Improved System Performance by Integration of Adjustable Speed Hydro (ASH) Machines

Abstract The main purpose of this paper is to show how theAdjustable Speed Hydro (ASH) machine behaves with respect totransient and dynamic conditions in power systems. The ASHmachine gives a contribution to increased efficiency in ,thepenstocWturbine system as well as an improved flexibility withrespect to the electrical system. By means of its quick response tonetwork events, the ASH machine is able to obtain an increasedstability margin and thereby a more safe operation of the powersystem. With proper location and parametrisation of Power SystemStabilisers (PSS), the ASH machine can make considerable supportto damping of large scale power oscillations in transmissionnetworks. On the other hand, this represents new opportunities forthe power producer as well as for the system operator in utilisingthe transmission network even better. The paper has shown thattransmission lines appearing as bottlenecks with respect to powerdemand may increase their transfer capacity as ASH machines areintroduced in the network. In tum, this may lead to a postponementof high investment costs for new overhead lines. Furthermore, thepaper has given a quantification of how much the power export outof an example region can be increased due to introduction of ASHmachines.6 Halama