THE EFFECTS OF DYNAMIC MODELS USED IN SYNCHRONOUS GENERATOR ON SMALL SIGNAL STABILITY

Abstract

Generators used in multi-machine power systems are very affected by transient situations such as malfunctions and line breaks. In transient situations, the system becomes unstable, and oscillations increase. In particular, order modeling of synchronous generators effectively eliminates transient stability situations. To analyze this in the best way, a small signal stability analysis is performed. This study was carried out in the MATLAB-based Power Systems Analysis Program (PSAT), using the 2nd-order and 5th-order models of the synchronous generator for small signal stability analysis in a 3-machine 9-bus power system. While the 2nd-order model is used as the traditional model in synchronous generators, the 5th-order model has been developed as a dynamic order model. Especially in the 5th-order model, it was developed based on a sub-temporal model for better damping of the system. In the comparisons made in both order models, the real and imaginary values and participation factors are shown in figures, while the eigenvalues, damping percentage, frequency, dominant values, and operating modes are presented in tables. By using both order models in the synchronous generator, the number of eigenvalues of the system was determined. The results obtained showed that the 5th-order model gave better results in small signal stability analysis.