Modified cascading modular frequency domain analysis of power systems

The authors present a modular approach for the frequency domain analysis of multiphase power systems based on a modified cascading procedure which produces a reduced model for any composite branch comprising a set of cascaded subsystems. The approach is numerically stable and permits changes in the number of phases within each branch. Extended multi-two-port networks which model both passive elements and independent sources are defined and are used to describe both the reduced composite branch models and their constituent subsystems. The modified cascading procedure incorporates existing nodal admittance matrix techniques and determines all voltages and line currents between branch subsystems using the reduced branch models