Modelica.Electrical.Machines.BasicMachines.Transformers

Library for technical 3phase transformers

Information

This package contains components to model technical threephase transformers:

Transformer: transformer model to choose connection / vector group
Yy: Transformers with primary primary Y / secondary y
Yd: Transformers with primary primary Y / secondary d
Yz: Transformers with primary primary Y / secondary zig-zag
Dy: Transformers with primary primary D / secondary y
Dd: Transformers with primary D / secondary d
Dz: Transformers with primary D / secondary zig-zag

Transformers are modeled by an ideal transformer, adding primary and secondary winding resistances and stray inductances.
All transformers extend from the base model PartialTransformer, adding the primary and secondary connection.
VectorGroup defines the phase shift between primary and secondary voltages, expressed by a number phase shift/30 degree (i.e. the hour on a clock face). Therefore each transformer is identified by two characters and a two-digit number, e.g. Yd11 ... primary connection Y (star), secondfary connection d (delta), vector group 11 (phase shift 330 degree)
With the "supermodel" Tranformer the user may choose primary and secondary connection as well as the vector group.
It calculates winding ratio as well as primary and secondary winding resistances and stray inductances, distributing them equally to primary and secondary winding, from the following parameters:

nominal frequency
primary voltage (RMS line-to-line)
secondary voltage (RMS line-to-line)
nominal apparent power
impedance voltage drop
short-circuit copper losses

The impedance voltage drop indicates the (absolute value of the) voltage drop at nominal load (current) as well as the voltage we have to apply to the primary winding to achieve nominal current in the short-circuited secondary winding.

Please pay attention to proper grounding of the primary and secondary part of the whole circuit.
The primary and secondary starpoint are available as connectors, if the connection is not delta (D or d).
In some cases (Yy or Yz) it may be necessary to ground one of the transformer's starpoints even though the source's and/or load's starpoint are grounded; you may use a reasonable high earthing resistance.

Limitations and assumptions:

number of phases is limited to 3, therefore definition as a constant m=3
symmetry of the 3 phases resp. limbs
temperature dependency is neglected, i.e. resistances are constant
saturation is neglected, i.e. inductances are constant
magnetizing current is neglected
magnetizing losses are neglected
additional (stray) losses are neglected

Further development:

modeling magnetizing current, including saturation
temperature dependency of winding resistances

Main Authors:: Anton Haumer
Technical Consulting & Electrical Engineering
A-3423 St.Andrae-Woerdern
Austria
email: a.haumer@haumer.at

The Modelica package is free software; it can be redistributed and/or modified under the terms of the Modelica license, see the license conditions and the accompanying disclaimer here.

Extends from Modelica.Icons.Library2 (Icon for library where additional icon elements shall be added).

Package Content

Name Description

Yy Transformers: primary Y / secondary y

Yd Transformers: primary Y / secondary d

Yz Transformers: primary Y / secondary zig-zag

Dy Transformers: primary D / secondary y

Dd Transformers: primary D / secondary d

Dz Transformers: primary D / secondary ziag-zag

Name	Description
Yy	Transformers: primary Y / secondary y
Yd	Transformers: primary Y / secondary d
Yz	Transformers: primary Y / secondary zig-zag
Dy	Transformers: primary D / secondary y
Dd	Transformers: primary D / secondary d
Dz	Transformers: primary D / secondary ziag-zag

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