| dc.description.abstract | The power factor of a synchronous generator, in a European hydropower generation, is
constrained to [0.85, 0.95], and for Norway, it is generally below 0.86. A higher power
factor means more exploited power (active power), and currents through the generator; and
vice-versa. However, relaxation on the constrained power factor for higher active power
generation should be balanced with thermal heating due to more winding currents through
the generator which eventually influences the generator lifetime.
Thus, the measure of temperature evolution in generator metals are vital if the relaxation
of power factor is allowed. In this thesis work, we are developing several thermal models for
air-cooled synchronous generator based on constant, and temperature dependent resistance
and specific heat capacity for metals and fluids (air, water). The developed models are
then analyzed, and state estimation algorithms are applied for air and metals temperature
estimation. The state estimation algorithms, Unscented Kalman Filter, and Ensemble Kalman Filter are compared. Based on computational speed Unscented Kalman Filter performs
better, however, based on estimation accuracy Ensemble Kalman Filter performs better. | en_US |
