# Sequence Analyzer (Phasor)

Compute sequence components (positive, negative, and zero) of three-phase phasor signal

## Library

Simscape / Electrical / Specialized Power Systems / Control & Measurements / Measurements

Simscape / Electrical / Specialized Power Systems / Fundamental Blocks / Measurements / Additional Measurements

• ## Description

The Sequence Analyzer (Phasor) block computes the three-sequence phasor components (positive sequence u1, negative sequence u2, and zero sequence u0) of a three-phase phasor signal as follows:

`$\left[\begin{array}{c}{u}_{1}\\ {u}_{2}\\ {u}_{0}\end{array}\right]=\frac{1}{3}\left[\begin{array}{ccc}1& a& {a}^{2}\\ 1& {a}^{2}& a\\ 1& 1& 1\end{array}\right]\left[\begin{array}{c}{u}_{a}\\ {u}_{b}\\ {u}_{c}\end{array}\right]$`

where $\alpha$ is the complex operator performing a 2$\pi /3$ rotation:

`$a={e}^{\frac{j2\pi }{3}}$`

## Parameters

Sequence

Select the sequence components: `Positive` (default), `Negative`, `Zero`, or all three sequences `Positive Negative Zero`.

## Inputs and Outputs

`abc`

The three-phase phasor signal [ua ub uc].

`mag u`

Returns the magnitude of the selected sequence phasor component.

`angle u`

Returns the angle, in degrees, of the selected sequence phasor component.

## Characteristics

 Direct Feedthrough Yes Dimensionalized No

## Examples

The `power_PhasorMeasurements` example shows the use of the Sequence Analyzer (Phasor) block.