Three windings transformer

The com.powsybl.iidm.network.ThreeWindingsTransformer interface is used to model a three windings power transformer. A three windings power transformer is connected to three voltage levels (side 1, side 2 and side 3) that belong to the same substation:

• Side 1 is the primary side (high voltage)
• Side 2 and Side 3 can indifferently be the secondary side (medium voltage) or the tertiary side (low voltage) A Ratio Tap Changer can be associated to the side 2 or the side 3 of a three windings power transformer.

# Characteristics

Attribute Type Required Default value Description
Leg1 ThreeWindingsTransformer.Leg1 yes - The leg at the primary side
Leg2 ThreeWindingsTransformer.Leg2or3 yes - The leg at the secondary side
Leg3 ThreeWindingsTransformer.Leg2or3 yes - The leg at the tertiary side

Three windings transformers can also have current limits defined for each leg.

## Leg1

ThreeWindingsTransformer.Leg1 is a nested interface used to model the primary side of a three windings power transformer.

### Characteristics

Attribute Type Unit Required Default value Description
Terminal Terminal - yes - The terminal the leg is connected to
R double $\Omega\$ yes - The nominal series resistance specified at the voltage of the leg
X double $\Omega\$ yes - The nominal series reactance specified at the voltage of the leg
G double S yes - The nominal magnetizing conductance specified at the voltage of the leg
B double S yes - The nominal magnetizing susceptance specified at the voltage of the leg
RatedU double kV yes - The rated voltage

## Leg2or3

ThreeWindingsTransformer.Leg2or3 is a nested interface used to model the secondary or the tertiary side of a three windings power transformer.

### Characteristics

Attribute Type Unit Required Default value Description
Terminal Terminal - yes - The terminal the leg is connected to
R double $\Omega\$ yes - The nominal series resistance specified at the voltage of the leg
X double $\Omega\$ yes - The nominal series reactance specified at the voltage of the leg
RatedU double kV yes - The rated voltage

# Examples

This is an example of how to create a new ThreeWindingsTransformer in the network:

ThreeWindingsTransformer threeWindingsTransformer = substation.newThreeWindingsTransformer()
.setId("TWT3")
.newLeg1()
.setVoltageLevel("VL1")
.setNode(11)
.setR(17.424)
.setX(1.7424)
.setG(0.00573921028466483)
.setB(0.000573921028466483)
.setRatedU(132.0)
.newLeg2()
.setVoltageLevel("VL2")
.setNode(22)
.setR(1.089)
.setX(0.1089)
.setRatedU(33.0)