Andreas Ridder, M. Sc.

Research Staff Profile

• Research Topic - Investigation of additional losses in the rotor windings of inverter-fed salient-pole synchronous machines in pumped-storage power plants
  What is your research topic and what is it about?

  In large hydro power plants, salient-pole synchronous machines are typically used for electromechanical energy conversion. When the machine is operated with a frequency converter, the additional harmonics in the stator current induce voltage in the damper and field windings. Due to eddy current effects, the resulting alternating currents lead to additional frequency-dependent copper losses, which are the subject of my research. I am developing various models to estimate these effects during the machine’s design phase and test the results on the institute’s test bench for large machines.

  Why is your topic relevant?

  Pumped storage hydropower plants provide the world's largest energy storage capacity for electricity grids, and will remain essential as the proportion of fluctuating energy sources increases. In this context, the importance of rapid response times and adjustable capacity in pump and turbine modes increases, as does the need for ancillary services to control active and reactive power. This can be achieved by using variable-speed pumped-storage power plants, which have a frequency converter connected between the electrical grid and the stator terminals of the synchronous machine.