Читать книгу Artificial Intelligence for Renewable Energy Systems - Группа авторов - Страница 25

Considering the constant grid voltage at 240 V (rms value per phase), eigenvalue of both three- and six-phase generator is plotted in Figure 1.18 for increase in load from 0.25 to 1.0 pu. From stator side, real component of stator eigenvalue decreases (increase in magnitude with negative sign) for both three- and six-phase generator, as shown in Figure 1.22a. (No variation was noted in stator eigenvalue I, hence not shown). Decrease in the value of real part of stator eigenvalue was higher (70.8%) than its three-phase counterpart (47.9%). Hence, tendency toward stability of six-phase generator is higher than three-phase generator. On rotor side, increase (i.e., decrease in magnitude with negative sign) in real component was noted to be same (20.7%) for both three- and six-phase generator as shown in Figure 1.22b. Hence, under load variation, rotor behavior will be the same for both three- and six-phase generator. On real eigenvalue II, a slight increase in the value for three-phase (by 4.5%) and six-phase generator (by 1.5%) was noted, as shown in Figure 1.22c. Also, a very small decrease in real eigenvalue III for six-phase (by 3.2%) was noted with 17.1% variation in three-phase generator as shown in Figure 1.22d. Hence, both rotor and damper winding behavior will be approximately the same for both three- and six-phase generator. Since, variation in real eigenvalue I was not noted, and hence not shown.

Figure 1.22 Change in real/real component of generator eigenvalue due to load variation. (a) stator eigenvalue, (b) rotor eigenvalue, (c) real eigenvalue II, (d) real eigenvalue III.