New at the Faculty of ING: Prof. Leu was already fascinated by the electric arc and its non-linear, "stochastic" behaviour, which is somehow difficult to understand and control, when he was a student.
A. Schreyer: Professor Leu, you have held the Chair of "Electrical Power Supply" at the Faculty of Engineering since the beginning of November 2020. What are your new responsibilities as a professor?
Prof Leu: My task is to support students in acquiring a solid basic knowledge and physical-technical understanding in the field of energy and high-voltage technology, both students of electrical power engineering and industrial engineering at Bachelor's and Master's level.
My teaching includes the courses High Voltage Technology 1, Electrical Power Supply, Electrical Networks and High Voltage and Insulation Technology. Three years ago, I read Switchgear Technology at the HTWK as a substitute. I got to know the conditions here and got the desire to work at the HTWK.
For me, teaching and research form a unit. As researchers, we face new challenges and learn a lot ourselves in the process. Our task is to introduce the students to the projects, i.e. to "break down" the big problems and set workable, interesting tasks. If this is successful, the motivation and learning effect are huge. We are currently starting to work on a DFG project at the HTWK. We are researching the stress on insulation systems caused by high mixed voltages with medium-frequency components. Such voltage forms occur in direct current energy supply systems, but especially in inductive couplers of future energy supply grids, which energetically couple two grids with different voltage levels and forms and at the same time electrically insulate them from each other, i.e. galvanically isolate them. I am used to working with colleagues from a wide range of disciplines. I have the feeling that this will also work well with colleagues from the Institute of Electrical Power Engineering and colleagues from "non-electrical" disciplines. This has many advantages for the students. The industry is looking for engineers who can also evaluate and contribute their specialised knowledge in the context of new and non-specialist aspects.
A. Schreyer: How did you decide to specialise in this area of research and teaching? Did you already know which path you wanted to take later on before you started your studies?
Prof Leu: To be honest, as a student I didn't know which path I would take. Getting my A-levels so that I could go to university was what many people wanted and that's what I wanted too. I played in a band at the time - that was what drove me the most. After a few difficulties, I got a place at the Ilmenau University of Technology. "In between" I worked in assembly at VEB Starkstromanlagenbau Halle-Leipzig. I learned a lot on the construction sites, above all respect for the professionalism and honour of the fitters. Having an idea and creating something is something fulfilling. People also talked a lot about the engineers - the good ones and the less good ones. If anything, I wanted to be one of the good ones. After my basic military service, I started studying electrical engineering in 1986, specialising in plasma and switching technology. It wasn't my choice. But I was still fascinated by the electric arc. I already knew it from welding on assembly lines. Its behaviour was non-linear, "stochastic", somehow difficult to understand and control. Professor Rother, "my" supervising professor at the time, was a physicist who always linked technology with physics. He struggled with us to gain a deeper understanding of things and encouraged us to express what we understood mathematically. Experiment and simulation formed a unit. I liked that. I then became more involved with the physics of the switching arc during my time as a student, in the diploma and doctoral phases and during the time I worked for Siemens (Schaltwerk Berlin). It was about quenching currents in the ampere range as well as in the range of several tens of kiloamperes. But it was also about the behaviour of circuit breakers and disconnectors in the high-voltage grid. One important task was to establish the technology of "controlled switching". I supervised long-term measurements in the Czech high-voltage grid. After this Siemens project, I completed my doctorate in 2000 and worked as a postdoc at Ilmenau Technical University in the field of switchgear technology. I started a family in my private life. I liked the city and its surroundings, especially the forest. I grew up in Halle, more precisely in Halle-Neustadt - not that far from Leipzig.
In 2005, I changed my profession and began to specialise in high-voltage technology. I took on new teaching tasks and worked independently on research projects. In 2010, I was given the opportunity as a research assistant to set up a "High Voltage Technologies" research group, which I led until I moved to the HTWK Leipzig. The group consisted of an average of six doctoral students, whom I supervised and whose work I financed through the research funding I acquired. Many students worked with us - 30 of them completed their studies with a Master's thesis in the field of high-voltage technology. For example, we developed a technology for breaking down biomass for biogas production, a principle for increasing the efficiency of electrostatic precipitators and complex high-voltage insulation systems for AC and DC voltage, as used in energy and medical technology.
A. Schreyer: What skills and interests do you think students who decide to study "Electrical Engineering and Information Technology" should have?
Prof Leu: Students should be willing and enjoy developing a basic technical understanding and working with it - responsibly, competently, creatively and communicatively. Students who like to think logically, mathematically and in terms of physics and technology and who endeavour to work in a solution-oriented and disciplined manner will be successful. It is the task of the teaching staff, especially the professors, to provide support.
A. Schreyer: What new projects would you like to realise in the future?
Prof Leu: I am very interested in the new technology for power supply with direct current. There are many physical effects that need to be known and quantified in order to develop sophisticated technical solutions for new equipment. Before Christmas, we applied for a ZIM project in which we will rethink the mapping of direct and alternating voltage and build corresponding prototypes. I'm looking forward to that.
