Distribution power system has poor power quality and dynamic performance due to insufficient reactive power support during disturbances. Distribution Static Compensator (DSTATCOM) can improve the power quality and dynamic performance of distribution power system. Proportional and Integral (PI) controllers are often used to control the operation of the DSTATCOM for the distribution power system. However, since the power system is highly nonlinear and subject to various disturbances, the PI controlled DSTATCOM cannot provide optimal performance for different operating points. More robust controllers such as the one based on fuzzy logic approach are required for the DSTATCOM to provide adequate dynamic voltage control and to improve power quality and stability of the distribution power system. This paper presents the design of a fuzzy logic based controller of a 3MVA DSTATCOM for improving the power quality and stability of a distribution power system. Grey Wolf Optimization (GWO) algorithm has been used to tune the scaling factors of the fuzzy logic controllers. Comparison study of PI controlled and fuzzy logic controlled DSTATCOM for improving the power quality and dynamic performance of a distribution power system is simulated using SimPowerSystem in MATLAB/Simulink environment. The performances of the DSTATCOM controllers are evaluated during grid side voltage sag and load variation. The simulation results in MATLAB/SimPowerSystems show that the fuzzy logic controlled DSTATCOM controller provides better system dynamic response and hence improves power quality and stability for the distribution power system

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