Efficiency Mapping and Weighted Average Efficiency for Large Hydrogenerators

This paper presents the concept of efficiency mapping for large synchronous hydrogenerators, which are useful for evaluating hydropower generation performance vis--vis interconnected intermittent generation to machine efficiency-oriented design. Tests for loss segregation at rated conditions are needed, and models for loss variation along all operational areas are presented. The weighted average efficiency is obtained as the summation of all operating load point efficiencies times related weights, defined according to criteria or from a 2D-histogram of machine operation. The proposed methodology is applied and compared for two machine designs and to an existent machine under operation.