Kaplan and Bulb turbines can operate at a high efficiency for a wide range of flow rates and heads due to their double-regulated characteristics, which allows adjusting of the positions of both wicket gates and runner blades. The maximum efficiency is achieved by determining the optimal runner blade angle to wicket gate positioning for a given head, which is called a combination (CAM) curve. These curves are initially generated from scaled model tests and are later on validated in the field by index testing. The index testing is usually costly and only provides the combination curve for a single value of the head. The automatic optimizing system demonstrated in this paper measures and calculates the optimal positioning between the wicket gate and runner blades at the various heads. Important variables are measured to determine the turbine efficiency, such as power, net head, and flow rates. The system interfaces with the governor to test the combination that maximizes the efficiency during normal operation of the machine. This system is already installed in three units operated by Enel Green Power, who economically and technically supported this research. This paper presents the efficiency gains achieved using the automatic optimizing system. The efficiency gain will either result in an increase of output power at normal operation, or can reduce the water volume used to produce the same output power, depending on the operational mode of the turbine.
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