Abstract: The concept of flexible alternating current transmission systems devices (FACTs) and custom power devices (CPD) are widely used for improving the flow of power in a transmission and distribution network. The term Power quality and Reliability are becoming very important issues for the sensitive loads connected to the systems. For low voltage distribution system Custom Power Devices (CPDs) such as Dynamic Voltage Restorer (DVR), Distribution static synchronous compensator (D-STATCOM) and Unified Power Quality Compensator (UPQC) etc. are used for improving the quality of power and reliability of supply without affecting entities such as factories, industries, and home etc. Among the Custom Power Devices D-STATCOM is mainly used to mitigate the fluctuation in voltage due to fault and the application of dynamic load which is connected in shunt with the main line that injects or absorbs the reactive current into/ from the line to maintain the flat load voltage profile. In this paper the simulation of D-STATCOM is done by using SIMULINK tool of MATLAB software. The control signal of the D-STATCOM is provided through the discrete PWM generator and PI Controller to improve the quality of power under different abnormal conditions like single line to ground fault (LG) double line to ground fault (LLG), three phase ground fault and the application of Dynamic Load has been described in this paper and the simulation result shows the efficient performance of D-STATCOM under different voltage swell and sag conditions.
Keywords: Power Quality, CPD, D-STATCOM, Dynamic load, FACTS.