Porównanie przebiegów nieustalonych w nieliniowym i zlinearyzowanym modelu zespołu wytwórczego pracującego w systemie elektroenergetycznym

The paper presents the investigation results dealing with reconstruction of output waveforms of the nonlinear generating unit model on a basis of the state matrix eigenvalues of the model linearized at the determined working point. There were considered the waveforms of the terminal voltage, the instantaneous power and the field current of a synchronous generator in the case of step and impulse change of the regulator reference voltage. Linearization of the system model allows obtaining the results in analytical form. The exemplary calculations were carried out in Matlab - Simulink environment for the generating unit model consisting of "Configurable Subsystems" blocks enabling the choice of a generator, an excitation system, a turbine and a power system stabilizer model. The waveforms obtained from simulations on the nonlinear model were compared with those reconstructed from the eigenvalues dependently on the model complexity and nonlinearity level. There was also compared the waveform reconstruction accuracy obtained when using the all eigenvalues and when neglecting the eigenvalues of small participation factor absolute values. From the calculations it follows that the influence of the waveform reconstruction accuracy on nonlinearity of the generator magnetization characteristic is dominant, especially for loads close to the rated one. Neglecting in the waveforms reconstructed the eigenvalues of small participation factor absolute values does not result in significant deterioration of the reconstructed waveform quality, while it allows simplifying the system transmittance.