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Powergui

Environment block for SimPowerSystems models

Library

powerlib

Description



The Powergui block allows you to choose one of the following methods to solve your circuit:

  • Continuous, which uses a variable step solver from Simulink®

  • Ideal Switching continuous

  • Discretization of the electrical system for a solution at fixed time steps

  • Phasor solution

The Powergui block is necessary for simulation of any Simulink model containing SimPowerSystems™ blocks. It is used to store the equivalent Simulink circuit that represents the state-space equations of the model.

When using this block in a model, you must follow these rules:

  • Place the Powergui block at the top level of diagram for optimal performance. You can place it anywhere inside subsystems for your convenience; its functionality will not be affected.

  • You can have a maximum of one Powergui block per model.

  • You must name the block powergui.

Graphical User Interface Tools

The Powergui block also gives you access to various graphical user interface (GUI) tools and functions for the steady-state analysis of SimPowerSystems models, the analysis of simulation results, and for the design of advanced block parameters.

Dialog Box and Parameters

Simulation and Configuration Options

To specify the simulation type, parameters, and preferences, select Configure parameters in the Powergui dialog box. This selection opens another dialog box with the Powergui block parameters. This dialog box contains three tabs, Solver, Flow, and Preferences.

Solver Tab

The configuration of the Solver tab depends on the option that you select from the Simulation type drop-down list.

Simulation type

Select Continuous to perform a continuous solution of the model.

Select Discrete to perform a discretization of the model. The sample time is specified by the Sample time parameter.

Select Phasor to perform phasor simulation of the model, at the frequency specified by the Phasor frequency parameter.

Enable use of ideal switching devices

If selected, the switches and power electronic blocks are modeled by an alternative method allowing ideal or quazi-ideal switches. For more information, see Using the Ideal Switching Device Method. This parameter is visible only when the Simulation type parameter is set to Continuous.

Disable snubbers in switching devices

If selected, the snubber devices of the power electronic and breaker blocks in your model are disabled and are not modeled. This parameter is visible only if Enable use of ideal switching devices is selected.

Disable On resistance in switching devices (Ron=0)

If selected, the internal resistance Ron of switches and power electronic devices is disabled and forced to zero ohms. This parameter is visible only if Enable use of ideal switching devices is selected.

Disable Forward voltage in switching devices (Vf=0)

If selected, the internal forward voltage Vf of power electronic devices is disabled and forced to zero volts. This parameter is visible only if Enable use of ideal switching devices is selected.

Display circuit differential equations

If selected, differential equations of the model are displayed in the command window when the simulation starts. This parameter is visible only if Enable use of ideal switching devices is selected. For more information, see Using the Ideal Switching Device Method.

Solver type

Set to Tustin to discretize the electrical model using the Tustin method.

Set to Backward Euler to discretize the electrical model using the Backward Euler method.

For more information on what method you should use in your application, see Simulating Discretized Electrical Systems.

Sample time (s)

Specify the sample time used to discretize the electrical circuit. This parameter is visible only when the Simulation type parameter is set to Discrete.

The Sample time parameter must be set to a value greater than 0. The icon displays the value of the sample time.

Phasor frequency (Hz)

Specify the frequency used by the software to perform the phasor simulation of the model. This parameter is visible only when the Simulation type parameter is set to Phasor.

Load Flow Tab

The load flow parameters are used for model initialization only and they have no impact on the simulation's performance.

Load flow frequency (Hz)

Specify the frequency used by the Load Flow tool to compute the normalized Ybus network admittance matrix of the model and to perform the load flow calculations.

Base power Pbase (VA)

Specify the base power used by the Load Flow tool to compute the normalized Ybus network admittance matrix in pu/Pbase and bus base voltages of the model, at the frequency specified by the Load flow frequency parameter.

To avoid a badly conditioned Ybus matrix, select the base power value in the range of nominal powers and loads of the model. For a transmission network with voltages ranging from 120 kV to 765 kV, a 100 MVA base is usually selected. For a distribution network or for a small plant consisting of generators, motors and loads having a nominal power in the range of hundreds of kilowatts, a 1 MVA base power is better adapted.

PQ tolerance (pu)

Defines the tolerance between P and Q when the Load flow tool stops to iterate.

Max iterations

Defines the maximum number of iterations the Load flow tool iterates until the P and Q powers mismatch at each bus is lower than the PQ tolerance parameter value (in pu/Pbase). The power mismatch is defined as the difference between the net power injected into the bus by generators and loads and the power transmitted on all links leaving that bus. For example, if the base power is 100 MVA and PQ tolerance is set to 1e-4, the maximum power mismatch at all buses does not exceed 0.1 MW or 0.1 Mvar.

Voltage units

Determine the voltage units (V, kV) used by the Load Flow tool to display voltages.

Power units

Determine the power units (W, kW, MW) used by the Load Flow tool to display powers.

Preferences Tab

Disable SimPowerSystems warnings

When this check box is selected, the SimPowerSystems warnings are not displayed during the analysis and simulation of the model.

Display SimPowerSystems compilation messages

If selected, the command line echo messages are enabled during the analysis of the model.

Use TLC file when in Accelerator Simulation Mode and for code generation

If selected, TLC state-space S-functions (sfun_spssw_contc.tlc and sfun_spssw_discc.tlc) are used in Accelerator mode and for code generation.

Clear this box if you notice a slowdown in performance when using Accelerator mode, compared to previous releases. This slowdown is observed if you have the LCC compiler installed as the default compiler for building external interface (mex).

Start simulation with initial electrical states from

If blocks is selected, initial state values defined in blocks are used for the simulation.

If steady is selected, force all initial electrical state values to steady-state values.

If zero is selected, force all initial electrical state values to zero.

Restore disabled links of SimPowerSystems blocks

If yes is selected, the Powergui block detects SimPowerSystems blocks that have a disabled link at the simulation start and restores the link automatically.

If warning is selected, the Powergui block detects SimPowerSystems blocks that have a disabled link at the simulation start and displays a warning.

If zero is selected, SimPowerSystems blocks with disabled links are not detected and relinked.

Analysis Tools

Steady-State Voltages and Currents

Open the Steady-State Voltages and Currents Tool dialog box that displays the steady-state voltages and currents of the model. For more information, see the power_steadystate reference page.

Initial States Setting

Open the Initial States Setting Tool dialog box that allows you to display and modify initial capacitor voltages and inductor currents of the model. For more information, see the power_initstates reference page.

Load Flow

Open the Load Flow Tool dialog box to perform load flow and initialize three-phase networks and machines so that the simulation starts in steady state.

The Load Flow tool uses the Newton-Raphson method to provide robust and faster convergence solution compared to the Load Flow and Machine Initialization tool.

The Load Flow tool offers most of the functionality of other tools available in the power utility industry. For more information, see the power_loadflow reference page.

Machine Initialization

Open the Machine Initialization Tool dialog box to initialize three-phase networks containing three-phase machines so that the simulation starts in steady state. The Load Flow and Machine Initialization tool offers simplified load flow features but can still initialize machine initial currents of your models. For more information, see the power_loadflow reference page.

Use LTI Viewer

Open a window to generate the state-space model of your system (if you have Control System Toolbox™ software installed) and automatically open the LTI Viewer interface for time and frequency domain responses. For more information, see the power_ltiview reference page.

Impedance vs Frequency Measurement

Open the Impedance vs Frequency Measurement Tool dialog box to display the impedance versus frequency defined by the Impedance Measurement blocks. For more information, see the power_zmeter reference page.

FFT Analysis

Open the FFT Analysis Tool dialog box to perform Fourier analysis of signals stored in a Structure with Time format. For more information, see the power_fftscope reference page.

An example of using the FFT Analysis tool is described in Performing Harmonic Analysis Using the FFT Tool.

Generate Report

Open the Generate Report Tool dialog box that allow you to generate a report of steady state variables, initial states, and machine load flow for a model. For more information, see the power_report reference page.

Hysteresis Design Tool

Open a window to design a hysteresis characteristic for the saturable core of the Saturable Transformer block and the Three-Phase Transformer blocks (two- and three-windings). For more information, see the power_hysteresis reference page.

Compute RLC Line Parameters

Open a window to compute RLC parameters of an overhead transmission line from its conductor characteristics and tower geometry. For more information, see the power_lineparam reference page.

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