Power-quality improvement using series FACTS
The chapter has developed simple modeling for the series FACTS (SSSC and IPFC) into NR-RCIM load flow method that can be used to analyze and improve the power quality. The developed models are based on current injection approach. In this modeling, the series controllers are represented as injected currents at the terminals of their impedances. These currents are calculated in terms of the specified power flow and buses voltage. The injected currents can easily be implemented in load-flow algorithm without any change in the Jacobian matrix. The parameters of series FACTS can be updated during the iterative process using simple equations based on their basic equivalent circuits. In these developed series controllers, the real and/or reactive power flow in single- or multiline transmission system can be controlled; the selection of appropriate initial values of FACTS devices is not required; the problem that happens when the series FACTS device is the only link between two areas has been solved; the structure of the admittance and Jacobian matrices has been kept without change. Consequentially, the complexity of load-flow algorithm with series FACTS has been reduced.