Page 185 - Hybrid-Renewable Energy Systems in Microgrids

166 Hybrid-Renewable Energy Systems in Microgrids

can stabilize fixed speed wind generator system during grid fault as it is a popular
method for stability augment in terms of cost and simplicity [15,16]. However, in those
studies, only the dynamic analyses have been performed. Small signal stability analy-
sis of fixed speed wind generator system considering series dynamic braking resistor
(SDBR) has been reported in [17]. Another important work that focuses small signal
stability of variable speed wind farm including SDBR is presented in [18]. In addition
to that, this study attempts to study small signal stability analysis of fixed speed wind
generator system as well as transient performance including SDBR. The feature of this
chapter involves fault analysis and interaction of different dynamic modes based on
modal and frequency domain analyses for IG-based wind power generation. Thus, the
study will be helpful in performing modal and sensitivity analyses, which will allow
for determining participation factors to find out the relations between different modes
and state variables. Based on these analyses, impact of machine parameters and dif-
ferent operating conditions are investigated. To demonstrate the effectiveness of the
SDBR, sensitivity, voltage dip, and transient analyses of wind generator are performed
with and without considering SDBR. Time domain simulation software MATLAB/
Simulink is used to carry out the small signal stability analyses.
The chapter is organized as follows: Section 2 introduces the dynamic model of
the FSWT-driven IG including the SDBR. Section 3 presents the modal and sensitiv-
ity analyses. which also comprises the effect of different system parameters with and
without SDBR. The system dynamic behavior under voltage dip with and without
SDBR is investigated in Section 4. The effect of the machine parameters on system
dynamic behavior under voltage dip is depicted in Section 5. Transient analysis of this
system is investigated in Section 6 and the conclusions are drawn in Section 7.

2 Modeling of the system

The studied model system is shown in Fig. 9.1. The fixed speed wind farm comprises
a squirrel cage IG where the stator winding is directly connected to the power grid via
a capacitor bank and a double-circuit transmission line.

Figure 9.1 One-line diagram of the studied system including SDBR.