Mitigation voltage sag using dynamic voltage restorer at adjustable speed drive (ASD)

The huge problem in power quality is voltage sag, normally affected to adjustable speed drive (ASD), optical devices and programmable logic controllers (PLCs). The most main problem to the sensitive load is the voltage sag. In this thesis, focus to mitigate voltage sag affected to adjustable speed drive. The best solutions to mitigate voltage sag by using dynamic voltage restorer (DVR). It is one of the main objectives. Therefore, the purpose of this project is study and analyzes the performance of DVR on ASD during voltage sag. Voltage sag type A and type B with of the sag magnitude and duration had been studied. The behavior of the torque and speed of ASD was studied. This project use Matlab software 2015b to simulate the system ASD without DVR and with DVR. In this simulation create the sag generator model, the asynchronous motor model and design DVR model. The result of the simulation show the DVR can recover voltage sag that can been seen details in this thesis. It can be seen the behavior of torque and speed during on the sag of magnitude and sag of duration. Besides that, this result simulation produces the graph ride-through capability curve depends on speed value. By using the DVR we can see that the efficiency of the magnitude sag can be improved from 0.5 pu at 0.25 s to 0.1 pu at 0.30 s but it took 0.05 s longer to recover the speed. Hence, it can be concluded that the DVR is effective since it can improved the sensitiveness of ASD toward the voltage sags.