Abstract: Modern AC supply system is characterized by two kinds of power i.e Active power and reactive power and both of these powers are necessary for the proper functioning of modern AC supply system. Active power represents the useful work done while reactive power represents the artificial loading and limits the flow of Active power through the AC supply system thereby decreasing the efficiency of existing system. Reactive power provides some positive attributes to the supply system by maintaining system voltage which is necessary for the flow of active power. Reactive power is also necessary for electromechanical energy conversion because it is required for generation of magnetic field which is essential for the energy conversion. If the flow of reactive power in AC supply system is localised then the efficiency of existing system can be increased. This work presents the reactive power compensation by D-STATCOM in distribution system feeding induction motor load under varying loading conditions. Firstly a supply system of line to line voltage 50 Hz is simulated in MATLAB environment and a squirrel cage induction motor load of 75 kW is directly connected. At first under varying loading conditions flow of power from supply to motor is recorded and analysed. Then D-STATCOM is designed using voltage source converter (VSC). Suitable filter is to be selected for smoothening the current waveform which will be injected by D-STATCOM. A suitable control algorithm should also be selected for the generation of reference voltage. This reference voltage will be used to produce triggering pulse for the VSC of D-STATCOM. Then this realized simulation model of D-STATCOM with suitable filter will be connected to the existing system to compensate the reactive power demand of induction motor load. After recording and analysing power flow data under varying loading conditions it was found that D-STATCOM supplies almost majority of reactive power demand of induction motor load while at the same time active power demand is fulfilled by supply system thereby localising the flow of reactive in supply system.

Index Terms: Distributed generation power system, renewable energy resources, energy storage systems, PV system, grid-connected systems.

| DOI: 10.17148/IARJSET.2022.96146