Abstract: Power quality is one of the most important factors in the present days. Power quality problem arises due to abnormal current, voltage or frequency, which results in end user equipment failure. This paper describes the power quality problems consist of a large number of disorders such as voltage sags, swells and its effect on sophisticated loads. For solving these types of problems, custom power devices are used. Dynamic Voltage Restorer (DVR), is one of the most effective and efficient modern custom power device. This device is used in power distribution networks. By using DVR it includes lower cost, smaller size. It also gives fast dynamic response to the disturbances. The dynamic voltage restorer improves voltage waveform and ensures constant load voltage by adding compensated voltage. By finding the differences between desired and measured values, the compensating signals are generated dynamically .If there is any disturbance in the network then dynamic voltage restorer generates injected voltage. If any power quality problem arises in source side then this injected voltage can regulate the voltage at the load terminals. With derived reference load terminal voltages, the control of dynamic voltage restorer is implemented. To verify the performance of proposed system, results Matlab with its simulink and simpower system tool boxes are used.

Keywords: Dynamic Voltage Restorer, Power quality, Voltage Sag, Voltage Swell, Harmonic distortion, Matlab/Simulink.