Dr. techn. Thomas Fabian

Dr. techn. Thomas Fabian

I'm a physicist working on power systems.

I enjoy tackling a complex problem, identifying its structure, and breaking it down into solvable subproblems. This approach has always worked well for me. That's how I was able to calculate the current through a graphene lattice of 800,000 atoms, scale state estimation, power flow and optimal power flow to distribution networks with tens of thousands of nodes, and optimize several hours' worth of coupled switching decisions for a transmission grid.

I’ve worked at the university, at Siemens, and now at the Fraunhofer Institute — both in small teams and on large collaborative projects. I enjoy sharing my insights: with business stakeholders, at conferences, or in front of a room full of students.

What drives me is learning new things, working across disciplines, and helping to make the energy transition a success. Otherwise, I’m usually riding my road bike or taking pictures with my camera.


Fraunhofer IEE

Expert Researcher — since October 2024

I'm a power-system optimization expert at Fraunhofer IEE in Kassel.

For the TSO project MCCS (Elia / 50Hertz), I designed and implemented the algorithmic core and interfaces for a multi-timestep, day-ahead voltage-optimization service for transmission grids with a small Scrum team. I helped align requirements and prioritize features with business stakeholders. The software is in production.

In the research project kurSyV, I explore how to free up hosting capacity in stressed distribution grids through curative actions — using the short-term overload headroom (TATL) of equipment to admit more renewable generation, instead of reinforcing lines.

Read more about constraints in optimization and in life →


Siemens Grid Software

Software Engineer — 2022 to 2024

At Siemens Grid Software in Vienna, I developed algorithms for a novel grid-analysis application that performs calculations across high- and medium-voltage levels: I designed and implemented distributed versions of state estimation, power flow, and optimal power flow. The software is deployed at a large European distribution system operator and performs calculations on networks with more than 50,000 nodes.

I also represented Siemens in the Industry for Redispatch (I4RD) research consortium, where I defined requirements for grid control systems to enable industrial assets to participate in the redispatch process, and extended the Siemens software in a proof of concept.


PhD & Postdoc — TU Wien

Doctoral Student & Postdoc — 2017 to 2022

I advanced the understanding of quantum phenomena in 2D materials via large-scale numerical simulations of quantum systems, in close collaboration with experimental groups (RWTH Aachen, ETH Zürich). I taught exercise classes in Analytical Mechanics and co-supervised B.Sc. and diploma students.

Read about these articles:

A beautiful pattern in bilayer graphene (2018) →

A beautiful pattern in graphene (2022) →

Why care about beautiful patterns? Because they indicate some underlying robust quantum phenomena, which one can potentially use in an application!


Education


What I work with

Languages: German (native), English (C1), French (B2)

Domain: Power-systems · Theoretical physics (quantum transport, 2D materials)

Methods: Scientific computing · algorithm design · grid modeling · optimization

Software: Python · Java · C++ · CI/CD · unit & integration testing


Selected Publications

D. Mende et al., Curative System Operation in the 110 kV Distribution Grid, Future Power Grids Conference, 2025.

T. Fabian et al., Half-integer Wannier diagram and Brown-Zak fermions of graphene on hexagonal boron nitride, Phys. Rev. B 106 (16), 165412, 2022.

H. Overweg et al., Topologically Nontrivial Valley States in Bilayer Graphene Quantum Point Contacts, Phys. Rev. Lett. 121, 257702, 2018.

Full list: orcid.org/0000-0002-4350-6242