Generator excitation systems sensitivity analysis and their model parameter´s reduction

Since power systems have large scale, nonlinear parameters, including uncertainty, researchers have presented many methods for model simplification. Voltage dip and transients are known for their importance in dynamic studies and as a result of short circuits or starting a large induction motor, generator excitation systems come into effect in order to compensate voltage oscillations and voltage dips during such transients. This paper will address model parameter reduction of generator excitation systems. An objective function and a simple method for sensitivity analysis will be proposed to identify which excitation parameters are more sensitive and have more impact on generator voltage response. Moreover, the proposed method can be used to determine which parameters do not have significant effect on the excitation system. The objective function will stress voltage dip and overshoot rather than small oscillations and transients. A small stand-alone micro gird, with three induction motors and a generator with IEEE ST2A excitation system have been selected to simulate and verify the method performance.