Wye-Connected Variable Load

Three-phase variable load wired in wye configuration

• 

Libraries:
Simscape / Electrical / Passive / RLC Assemblies

Description

The Wye-Connected Variable Load block models a three-phase variable load wired in a wye configuration. Each limb of the load contains a resistor. The block calculates the resistance required to draw the real power of the physical signal input P at the rated voltage that you specify. Therefore, the block can represent a real load.

To ensure that the resistance is always greater than zero, you specify the minimum real power that the load consumes. The minimum real power must be greater than zero.

Equations

This equation defines the resistance,

$$R=\frac{V_{Rated}^2}{P},$$

where:

• R is the per-phase series resistance.

• V_Rated is the RMS, rated line-line voltage.

• P is the three-phase real power required.

Ports

Input

P — Real power

physical signal

Physical signal input port associated with the real power.

Conserving

~ — Composite three-phase port

electrical

Electrical conserving port representing the three phases of the three-phase block. For more information, see Three-Phase Ports.

Dependencies

To enable this port, set the Electrical connection parameter to Composite three-phase ports.

a — Phase a of three-phase system

electrical

Electrical conserving port associated with the phase a of the three-phase block.

Dependencies

To enable this port, set the Electrical connection parameter to Expanded three-phase ports.

b — Phase b of three-phase system

electrical

Electrical conserving port associated with the phase b of the three-phase block.

Dependencies

To enable this port, set the Electrical connection parameter to Expanded three-phase ports.

c — Phase c of three-phase system

electrical

Electrical conserving port associated with the phase c of the three-phase block.

Dependencies

To enable this port, set the Electrical connection parameter to Expanded three-phase ports.

n — Neutral phase

electrical

Electrical conserving port associated with the neutral phase.

Parameters

Electrical connection — Whether to model composite or expanded three-phase ports

Composite three-phase ports (default) | Expanded three-phase ports

Since R2026a

Whether to model composite or expanded three-phase ports.

Composite three-phase ports represent three individual electrical conserving ports with a single block port. You can use composite three-phase ports to build models that correspond to single-line diagrams of three-phase electrical systems.

Expanded three-phase ports represent the individual phases of a three-phase system using three separate electrical conserving ports.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

Parameter:	port_option
Values:	"ee.enum.threePhasePort.composite" (default) | "ee.enum.threePhasePort.expanded"

Rated voltage — Rated line-line voltage

24e3 V (default)

RMS, rated line-line voltage for the resistance equation.

Minimum real power — Minimum real power

1e3 W (default) | positive scalar

Minimum real power that the three-phase load dissipates when supplied at the rated voltage. The value must be greater than 0.

Extended Capabilities

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

Version History

Introduced in R2014b

R2026a: The Modeling option parameter has changed

The Modeling option parameter has been replaced with the Electrical connection parameter. You can now also set this parameter value programmatically by using the set_param function.

If you created a model containing this block in an earlier release, the software now automatically sets the value of the Electrical connection parameter to the previous value of the Modeling option parameter.