Hydromechanics of Variable Speed Turbines

Abstract

Variable speed generators have recently become available at a reasonable cost. There has been significant interest in applying this technology to hydroturbines, possibly offsetting the need for adjustable blades or gates. Using variable speed turbines to enhance flow control is investigated theoretically and from similitude calculations. Turbine discharge may increase or decrease with rotational speed, depending upon the characteristics of the individual turbine, i.e., specific speed. While the analysis indicates that the variable speed capability does not have a great potential as a flow control mechanism, a turbine designed with the variable speed capability in mind may enhance the performance and range of operation.