DVR with Sliding Mode Control to alleviate Voltage Sags on a Distribution System for Three Phase Short Circuit Fault

Control of most of the industrial loads is mainly based on semiconductor devices, which causes such loads to be more sensitive against power system disturbances. Thus, the power quality problems have gained more interest recently. Voltage sags are mainly caused due to starting of large induction motors, switching of large inductive loads, short circuit faults in transmission and distribution systems and energizing of large transformers. Therefore, different solutions are examined to compensate these sags and to avoid production losses at sensitive loads. Dynamic voltage restorer (DVR) is one of the solutions to realize this goal. For a successful compensation, the DVR must be able to detect the voltage sag and control the inverter to restore the voltage. The Sliding mode control is used for the DVR. Using Sliding mode control to the DVR, additional sag detection method is eliminated. This improves the dynamic response of the DVR and also DVR is able to compensate for any variation in source voltage. In this paper, a DVR with sliding mode control strategy is used to alleviate the voltage sags caused due to faults occurring on the parallel feeders in a three-phase distribution system. The DVR along with the other parts of the distribution system are simulated using MATLAB/SIMULINK.