Siemens Transformer Technology Seminar Stray Flux …w3.usa.siemens.com/smartgrid/us/en/events/Documents/Transformer... · Siemens Transformer Technology Seminar Stray Flux Control

siemens.com/answers© Siemens AG 2016 All rights reserved.

Siemens Transformer Technology SeminarStray Flux Control

Pomona CA, May 24-25, 2016

Siemens AG – Transformers

© Siemens AG 2016 All rights reserved.

Stray Flux Control


Page 2



Why highlight Stray Flux Control

Page 3

• Keeping products at the forefront of development

• Increased power transmission needs have led todetailed consideration of losses

• SIEMENS has had a special focus on stray fluxcontrol for more than 30 years

• Committees and publications on stray flux control

• ICEM, CEFC, Compumag, ISEF, IGTE Symposium

• Compel, IEEE Trans. On Industry Application, IEEETrans. on Magnetics


0

50

100

150

200

250

300

1960 1970 1980 1990 2000 2010 2020

Stra

ylo

ss(k

W)

Production year

tap +

tap 0

tap -


Page 4

Powerful computational tools

• Detailed analysis of complex geometries

• CAD tools and in-house developedpreprocessors

• Gives a quick overview and allowsidentification of eddy losses in structuralsteel parts

Committed to decreasing losses

• Illustration of the stray loss decrease

• Comparing similar 150 MVA

• Long term advances by adopting newtechnologies

• Customer advantage by decreasedoperating costs



Current practice and development

Page 5

• Advantages by decreased stray flux losses

• Higher efficiency

• Smaller transformers may be used

• Reduced operating costs

• Safer operation of transformers with strayflux control:

• Avoids local overheating

• Avoids accelerated aging of oil and gasbubble generation

• Appearance of stray flux losses

• Windings, tank, clamping plates, tie barsand yokes

• The crucial step to loss-control

• Calculation of the stray flux distribution

• Experience and ongoing research

• Fast solution of complex problem

• Validated and reliable solutions

Stray flux in transformers Benefits of controlling stray flux



Page 6

State of the art software and capabilities

• Nonlinear, anisotropic materials

• Eddy current and hysteresis losses

• Static, time-harmonic (with nonlinearity),transient, transient with DC bias, coupledcomputations

Comparison of the losses in transformers

• Larger units require special knowledge

• The Siemens approach guarantees costeffective and safe solution

0%10%20%30%40%50%60%70%80%90%

100%

40 150 200 400 500 800Power rating (MVA)

Ohmic loss Eddy loss in windings Stray loss

Percentage of stray losses in load losses on units of differentpower ratings



Page 7

Continuous testing and validation

• Comparison of the calculated andmeasured temperature

• Verification of the results and comparisonagainst measurements

Optimization of designs

• Check all critical points

• Understanding the stray flux distribution

• Detailed 3D analyses

• Optimize the shielding solution

• Develop a special shield arrangement



We can offer:

Page 8

• Access to state of the art software to provide accurate resultsand in-house preprocessors developed to reduce the timetaken to conduct an analysis

• Ability to calculate the stray flux change due to phenomenasuch as geomagnetically induced currents to ensure secureperformance of the transformer during operation

• Experience in reduction of overall losses while finding theoptimal cost efficiency to keep operating costs as low aspossible for our customers

• Results verification through cross-checking calculationsagainst measurements

Detailed stray flux loss simulation models

1200 MVA, 242/24 kV Transformer - 3D FEM models lead to perfect calculation-results of real temperature effects as verified by thermal scanning

© Siemens AG 2016 All rights reserved.Page 9

Siemens AG - TransformersContact

Martin StösslHead – Global Technology CentreE T TR LPT GTC

Elingasse 38160 WeizAustria

Phone: +43 (51707) 71417Mobile: +43 (664) 80117 71417

E-mail:[email protected]

Siemens.com/transformers

mailto:[email protected]