Page 182 - Decision Making Applications in Modern Power Systems

146 Decision Making Applications in Modern Power Systems

FIGURE 5.22 Frequency response with PFC fixed and load composition of induction motors
corresponding to (A) 25%, (B) 75%, and (C) 90% of the total load demand. PFC, Power factor
correction.

(A) 3 (B) 3
5th 2.5 11th
5th
2.5
7th
7th
Voltage magnitude (%) 1.5 2 1 13th Voltage magnitude (%) 1.5 2 1 13th
11th

0.5
0 0.5 0
25% 75% 90% 25% 75% 90%
Load share of induction motors-K Load share of induction motors-K
FIGURE 5.23 Voltage distortion versus load composition, fixed PFC, at bus 3 for (A) Case 2
and (B) Case 3. PFC, Power factor correction.

When K 5 25%, the major share of the aggregate load is still resistive,
causing a large damping on impedance magnitudes, especially at resonant
points. With the increase of induction motors, the damping declines, as seen
in Fig. 5.22. The higher is the share of induction motors, the greater is the