KOLEKTOR ETRA has been present as transformer manufacturer for more than 75 years. Specializing in the manufacturing of power transformers rating up to 500 MVA and 420 kV the company is focusing its activities mainly in technical areas like loss and noise level reduction. The innovation, competence, reliability and after sales service are the features which characterize the company.

Cooperation with SimTec company started in 2010 when KOLEKTOR ETRA switched to ANSYS finite element code. The cooperation encompasses training courses for ANSYS software and regular technical support, which is of highest quality concerning the in deep solutions in the technical field as well as prompt responses concerning installation and other software connected issues.

KOLEKTOR ETRA is using ANSYS software for structural analyses of all critically loaded mechanical parts, like transformer housing, magnetic core support structure, etc. For example, the critical load cases of transformer housing are:

  • vacuuming of the transformer before it is filled with oil and
  • dead load of transformer or magnetic core during transport manipulation.

The analyses enable us to tackle not only the issues of the structure reliability and integrity during its lifecycle but also the optimisation of a structure in order to design it better in terms of material usage with regard to the production costs and its electrical performance.

An example of structural analysis of the tank during filling with oil is represented in Images 1 and 2. Image 1 presents the deformation of the tank and image 2 the equivalent stresses. The equivalent stress during the transformer lift is presented in image 3.

For necessity of power transformers heat transfer problems, we are using Fluent as primary tool for cooling analysis. A preliminary study of convective heat transfer on a cooling element is obtained so analytical calculations can be performed for development of a computer code.  With specific geometry and buoyancy driven convective flow, this is necessary procedure to find specific and average surface heat transfer coefficients. An overall picture of oil and air streaming is also found so the properties of flow can be approximated for measurement setup verification.