# RLC (Three-Phase)

Three-phase impedance

Libraries:
Simscape / Electrical / Passive / RLC Assemblies

## Description

The RLC (Three-Phase) block models a three-phase impedance with two three-phase connections. Each of the three identical impedance components can include any combination of a resistor (R), capacitor (C), and inductor (L), connected in series or in parallel.

Define the values for the R, L, and C components by specifying the appropriate block parameters. Do not set the parameter values to zero or infinity to remove terms. Instead, select the correct option for the Component structure parameter.

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.

### Faults

Since R2024b

To model a fault in the RLC (Three-Phase) 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 RLC (Three-Phase) block allows you to represent one or more faulted phases. The block models the faulted phase as a resistor. To specify the value of the faulted resistance, use the Faulted resistance parameter.

For example, this diagram shows the equivalent circuit of three-phase inductor branch.

When you add a branch fault and you set the Faulted phase parameter to `Phase a`, this diagram shows the equivalent circuit of the faulted three-phase inductor branch.

### 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 do not set the Component structure parameter to `R`.

## Ports

### Conserving

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Composite three-phase port.

#### Dependencies

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

Composite three-phase port.

#### Dependencies

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

Electrical conserving port associated with the a-phase.

#### Dependencies

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

Electrical conserving port associated with the b-phase.

#### Dependencies

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

Electrical conserving port associated with the c-phase.

#### Dependencies

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

Electrical conserving port associated with the a-phase.

#### Dependencies

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

Electrical conserving port associated with the b-phase.

#### Dependencies

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

Electrical conserving port associated with the c-phase.

#### Dependencies

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

## Parameters

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### Main

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.

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

Resistance of each of the line impedances.

#### Dependencies

To enable this parameter, set Component structure to either `R`, `Series RL`, ```Series RC```, `Series RLC`, `Parallel RL`, or ```Parallel RC```.

Inductance of each of the line impedances.

#### Dependencies

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

Capacitance in each of the line impedances.

#### Dependencies

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

### Parasitics

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```.

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```.

### 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.

Since R2024b

Option to add a branch fault in the RLC (Three-Phase) block.

Since R2024b

Option to specify the faulted phase of the RLC (Three-Phase) block. You can specify one or more faulted phases.

#### Dependencies

To enable this parameter, add a fault to the RLC (Three-Phase) block by clicking the Add fault hyperlink in the Branch fault parameter.

Since R2024b

Resistance of the faulted impedance components.

#### Dependencies

To enable this parameter, add a fault to the RLC (Three-Phase) block by clicking the Add fault hyperlink in the Branch fault parameter.

## Version History

Introduced in R2013b

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