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The integration of unconventional renewable energy sources on the electrical grid poses challenges to the electrical engineer. This chapter focuses on the transient modeling of electrical machines. These models can be used for the design of generator control, the definition of the protection strategies, stability studies, and the evaluation of the electrical mechanical and thermal constraints on the machine. This chapter presents three modeling techniques the standard d-q equivalent model, the coupled-circuit model, and the finite element model FEM . The consideration of magnetic saturation for the different models is presented. The responses of the different models during three-phase, two-phase, and one-phase sudden short circuit are compared.

In power plants, acoustical signals are generally easier to measure than vibration signals at specific location because the security procedures are restricting the installation of accelerometers during the operation of the hydroelectric group. Specific acoustical measurements have been developed at the Hydro-Québec research center to set some maintenance actions or to gain more information about the operating conditions of the hydroelectric groups. These include acoustical airborne and structure-borne pressure measurements with conventional microphones at different locations around and inside the generator (including a microphone on the rotor) to correlate with vibration signals. Also, several vibration measurements were performed to allow ODS “Operating Deflection shape” of the generator displacement and correlation studies with the acoustic signals. Furthermore, some acoustical intensity measurements for mapping the generator floor permit the illustration of the emission pattern of the generator. All these acoustical measurements are interpreted in terms of operating conditions and specific frequencies. These acoustical and vibration measurements that were performed on several hydroelectric groups will be presented. The main goal of these measurements is to make multiphysics links between the acoustic, vibration and electromagnetic signals to perform non invasive maintenance and increase knowledge of the hydroelectric groups.

To ensure the proper operation of hydroelectric generators, their cooling must be well understood. However, the airflow within such machines is difficult to characterize, and although Computational Fluid Dynamics (CFD) can be a reliable engineering tool, its application to the field of hydroelectric generators is quite recent and has certain limitations which are, in part, due to geometrical and flow complexities, including the coexistence of moving (rotor) and stationary (stator) components. For this reason, experimental measurements are required to validate CFD simulations of such complex flows. Of particular interest is the quantification of the flow within the rotor rim ducts, since it is directly responsible for cooling the poles (one of the most critical components of a hydroelectric generator). Thus, to measure the flow therein, an anemometer was designed. The anemometer had to be accurate, durable, cost-effective, easy to install, and able to withstand the extreme conditions found in hydroelectric generators (temperatures of 45°C, centrifugal forces of 300 g, etc.). In this paper, a thermal mass flow meter and a method for validating its performance, using hot-wire anemometry and a static model of a rotor rim, are described. Preliminary tests demonstrate that the thermal mass flow meter is capable of i) measuring the mass flow rate in the rotor rim ducts with an accuracy of approximately 10%, ii) fitting inside small rectangular ducts (12.2 mm by 51 mm), and iii) resisting forces up to 300 g.