long-term voltage stability phenomena.

Plotting

PV and QV curves

Wide plotting capabilities, including PV and QV curves and time-responses for any monitored quantity.

Analysis

Sensitivities and eigenvalues

Advanced calculation features: sensitivity analysis, and eigenvalue and eigenvector analysis.

Models

Model library

Distributed energy resources, protection equipment and generator controllers.

Want to see WPSTAB run on your network?

We can demonstrate the program against a case from your own system.

Request a demonstration