SimPowerSystems 5.2

Simulation Capabilities

SimPowerSystems provides three solution methods for your power system network as well as an ideal switching algorithm that improves simulation performance for systems with high-frequency switching.

With SimPowerSystems, you can use the variable-step integration algorithms in Simulink to perform highly accurate simulations of power system models. Some of these integration algorithms handle the numerically stiff systems that often arise in modeling real power systems. The zero-crossing detection capabilities of Simulink let you detect and solve discontinuities with full machine precision.

Discretization simulates your system with fixed time-step trapezoidal integration. It is especially effective for power system models that include power electronic devices. This mode also facilitates the execution of your model in real time.

Phasor simulation replaces the differential equations representing the network with a set of algebraic equations at a fixed frequency. Phasor simulation facilitates transient stability studies of systems with multiple machines.

The ideal switching algorithm in SimPowerSystems enables fast and accurate simulation of systems containing power electronic devices. This algorithm uses an improved method of calculating the state-space representation of the system instead of relying on current sources with high-impedance snubbers to model power electronic devices. This method gives you greater flexibility in selecting a solver and results in shorter simulation times.

Power System Analysis Methods

SimPowerSystems provides system analysis tools that enable you to:

• Display steady-state voltage and currents
• Display and modify initial state values
• Perform load flows and machine initialization
• Display impedance vs. frequency measurements
• Generate a report of the steady-state calculations

The SimPowerSystems graphical user interface displays steady-state values of measured current and voltages and all state variables, including inductor currents and capacitor voltages.

SimPowerSystems PowerGUI dialog box. The buttons are used to run key power system analyses. Click on image to see enlarged view.

The load flow computational engine computes initial currents of synchronous and asynchronous machines. You specify the desired steady-state machine conditions in your circuit. SimPowerSystems then computes the load flow. The resulting rotor position, initial currents, and internal fluxes are automatically entered into the parameters for the machines.

SimPowerSystems lets you analyze the electrical network topology and compute the equivalent state-space model of your circuit without running a simulation. You can link the state-space model to the LTI Viewer interface in Control System Toolbox™ to obtain time-domain and frequency-domain responses.