Dynamic interactions of AC-side disturbances and its solutions.

To Power system simulation is crucial for system planning, design, and operations; accurate modeling plays a key role in identifying potential system deficiencies. Recently, various power electronics-based devices such as voltage source converter high voltage direct current (VSC-HVDC) and wind power plants have been integrated into grids, presenting a challenge of system simulation and analysis. A two-area four machine system and IEEE 39 bus system are modeled in MATLAB Simulink. The transient response of the systems under various disturbances such as tripping of transmission line, faults and change in reference values are analyzed. Two stable local modes and one unstable inter area mode are detected in two area system for a step-in voltage reference from 1.0 pu to1.05 pu. The unstable inter area mode is destabilized using PSS. IEEE 39 bussystem is analyzed under various scenarios and it is evident that the system is prone to electro mechanical oscillations when it is subjected to disturbance. But the oscillations are naturally damped out and the system again enters into steady state followingthe disturbance. [ABSTRACT FROM AUTHOR]