# Three-Phase V-I Measurement

Measure three-phase currents and voltages in circuit

**Library:**Simscape / Electrical / Specialized Power Systems / Sensors and Measurements

## Description

The Three-Phase V-I Measurement block is used to measure instantaneous three-phase voltages and currents in a circuit. When connected in series with three-phase elements, it returns the three phase-to-ground or phase-to-phase peak voltages and currents.

The block can output the voltages and currents in per unit (pu) values or in volts and amperes.

If you choose to measure phase-to-ground voltages in per unit, the block converts the measured voltages based on peak value of nominal phase-to-ground voltage:

$${V}_{\text{abc}}\left(pu\right)=\frac{{V}_{\text{phasetoground}}\left(V\right)}{{V}_{\text{base}}\left(V\right)}$$

where

$${V}_{\text{base}}=\frac{{V}_{\text{nom}}\left(Vrms\right)}{\sqrt{3}}\cdot \sqrt{2}$$

If you choose to measure phase-to-phase voltages in per unit, the block converts the measured voltages based on peak value of nominal phase-to-phase voltage:

$${V}_{\text{abc}}\left(pu\right)=\frac{{V}_{\text{phasetophase}}\left(V\right)}{{V}_{\text{base}}\left(V\right)}$$

where

$${V}_{\text{base}}={V}_{\text{nom}}\left(Vrms\right)\cdot \sqrt{2}$$

If you choose to measure currents in per unit, the block converts the measured currents based on the peak value of the nominal current:

$${I}_{\text{abc}}\left(pu\right)=\frac{{I}_{\text{abc}}\left(A\right)}{{I}_{\text{base}}\left(A\right)}$$

where

$$I\text{base}=\frac{{P}_{\text{base}}}{{V}_{\text{nom}}}\ast \frac{\text{sqrt}(2)}{\text{sqrt}(3)}$$

V_{nom} and P_{base} are specified in the
Three-Phase V-I Measurement block dialog box.

The steady-state voltage and current phasors measured by the Three-Phase V-I Measurement
block can be obtained from the Powergui block by selecting **Steady-State
Voltages and Current**s. The phasor magnitudes displayed in the
Powergui stay in peak or RMS values even if the output signals are converted to
pu.

## Ports

### Output

### Conserving

## Parameters

## Model Examples

## Extended Capabilities

## Version History

**Introduced before R2006a**