A comparative study of fish passage conditions by test rig experiments

This paper presents the outcomes of a test rig measurement campaign for quantifying fish-relevant pressure through two axial turbines designed for a large hydropower plant: a propeller and a double-regulated Kaplan machine. In propellers, the runner blade angle is fixed, which simplifies operation at sites where discharges do not vary considerably. In Kaplan turbines, the runner blade angle is adjustable, which accommodates a wider range of operational discharge. Turbine suppliers must often analyse the two alternatives in project development because some hydropower plants may be equipped with both types of axial turbines. Pressure conditions are more favourable in propeller machines than in Kaplan-type turbines.