3-phase transformer (Dy)

Three-phase delta–star transformer with a nominal ratio.

  • electrical
  • 3-phase
  • Modelica Standard Library
  • 3 ports
  • 1 parameter
Block3-phase transformer (Dy)KindthreePhaseTransformerLibrary3-phase

Description

A three-phase two-winding transformer with vector group Dy1: delta-connected high-voltage winding, star-connected low-voltage winding with an accessible neutral. The low-voltage side lags the high-voltage side by 30°.

Each winding has a fixed series resistance and leakage inductance; the core is ideal.

Example

Three-phase transformer A Dy1 transformer with ratio 2 steps 100 V phase voltage down into a star-connected load.

100 V 50 HzStar supplyGround supplyStar loadGround loadDy1 transformerGround (neutral)Load 50 ΩOutput voltages
In Gradara, select a 3-phase transformer (Dy) block and press F1, then choose Open example. It opens as a new model in My models, ready to run.

Also in this example:Ground3-phase AC source3-phase resistorStar point3-phase voltage sensor

Ports

Conserving terminals 3

  • HVplug13-phase

    High-voltage three-phase plug (phases a, b, c), delta winding. No neutral.

  • LVplug23-phase

    Low-voltage three-phase plug (phases a, b, c), star winding.

  • Nstarpoint2electrical

    Neutral of the low-voltage star winding (single-phase pin).

Parameters

  • Ration1

    ≥ 0

    Ratio of high-voltage to low-voltage line-to-line voltage. Positive.

Equations

Modelica
No load: line-to-line voltage of plug1 = n · line-to-line voltage of plug2
Fixed per phase: R1 = R2 = 10 mΩ, L1σ = L2σ = 1 mH, at 20 °C

Implementation

Modelica Standard Library 4.1.0Modelica.Electrical.Machines.BasicMachines.Transformers.Dy.Dy01
MSL documentation

Assumptions and limitations

  • Ideal core: no magnetizing current, core loss, saturation, or inrush.
  • The winding resistances and leakage inductances are not adjustable. At 50 Hz, 1 mH is about 0.31 Ω per winding, which is large for low-voltage, high-current use.

Tips

  • Ground starpoint2 to reference the low-voltage side; the delta side has no ground path of its own.

See also

Select a block in Gradara and press F1 to open its page offline.