Heat-Loss Based Method for Real-Time Monitoring Method for Hydroelectric Power Plant Efficiency

In energy transition scenarios, hydropower remains the largest source of renewable electricity generation. However, with respect to other means of renewable energy exploitation, like wind turbines or photovoltaics, very few technological advancements are to be expected, due to the technological maturity of hydropower turbines. Therefore, an increase in power production of hydropower plants can only be possible thanks to an optimization of the operation and maintenance policies, leading to improved performance, reducing energy losses and downtimes. This work proposes a practical approach to the continuous monitoring of the operational conditions of hydropower plants through the non-invasive measurement of the electrical efficiency of the generator group. To achieve this, a heat-loss based method is introduced, which enables the measurement of both the electrical generator losses and the electrical input power, along with their associated uncertainties. This method is applicable for plants of any size, does not require a production shutdown, and, since it is applied to the electrical generator, can be used with different turbine types, including Kaplan, Francis, and Pelton. It also relies on relatively simple instruments such as thermo-cameras, thermo-resistances, thermo-couples, and flow meters to measure key variables, including cooling water inlet and outlet temperatures, electrical machine external and frame temperatures, undisturbed ambient temperature, electrical power absorbed, and cooling water flow rate. The proposed methodology has been tested and validated through the application to a laboratory test rig. In all test conditions, the heat loss-based method showed a smaller relative error than the standard efficiency measurement methods.