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The HydroFlex project aims to develop new technology permitting highly flexible operation of hydropower stations. Flexibility of operation here means large ramping rates, frequent start-stops and possibilities to provide a large range of system services. All this within (strict) excellent environmental and social conditions while being economically competitive compared to alternative solutions.

SINTEF Energy Research will for the most part participate on Enhanced generator winding insulation system and performance testing. This is work package 4 and task 4.4

Connecting a power electronic converter to a generator implies new and different voltage load stress to the insulation and field grading systems. One main concern is the implications on the field grading varnish or tape at the end-winding. The winding design and voltage levels are different in a hydro generator compared to high power motors connected to a frequency converter.

This task therefore includes electromagnetic modelling and analysis of the voltage distribution inside the winding and experimental characterization of the field grading material as function of applied voltage and frequency.

Laboratory models of the end-winding will be developed, and the models will be verified by surface electric field measurements. The long-term effect of significant harmonic distortions on the field grading and the insulation systems will be assessed on selected models. 


The task is led by NTNU, and ABB participates as a project partner.

Project website


Published 27 July 2018
Research Scientist
+47 415 24 155

Project duration

2018 - 2022