Wye-Connected Load

Three-phase load wired in wye configuration

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Libraries:
Simscape / Electrical / Passive / RLC Assemblies

Description

The Wye-Connected Load block models a three-phase load wired in a wye configuration. Each limb of the load can include any combination of a resistor (R), capacitor (C), and inductor (L), connected in series or in parallel.

You can specify values for the R, L, and C components directly in terms of resistance, inductance, and capacitance, or by rated powers at a rated voltage and frequency.

• If you parameterize the block directly in terms or R, L, and C values, then for initialization, provide a three-element row vector of initial voltages for a capacitor, and a three-element row vector of initial currents for an inductor.

• If you parameterize the block in terms of rated powers, then specify initial conditions in terms of an initial voltage, initial voltage phase, and initial frequency. For example, if the load is connected directly to a three-phase voltage source, then the initial conditions are identical to the source values for RMS line voltage, frequency, and phase shift. To specify zero initial-voltage magnitude, set the initial voltage to 0.

For certain combinations of R, L, and C, for some circuit topologies, you should specify parasitic resistance or conductance values that help the simulation to converge numerically. These parasitic terms help create a small parallel resistive path for an inductor and a small series resistance for a capacitor. When you parameterize the block in terms of rated powers, the rated power values do not account for these small parasitic terms. The rated powers represent only the R, L, and C values of the load itself.

Block Parameterization

These tables list the block parameters for each value of the Component structure parameter, based on the Parameterization option you select:

• Specify by rated power and voltage

• Specify component values directly

Specify by Rated Power and Voltage

Component Structure	Main Parameters	Parasitics Parameters	Initial Conditions Parameters
R	Rated voltage Real power	None	None
L	Rated voltage Rated electrical frequency Inductive reactive power	Parasitic parallel conductance	Terminal voltage magnitude Terminal voltage angle Frequency
C	Rated voltage Rated electrical frequency Capacitive reactive power	Parasitic series resistance	Terminal voltage magnitude Terminal voltage angle Frequency
Series RL	Rated voltage Rated electrical frequency Real power Inductive reactive power	Parasitic parallel conductance	Terminal voltage magnitude Terminal voltage angle Frequency
Series RC	Rated voltage Rated electrical frequency Real power Capacitive reactive power	None	Terminal voltage magnitude Terminal voltage angle Frequency
Series LC	Rated voltage Rated electrical frequency Inductive reactive power Capacitive reactive power	Parasitic parallel conductance	Terminal voltage magnitude Terminal voltage angle Frequency
Series RLC	Rated voltage Rated electrical frequency Real power Inductive reactive power Capacitive reactive power	Parasitic parallel conductance	Terminal voltage magnitude Terminal voltage angle Frequency
Parallel RL	Rated voltage Rated electrical frequency Real power Inductive reactive power	None	Terminal voltage magnitude Terminal voltage angle Frequency
Parallel RC	Rated voltage Rated electrical frequency Real power Capacitive reactive power	Parasitic series resistance	Terminal voltage magnitude Terminal voltage angle Frequency
Parallel LC	Rated voltage Rated electrical frequency Inductive reactive power Capacitive reactive power	Parasitic series resistance	Terminal voltage magnitude Terminal voltage angle Frequency
Parallel RLC	Rated voltage Rated electrical frequency Real power Inductive reactive power Capacitive reactive power	Parasitic series resistance	Terminal voltage magnitude Terminal voltage angle Frequency

Specify Component Values Directly

Component Structure	Main Parameters	Parasitics Parameters	Initial Targets Variables
R	Resistance	None	None
L	Inductance	Parasitic parallel conductance	Initial inductor current [ Ia Ib Ic ]
C	Capacitance	Parasitic series resistance	Initial capacitor voltage [ Va Vb Vc ]
Series RL	Resistance Inductance	Parasitic parallel conductance	Initial inductor current [ Ia Ib Ic ]
Series RC	Resistance Capacitance	None	Initial capacitor voltage [ Va Vb Vc ]
Series LC	Inductance Capacitance	Parasitic parallel conductance	Initial inductor current [ Ia Ib Ic ] Initial capacitor voltage [ Va Vb Vc ]
Series RLC	Resistance Inductance Capacitance	Parasitic parallel conductance	Initial inductor current [ Ia Ib Ic ] Initial capacitor voltage [ Va Vb Vc ]
Parallel RL	Resistance Inductance	None	Initial inductor current [ Ia Ib Ic ]
Parallel RC	Resistance Capacitance	Parasitic series resistance	Initial capacitor voltage [ Va Vb Vc ]
Parallel LC	Inductance Capacitance	Parasitic series resistance	Initial inductor current [ Ia Ib Ic ] Initial capacitor voltage [ Va Vb Vc ]
Parallel RLC	Resistance Inductance Capacitance	Parasitic series resistance	Initial inductor current [ Ia Ib Ic ] Initial capacitor voltage [ Va Vb Vc ]

Faults

Since R2024b

To model a fault in the Wye-Connected Load block, in the Faults section, click the Add fault hyperlink next to the fault that you want to model. In the Add Fault window, specify the fault properties. For more information about fault modeling, see Fault Behavior Modeling and Fault Triggering.

The Wye-Connected Load block allows you to model these types of fault at the three-phase connection port:

• Single-phase-to-ground fault (a-g, b-g, or c-g)

• Two-phase fault (a-b, b-c, or c-a)

• Two-phase-to-ground fault (a-b-g, b-c-g, or c-a-g)

• Three-phase fault (a-b-c)

• Three-phase-to-ground fault (a-b-c-g)

Variables

To set the priority and initial target values for the block variables prior to simulation, use the Initial Targets section in the block dialog box or Property Inspector. For more information, see Set Priority and Initial Target for Block Variables.

Nominal values provide a way to specify the expected magnitude of a variable in a model. Using system scaling based on nominal values increases the simulation robustness. Nominal values can come from different sources, one of which is the Nominal Values section in the block dialog box or Property Inspector. For more information, see System Scaling by Nominal Values.

For this block, the Initial Targets and Nominal Values settings are visible only if, in the Main section, you set the Parameterization parameter to Specify component values directly and you do not set the Component structure parameter to R.

Examples

Three-Phase Synchronous Machine Control

Control and initialize a Synchronous Machine (SM). The test circuit shows the SM operating as a generator. The terminal voltage is controlled using an AVR and the speed is controlled using a governor.

• Open Model

Three-Phase Asynchronous Wind Turbine Generator

Model an induction machine used as a wind turbine generator.

• Open Model

Ports

Conserving

~ — Three-phase port

electrical

Composite three-phase port.

For more information about composite and expanded three-phase ports, see Three-Phase Ports.

Dependencies

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

a — a-phase

electrical

Electrical conserving port associated with the a-phase.

Dependencies

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

b — b-phase

electrical

Electrical conserving port associated with the b-phase.

Dependencies

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

c — c-phase

electrical

Electrical conserving port associated with the c-phase.

Dependencies

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

n — Neutral phase

electrical

Electrical conserving port associated with the neutral phase.

Parameters

Main

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

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

Since R2024b

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.

Parameterization — Parameterization

Specify by rated power and voltage (default) | Specify component values directly

Select how to specify values for the R, L, and C components:

• Specify by rated power and voltage — Specify values for the R, L, and C components by rated powers at a rated voltage and frequency. This option is the default.

• Specify component values directly — Specify values for the R, L, and C components directly in terms of resistance, inductance, and capacitance.

Switching the Parameterization value resets the Component structure value. Select the component parameterization option first, and then the component structure. If you later switch the Parameterization value, check the Component structure value and reselect it, if necessary.

Component structure — Desired component combination

R (default) | L | C | Series RL | Series RC | Series LC | Series RLC | Parallel RL | Parallel RC | Parallel LC | Parallel RLC

Select the desired combination of a resistor (R), capacitor (C), and inductor (L), connected in series or in parallel.

Rated voltage — Rated voltage

24e3 V (default) | nonnegative scalar

Voltage for which load powers are specified.

Dependencies

To enable this parameter, set Parameterization to Specify by rated power and voltage.

Real power — Total real dissipated power

1e3 W (default) | positive scalar

Total real power dissipated by three-phase load when supplied at the rated voltage.

Dependencies

To enable this parameter, set Parameterization to Specify by rated power and voltage and Component structure to either R, Series RL, Series RC, Series RLC, Parallel RL, or Parallel RC.

Rated electrical frequency — Rated electrical frequency

60 Hz (default) | positive scalar

Frequency for which you specify the reactive load powers.

Dependencies

To enable this parameter, set Parameterization to Specify by rated power and voltage.

Inductive reactive power — Inductive reactive power

1e2 A*V (default) | positive scalar

Total inductive reactive power that the three-phase load takes when supplied at the rated voltage.

Dependencies

To enable this parameter, set Parameterization to Specify by rated power and voltage and Component structure to either L, Series RL, Series LC, Series RLC, Parallel RL, or Parallel LC.

Capacitive reactive power — Total capacitive reactive power

-1e2 A*V (default) | negative scalar

Total capacitive reactive power that the three-phase load takes when supplied at the rated voltage.

Dependencies

To enable this parameter, set Parameterization to Specify by rated power and voltage and Component structure to either C, Series RC, Series LC, Series RLC, Parallel RC, or Parallel LC.

Resistance — Resistance

1 Ohm (default) | positive scalar

Resistance of each of the load limbs.

Dependencies

To enable this parameter, set Parameterization to Specify component values and Component structure to either R, Series RL, Series RC, Series RLC, Parallel RL, or Parallel RC.

Inductance — Inductance

0.001 H (default) | positive scalar

Inductance of each of the load limbs.

Dependencies

To enable this parameter, set Parameterization to Specify component values and Component structure to either L, Series RL, Series LC, Series RLC, Parallel RL, or Parallel LC.

Capacitance — Capacitance

1e-6 F (default) | positive scalar

Capacitance in each of the load limbs.

Dependencies

To enable this parameter, set Parameterization to Specify component values and Component structure to either C, Series RC, Series LC, Series RLC, Parallel RC, or Parallel LC.

Parasitics

Parasitic series resistance — Parasitic series resistance

1e-6 Ohm (default) | nonnegative scalar

Series resistance value added to all instances of capacitors in the load.

Dependencies

To enable this parameter, set Component structure to either C, Parallel RC, or Parallel LC.

Parasitic parallel conductance — Parasitic parallel conductance

0 1/Ohm (default) | nonnegative scalar

Parallel conductance value added across all instances of inductors in the load. This parameter represents small parasitic effects.

If you set Component structure to either Series RL, Series LC, or Series RLC, the parasitic parallel conductance is connected across the full branch of the block.

Dependencies

To enable this parameter, set Component structure to either L, Series RL, Series LC, or Series RLC.

Initial Conditions

Terminal voltage magnitude — Magnitude of terminal voltage

24e3 V (default) | nonnegative scalar

Magnitude of the terminal voltage.

Dependencies

To enable this parameter, set Component structure to either L, C, Series RL, Series RC, Series LC, Series RLC, Parallel RL, Parallel RC, or Parallel LC.

Terminal voltage angle — Angle of terminal voltage

0 deg (default) | scalar

Angle of the terminal voltage.

Dependencies

To enable this parameter, set Component structure to either L, C, Series RL, Series RC, Series LC, Series RLC, Parallel RL, Parallel RC, or Parallel LC.

Frequency — Frequency

60 Hz (default) | positive scalar

Frequency.

Dependencies

To enable this parameter, set Component structure to either L, C, Series RL, Series RC, Series LC, Series RLC, Parallel RL, Parallel RC, or Parallel LC.

Faults

To modify the faults, create a fault and, in the block dialog box, click Open fault properties. To open the faults, in the Property Inspector, click the Fault behavior link.

Connection fault — Option to add fault to connection port

Add fault

Since R2024b

Option to add a fault to the three-phase connection port of the load.

To add a fault, click the Add fault hyperlink.

Fault type — Type of fault

Single-phase to ground (a-g) (default) | Single-phase to ground (b-g) | Single-phase to ground (c-g) | Two-phase (a-b) | Two-phase (b-c) | Two-phase (c-a) | Two-phase to ground (a-b-g) | Two-phase to ground (b-c-g) | Two-phase to ground (c-a-g) | Three-phase (a-b-c) | Three-phase to ground (a-b-c-g)

Since R2024b

Type of fault to model. The visibility of the related parameters depends on the fault model.

Dependencies

To enable this parameter, add a fault to the block by clicking the Add fault hyperlink next to the Connection fault parameter.

Faulted phase-neutral resistance — Faulted resistance between phase connection and neutral point

1e-3 Ohm (default) | positive scalar

Since R2024b

Resistance between the phase connection and the neutral point when the fault is active.

Dependencies

To enable this parameter, add a fault to the block by clicking the Add fault hyperlink next to the Connection fault parameter, and set the Fault type parameter to one of these options:

• Single-phase to ground (a-g)

• Single-phase to ground (b-g)

• Single-phase to ground (c-g)

• Two-phase (a-b)

• Two-phase (b-c)

• Two-phase (c-a)

• Two-phase to ground (a-b-g)

• Two-phase to ground (b-c-g)

• Two-phase to ground (c-a-g)

• Three-phase (a-b-c)

• Three-phase to ground (a-b-c-g)

Faulted neutral-ground resistance — Faulted resistance between neutral point and electrical reference

1e-3 Ohm (default) | positive scalar

Since R2024b

Resistance between the neutral point and the electrical reference when fault is active.

Dependencies

To enable this parameter, add a fault to the block by clicking the Add fault hyperlink next to the Connection fault parameter, and set the Fault type parameter to one of these options:

• Single-phase to ground (a-g)

• Single-phase to ground (b-g)

• Single-phase to ground (c-g)

• Two-phase to ground (a-b-g)

• Two-phase to ground (b-c-g)

• Two-phase to ground (c-a-g)

• Three-phase to ground (a-b-c-g)

Unfaulted phase-neutral conductance — Unfaulted conductance between phase connection and neutral point

1e-6 1/Ohm (default) | positive scalar

Since R2024b

Conductance between the phase connection and the neutral point when the fault is not active.

Dependencies

To enable this parameter, add a fault to the block by clicking the Add fault hyperlink next to the Connection fault parameter, and set the Fault type parameter to one of these options:

• Single-phase to ground (a-g)

• Single-phase to ground (b-g)

• Single-phase to ground (c-g)

• Two-phase (a-b)

• Two-phase (b-c)

• Two-phase (c-a)

• Two-phase to ground (a-b-g)

• Two-phase to ground (b-c-g)

• Two-phase to ground (c-a-g)

• Three-phase (a-b-c)

• Three-phase to ground (a-b-c-g)

Extended Capabilities

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

Version History

Introduced in R2013b

R2024b: Model faults at the three-phase connection port

You can now model a phase-to-ground or a phase-to-phase fault at the three-phase connection port of the load. To specify the value of the faulted resistances and the unfaulted conductance, use the Faulted phase-neutral resistance, Faulted neutral-ground resistance, and Unfaulted phase-neutral conductance parameters.

R2024b: The Modeling Option parameter has changed

The Modeling option parameter has been replaced with the Electrical connection parameter inside the Main section in the block dialog box or Property Inspector.

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