Application of adjustable speed hydro (ASH) machines in the Norwegian power system

The main subject in this paper is the adjustable speed hydro (ASH) machine concept and its potential applications. The ASH machine gives a contribution to increased efficiency in the penstock/turbine system as well as an improved flexibility with respect to the electrical system. By means of its quick response to network events, the ASH machine is able to obtain an increased stability margin and thereby a more safe operation of the power system. On the other hand, this represents new opportunities for the power producer as well as for the system operator in utilising the transmission network even better. The paper has shown that transmission lines appearing as bottlenecks with respect to power demand may increase their transfer capacity as ASH machines are introduced in the network. In turn, this may lead to a postponement of high investment costs for new overhead lines. Furthermore, the paper has given a quantification of how much the power export out of an example region can be increased due to introduction of ASH machines