Power

(To be removed) Compute active and reactive powers of voltage-current pair at fundamental frequency

The Specialized Power Systems library will be removed in R2026a. Use the Simscape™ Electrical™ blocks and functions instead. For more information on updating your models, see Upgrade Specialized Power System Models to use Simscape Electrical Blocks.

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Libraries:
Simscape / Electrical / Specialized Power Systems / Sensors and Measurements

Description

The Power block computes the active power (P), in watts, and the reactive power (Q), in vars, of a voltage-current pair at fundamental frequency. To perform this computation, the block first determines the fundamental values (magnitude and phase) of the two input signals V & I. The following P and Q are then calculated:

$$\begin{array}{l}P=\frac{\left|V\right|}{\sqrt{2}}\times \frac{\left|I\right|}{\sqrt{2}}\times \cos (\phi )\\ Q=\frac{\left|V\right|}{\sqrt{2}}\times \frac{\left|I\right|}{\sqrt{2}}\times \sin (\phi )\\ \phi =\angle V-\angle I\end{array}$$

As this block uses a running average window, one cycle of simulation must complete before the outputs give the correct value. For the first cycle of simulation, the outputs are held constant using the values specified by the Voltage initial input and Current initial input parameters.

Characteristics

Sample Time	Specified in the Sample Time parameter Continuous if Sample Time = 0
Scalar Expansion	Yes, of the parameters
Dimensionalized	Yes

Ports

Input

V — Voltage signal

scalar

The voltage signal.

I — Current signal

scalar

The current signal.

Output

P — Active power

scalar

The active power of voltage-current pair signal, in watts.

Q — Reactive power

scalar

The reactive power of voltage-current pair signal, in vars.

Parameters

Fundamental frequency (Hz) — Input signal fundamental frequency

60 (default) | positive scalar

Specify the fundamental frequency, in hertz, of the input signals.

Voltage initial input [ Mag, Phase (degrees) ] — Initial voltage magnitude and phase

[1, 0] (default) | two-element vector

Specify the voltage initial magnitude and phase to set a constant output for the first cycle of simulation.

Current initial input [ Mag, Phase (degrees) ] — Initial current magnitude and phase

[1, 0] (default) | two-element vector

Specify the current initial magnitude and phase to set a constant output for the first cycle of simulation.

Sample time — Block sample time

0 (default) | nonnegative scalar

Specify the sample time of the block, in seconds. Set to 0 to implement a continuous block.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2013a