Two windings transformer

The com.powsybl.iidm.network.TwoWindingsTransformer interface is used to model a two windings power transformer. A two windings power transformer is connected to two voltage levels (side 1 and side 2) that belong to a same substation. A ratio tap changer and/or a phase tap changer can be associated with a two windings power transformer.

Characteristics

Attribute Type Unit Required Default value Description
id string - yes - Unique identifier of the transformer
name string - yes - Human-readable name of the transformer
$r_{nom}$ double $\Omega$ yes - The nominal series resistance at the side 2 of the transformer
$x_{nom}$ double $\Omega$ yes - The nominal series reactance at the side 2 of the transformer
$g_{nom}$ double S yes - The nominal magnetizing conductance at the side 2 of the transformer
$b_{nom}$ double S yes - The nominal magnetizing susceptance at the side 2 of the transformer
$V_{1\ nom}$ double kV yes - The rated voltage at side 1
$V_{2\ nom}$ double kV yes - The rated voltage at side 2

Two windings transformers can also have current limits defined for each end.

Model

Two windings transformer are modeled with the following equivalent $\pi$ model:

With the series impedance $z$ and the shunt admittance $y$ and the voltage ratio $\rho$ and the angle difference $\alpha$ and potentially parameters from the current step of a ratio tap changer and/or a phase tap changer, we have:

Using the above notation, the equations of the two windings transformer, in complex notations, are as follow:

Examples

This example shows how to create a two windings transformer in the network:

TwoWindingsTransformer twoWindingsTransformer = substation.newTwoWindingsTransformer()
.setId("TWT2")
.setName("My two windings transformer")
.setVoltageLevel1("VL1")
.setVoltageLevel2("VL2")
.setNode1(1)
.setNode2(2)
.setR(0.5)
.setX(4)
.setG(0)
.setB(0)
.setRatedU1(24)
.setRatedU2(385)