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Multimeter

Measure voltages and currents specified in dialog boxes of SimPowerSystems blocks

Library

Measurements

Description

This block measures the voltages and currents specified in the Measurements parameter of SimPowerSystems™ blocks in your model. Choosing voltages or currents through the Multimeter block is equivalent to connecting an internal voltage or current measurement block inside your blocks.

Polarity of Measured Voltages and Currents

The polarity of the measured voltages and current is determined by the + and - terminals of the measured SimPowerSystems blocks. The following table identifies the positive terminals of the SimPowerSystems blocks that do not have the + sign to identify block polarity.

Block

Positive terminal(s)

Mutual Inductance

Three-Phase Mutual Inductance Z1-Z0

1 2 3

ABC

Three-Phase Series RLC Branch

Three-Phase Parallel RLC Branch

ABC

ABC

Three-Phase Breaker

ABC

Breaker

1

For three-phase transformers, the voltage polarities and positive current directions are indicated by the signal labels used in the Multimeter block. For example, Uan_w2 = phase A-to-neutral voltage of the Y connected winding #2 and Iab_w1 = winding current flowing from A to B in the delta-connected winding #1.

Dialog Box and Parameters

Available Measurements

The Available Measurements list box shows the measurements in the Multimeter block. Use the >> button to select measurements from the Available Measurements list box. Click the Update button to refresh the list of available measurements.

The measurements in the list box are identified by the name of the block where the measurement is done. The type of measurement (voltage measurement, current measurement, or flux) is defined by a label preceding the block name. For more information, see the Measurements parameter description in the Dialog Box and Parameters section of blocks in your model.

Selected Measurements

The Selected Measurements list box shows the measurements sent to the output of the block. You can reorder the measurements by using the Up, Down, and Remove buttons. The +/– button allows you to reverse the polarity of any selected measurement.

Plot selected measurements

If selected, displays a plot of selected measurements in a MATLAB® figure window. The plot is generated when the simulation stops.

Output type

Specifies the format of the output signals when the block is used in a phasor simulation. The Output signal parameter is disabled when the block is not used in a phasor simulation. The phasor simulation is activated by a Powergui block placed in the model.

Set to Complex to output the selected measurements as complex values. The outputs are complex signals.

Set to Real-Imag to output the real and imaginary parts of the measurements. For each selected measurement, the multimeter outputs the real and imaginary parts.

Set to Magnitude-Angle to output the magnitude and angle of the selected measurements. For each selected measurement, the multimeter outputs the magnitude and angle values.

Set to Magnitude to output the magnitude of the selected measurements.

Example

The power_compensatedpower_compensated example uses a Multimeter block to measure the voltage across the secondary winding of a Saturable Transformer block and the currents flowing through two Series RLC Load blocks.

Drag a Multimeter block into the model. In the dialog box of the 250 MVA block, set the Measurements parameter to All measurements (V,I,flux). In the 110 Mvar block, set the parameter to Branch voltage and in the 110 Mvar1 block, set it to Branch voltage and current.

The output of the Multimeter block is connected to a Scope block in order to display the measurements during the simulation. In addition, you can select the Plot selected measurements parameter to display a plot of selected measurements when simulation stops.

Open the Multimeter block dialog box and select the signals you want to observe, as described in the Dialog Box and Parameters section. Notice the labels used to define the available measurements in the Multimeter block. For a description of these labels, see the reference section of the Saturable Transformer block and Series RLC Load block.

Start the simulation. After 0.4 seconds, the simulation stops and a MATLAB figure window opens to display the selected measurements in the Multimeter block.

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