A Comparative Study of the Performance of Synchronous Generators under different Excitation Control Strategies
Abstract:
Synchronous generators play a significant and indispensable role in power system operation, and the problem of properly and adequately controlling them has become a subject of focused research. The principal aim of this study is to investigate the dynamic performance of a synchronous generator connected to an infinite bus under different excitation control strategies. A third-order non-linear model which captures both the electrical and mechanical characteristics of a synchronous generator was developed, and an equivalent model in linearized form was obtained by using the Taylor’s series expansion technique. Then, two of the most currently used control schemes (optimal control and variable structure control) were employed to design two synchronous generator excitation controllers which were simulated in the MATLAB/SIMULNK environment. The linear quadratic regulator, designed on the basis of optimal control methodology, resulted in system dynamic performance that has a maximum overshoot of 0.033rad and a settling time of 1.4s for the rotor angle while the variable-structure sliding mode controller gave zero maximum overshoot and a settling time of 0.4s. However, when the system parameters were varied, the sliding mode controller was able to maintain system stability while the linear quadratic regulator failed to do the same. For instance, when one of the parameters was reduced by 42%, the sliding mode controller was able to eliminate system oscillations within 0.5s. ORDER COMPLETE MATERIAL FROM CHAPTER 1-5
