Elfi-Project

Background

Phase 1: Origin of Elfi

The history of Elfi-Project goes back to the early 1960s when Hans Steinbigler, a Ph.D. student at the High Voltage Engineering Institute of the Technical University Munich (TUM), started to develop his first program for numerical computation of electric fields based on the charge simulation method (CSM) [1.1],[1.2]. This program was worldwide the first numerical tool that allowed effective computation of real high voltage arrangements with axial symmetry, long before the finite element method (FEM) was capable to efficiently and accurately enough solve equivalent models. In this initial phase the computers did not have any graphical user interface; the input data sets have been specified by punched cards and the results printed on the paper as listings of numbers representing the field characteristics. But in spite of all these difficulties, the predicted withstand voltage could be confirmed by high voltage tests as described 50 years later by Hans Steinbigler in his talk on "the dawn of electric field simulations".

Phase 2: Graphical UI, HPC, new CSM formulation and 3D fields

End of 1980s and beginning 1990s the introduction of graphical user interface for Unix-Workstations and PCs as well as progress in parallel, high performance computing (HPC) technology gave another "push" to continue the Elfi developments. During this phase Andreas Blaszczyk and Carsten Trinitis joined the team of Hans Steinbigler at TUM. They have been working on a new CSM formulation method [1.3] and the corresponding user interface [1.4] for Elfi 2D. In addition the TUM-team participated in the three following cooperation projects contributing to further progress in the area of 3D fields:

Venus-Project (1988-1990) supported by German Science Foundation as a collaboration between Technical Universities of Karlsruhe, Munich and Hamburg [1.5],
Polopt-Project (1989-1991) funded by German and Yugoslavian governments as a bilateral collaboration between Technical Universities of Sarajevo and Munich [1.6],
Field-Optimization-Project (1992-1997) funded by ABB to explore the use of field simulation in industrial environment and enable a CAD-based optimization [1.7].

After mid of 1990s the Elfi-Project has been discontinued. Hans Steinbigler retired while Andreas Blaszczyk and Carsten Trinitis continued their professional carriers working on related topics at the ABB Corporate Research and the TUM Computer Science Department respectively.

Phase 3: Elfi as a platform for high voltage engineering simulations

Since beginning of 2000s, the tradition of field computations at TUM has been taken over by Frank Messerer who continued the lectures on electric field computations and summarized most of the Elfi-Project results in his handbook on "High Voltage Fields" [1.8].

In 2021 the work on Elfi-Project has been resumed with a goal to create a comprehensive simulation platform based on 2D CSM and 3D BEM electric field computations supporting dielectric dimensioning of high voltage devices [1.9]. The new project includes not only enhancements of the field computation methodology but also all other topics that enable efficient use of simulation in engineering. Of particular interest is the prediction of withstand voltage with a reasonable accuracy. Important highlights of the new project are:

computation of surface charging and its influence on discharge developments within the saturation and restrike stages
integrate a reliable interpretation of field results based on a simplified evaluation of discharge characteristics
effective computation of conducting (DC) and mixed (AC) fields as an extension to the existing capacitive fields
reduce modelling effort by utilizing direct links to CAD-systems and enable full model generation in CAD
enable fast computation (within a few minutes) of large 3D models and their efficient optimization by using HPC-technology

Current Project Team

The core team includes currently the following members with the corresponding responsibilities:

Frank Messerer¹, high voltage engineering, educational software
Carsten Trinitis^2,3 , high performance computing technology, optimization
Andreas Blaszczyk^2,4, high voltage applications, architecture of the simulation platform
Bartosz Dobrzelecki⁵, IT infrastructure, cloud computing

¹Professorship of High Voltage Engineering, TU Munich, Germany
²School of Computation, Information, and Technology, TU Munich, Garching, Germany
³School of Computation, Information, and Technology, TU Munich, Campus Heibronn, Germany
⁴Private Enterprise "Andreas Blaszczyk Consulting", Zurich, Switzerland
⁵Rescale, Global HPC Company (rescale.com), Location: Bydgoszcz, Poland

Project Meetings/Workshops

We arranged several face-to-face meetings and workshops, which significantly contributed to a successful launch of the project and to a good progress. A few photos documenting these events are presented "here".

Acknowledgments

The team members would like to thank Prof. Martin Schulz for hosting the project at the Chair of Computer Architecture and Parallel Systems (CAPS) of TU Munich, Dr. Josef Weidendorfer of Leibniz Computing Centre of TU Munich for advising in IT-questions and Dr. Thomas Müller (formerly with CAPS) for his help in implementation of CAD interfaces. Special thanks go to Michael Jungmann for supporting the project as independent IT consultant.

References

[1.1] H. Steinbigler, Anfangsfeldstärken und Ausnutzungsfaktoren rotationssymmetrischer Elektrodenanordungen in Luft, Dissertation TH München, 1969.

[1.2] H. Singer, H. Steinbigler, P. Weiss, A charge simulation method for the calculation of high voltage fields, IEEE Transactions on Power Apparatus and Systems pp. 1660-1668, 1974.

[1.3] A. Blaszczyk and H. Steinbigler. Region-oriented charge simulation. IEEE Trans. on Magnetics, vol 30, no. 5, September 1994, pp. 2924–2927.

[1.4] C. Trinitis, Entwicklung von Graphikmodulen für elektrostatische Feldberechnung auf der Basis des Graphicsystems GKS unter Wahrung maximaler Portabilität. Diplomarbeit, TU Munich 1990.

[1.5] H. Singer, A.J. Schwab. H. Steinbigler, K. Förger, P. Deister, A. Blaszczyk, M. Wohlmuth, J.A. Gomollon, A. Meroth, B. Schaub: VENUS – An open field calculation system with defined data interfaces. Mat. des 7. International Symposium on High Voltage Engineering (ISH), August 1991, Dresden, paper 11.08 Band: Electromagnetic Field, S. 39-42.

[1.6] Z. Andjelic, B. Krstajic, S. Milojkovic, A. Blaszczyk, H. Steinbigler and M. Wohlmuth. Integral methods for the calculation of electric fields. Scientific Series of the International Bureau Research Center Juelich, 1992.

[1.7] C. Trinitis, Feldoptimierung von dreidimensionalen Isoliersystemen in der Hochspannungstechnik. Dissertation, Fortschritt-Berichte VDI Reihe 21 Elektrotechnik Nr. 242, München 1997.

[1.8] F. Messerer, Hochspannungsfelder, Handbook of Technical University Munich, 2021.

[1.9] A. Blaszczyk, F. Messerer, C. Trinitis, Charge Simulation Method and surface charging computation for design of high voltage devices, accepted by ISH Glasgow, 2023.