Variable speed pumping in thermal and nuclear power plants: Frequency converter versus hydrodynamic coupling

In this paper, a comprehensive case study analysis of flow control methods and appropriate technical implementations for high-power pump systems employed in thermal and nuclear power plants or heating plants will be presented. The main attention is focused on a comparison of two advanced variable speed control strategies employing VSD with frequency converter and VSD with hydrodynamic coupling. In addition, we have included comparison with conventional flow control methods like throttling, bypass and on-of control. The calculations were performed in the software, which we have developed for design, optimization and sophisticated comparison of these drives. It is presented the methodology and developed models for evaluation of the whole drive chain from hydraulic system over pump, drive components and power supply.