Stability Enhancement of AC Microgrid Using Discrete Mode Controllers with Optimum Sampling Frequency

This paper examines the influence of discrete mode controllers with optimum sampling frequency to enhance the stability of the grid-integrated AC microgrid. The damping of low-frequency electromechanical oscillation performance of distributed generators of AC microgrid is analyzed. The AC microgrid is comprised of two renewable energy resources a photovoltaic (PV) farm, a variable wind speed type DFIG wind farm, and another two distributed generators hydro and diesel are based on synchronous generators. The diesel generator is used as a backup source to provide the load demand when the grid is subjected to disturbance and the generation of renewable power is not as per demand. This research investigates the effect of the execution of different discrete type’s power system stabilizers with an optimum sampling frequency to enhance the stability of the AC microgrid. The discrete type time domain mode PSSs such as conventional PSS (Δω-PSS and ΔPa-PSS), MBPSS-4B, and LQG-based PSS controllers are executed on DGs of the AC microgrid for the damping of low-frequency electromechanical oscillation. The MATLAB/Simulink software gives a comparative analysis of the discrete mode controller's response to distributed generators of AC microgrid. The simulation result verified the system performance with an effective operational sampling frequency of discrete time domain mode controllers such as conventional PSSs, MBPSS-4B, and LQG controllers under fault conditions.