News item | 2010-05-03 | 15:45 PM

Joint research between Vattenfall R&D and Uppsala University on hydropower generators

The Swedish hydropower industry is facing new challenges. With the majority of the plants built in the 1950s and 1960s, a considerable part of the existing machinery has now served its time and needs to be refurbished or replaced.

At the same time, the use of hydropower for regulation purposes is increasing concurrently with the large-scale installation of other renewable sources. Hence, old technical considerations need to be recalled and new questions need to be answered.

Collaboration between Vattenfall and Uppsala University
Since 2007, Vattenfall R&D is involved in a research project together with Uppsala University intended to study the mutual electromechanical interaction between hydropower generators and the power system. The project involves development of mathematical models for numerical studies as well as construction of experimental equipment and on-site measurements.  

Currently, the research team is preparing measurements planned to take place during a large-scale black-start test later this year. The test involves several large hydropower machines and the test grid is being monitored using so-called Phasor Measurement Units (PMUs). The idea is to synchronise measurements of voltage, current, magnetic flux, shaft speed and torque on some of the generators with the PMU data in order to elucidate some effects of electrical transients on the machines  

In January 2010, the hydro-generator test rig “Svante”, shown in Figure 1. was taken into operation. Svante is a 185 kVA, 12 pole synchronous motor rebuilt to resemble a hydropower generator, including laminated poles, damper winding and parallel stator windings. In addition, the rig is equipped with a number of special features to allow for studies of for example non-centred rotor operation and air flow inside the machine.

For more information about this, please contact:
Johan Lidenholm,, +46761-478830

Test rig Svante

The hydropower test rig Svante in the Ångström laboratory in Uppsala.

On Thursday the 29th of April 2010, Johan Lidenholm presented his licentiate thesis titled “Transient electromechanical analysis of hydropower generators using field and circuit models”. A copy of the thesis can be sent upon request. Further information and abstract can be found online at