Benchmark Test of a Variable Speed Unit for Teaching Purposes

Variable speed pump-turbine units have become nowadays an interesting way to increase stability of electrical power networks due to their high level of operating flexibility. Different advantages offered by variable speed pump-turbine units for both pumping and generating modes can be pointed out by means of either reliable simulation models or benchmark test devices. This paper presents a benchmark test of 3.3 kVA of a variable speed unit for teaching purposes. The control strategies for the transformer section and for the machine section are described. Comparisons between simulated and test results performed on this low power system are presented for different cases of operation (SVC effect, reactive power compensation, flywheel effect).