It's often the small things that make all the difference. Cable sleeves, for instance, that connect two cable sections with each other electrically. These components are extremely important for the SüdOstLink, the planned “electricity highway” that is to allow energy to flow from Saxony-Anhalt to Bavaria. A route of more than a thousand kilometres of cable requires significantly more than 500 of these connecting elements.
“But cable sleeves are the most critical component,” says electrical engineer . They are the most vulnerable component in the DC-based cable system. “Overheating, partial discharge or breakdowns can become a problem in these live components.” However, the failure of a single sleeve can lead to a considerable downtime of the entire connection, explains the researcher, who is funded by TU Darmstadt as an Dr Yvonne Späck-Leigsnering. The programme is intended to support outstanding scientists on their career path. Athene Young Investigator
Durable robust cables
Climate change is forcing a radical restructuring of electrical power generation, its transmission and conversion, states Dr Späck-Leigsnering. HVDC cable systems are an important part of this necessary transformation. They need to have a long service life, be reliable and resilient, add the 33-year-old, who heads the “QuinCE – Quasistatics in Computational Engineering” research group at the at TU Darmstadt. In times when equipment and systems are increasingly being operated to the limit, “fundamentally new, simulation-based design approaches are needed in development,” she says. Institute for Particle Acceleration and Electromagnetic fields (TEMF)
The researcher is looking for solutions. With the help of mathematical modelling and field simulations, for instance, she traces the influences and causes that lead to the failures. Simulation analyses are combined with experimental investigations in the high-voltage laboratory. Field simulations provide an insight into the inside of the device, such as the cable sleeve. This means that electrical and thermal loads can be analysed over space and time. Sensitivity analyses then facilitate the identification of weak points and important design parameters. “Otherwise you would first have to examine a hundred sleeve designs in the high-voltage laboratory,” she explains.
One of the aims of her research is to provide engineers with field simulation tools for optimising cable sleeves and other electrical equipment such as electrical machines. A topic that she has been working on since 2020 in a research cooperation with TU Munich with Professor Myriam Koch. Yvonne Späck-Leigsnering, her colleague TU Vice President Professor Herbert De Gersem, and Professor Koch successfully held a virtual symposium on the theory and practice of innovative HVDC technology in January 2022 – with over a hundred participants from ten countries.
The scientist developed her interest in working at the interface between high-voltage technology and theoretical electrical engineering at an early stage in her studies. “One of the best moments in research is when simulation and experiment go well together,” she says. She completed both her bachelor's and master's degrees in at TU Darmstadt. Electrical Engineering and Information Technology
She wrote her bachelor's thesis at Chalmers University of Technology in Sweden, and focused on insulating materials during tests in the high-voltage laboratory. Her master's thesis won her the Heinrich and Margarete Liebig Prize at the TU, and in May of this year Yvonne Späck-Leigsnering will also take up the first of the Association of Friends of TU Darmstadt, which promotes international mobility. She will spend half a year in research at TU Graz, which she is very much looking forward to – together with her husband and their two children. Ernst Ludwig Mobility Grant
In Graz, she will be focusing on electrical machines – such as the electric car. She wants to continue focusing on insulating materials in Darmstadt, for instance in HVDC technology. She also plans to organise an exchange with Sweden's Chalmers University of Technology, “which is one of the leaders in this field”. Her creed is to learn from each other. She is doing so with the support of the Athene Young Investigator programme.
Just how much Yvonne Späck-Leigsnering appreciates the working conditions at TU Darmstadt was demonstrated when she turned down the professorship in Theoretical Electrical Engineering offered to her by Kiel University (CAU) in the summer of 2021, opting instead to stay at her institute. “The TU is the the best research environment for me at the moment – with so many exciting major projects,” she emphasises. She is now also a member of the joint project that TU Darmstadt is running together with TU Graz and Johannes Kepler University Linz. “Computational Electric Machine Laboratory”