Development and Simulation of Dynamic Voltage Restorer for Voltage SAG Mitigation using PWM Firing Control Strategy

The Dynamic voltage restorer is custom power device. Which is utilized to mitigate the voltage at load terminals. Power quality is one of major concerns in the present era. It has become important, especially, with the introduction of sophisticated devices, whose performance is very sensitive to the quality of power supply. Power quality problem is an occurrence manifested as a nonstandard voltage, current or frequency that results in a failure of end use equipments. One of the major problems deal at here is the power sag. To solve this problem, custom power devices are used. One of those devices is the Dynamic Voltage Restorer (DVR), which is the most efficient and effective modern custom power device used in power distribution networks. DVR injects required voltage in series with supply voltage through injection transformer for correcting voltage amplitude, phase and harmonic component into line. This paper presents development, simulation and analysis of a Dynamic Voltage Restorer (DVR) using MATLAB/ SIMULINK. To enhance the voltage sag restoration capability of the DVR, this paper deals with the development of a control structure using a Discrete PWM pulse generator. Results obtained shows that the developed DVR has good capability to starch the voltage level during voltage sag conditions. supervisory control and data acquisition (SCADA) system, with some timing schedule, or with no switching at all. The disadvantage is that, high speed transients cannot be compensated. Some sags are not corrected within the limited time frame of mechanical switching devices. Transformer taps may be used, but tap changing under load is costly. Another power electronic solution to the voltage regulation is the use of a dynamic voltage restorer. DVRs are a class of custom power devices for providing reliable distribution power quality. They employ a series of voltage boost technology using solid state switches for compensating voltage sags/swells. The DVR applications are mainly for sensitive loads that may be drastically affected by fluctuations in system voltage.