Investigation the DVR As An Economic Solution Method Compared with UPSand Other Conventinal Approaches for Voltage Sag Compensation

Nowadays, Power quality is identified as one of the very serious issues in electric power transmission anddistribution, because of its bad impact on electricity suppliers, manufacturers and users. Generally we can definepower quality as the deviation of voltage, current and frequency from its standard values in a power system.Presently, most of the industries use power electronics conversion and switching for manufacturing andprocessing. These technologies named custom power devices are in need of high quality and reliable powersupply. Among the custom power devices, we can consider Dynamic Voltage Restorer (DVR) as the mosteconomic and efficient solution for various power quality issues. Some of the reasons for this conclusion are asfollows: When DVR is compared with SVC, SVC lacks the active power flow control capability. ThereforeDVR is preferred over SVC. When DVR is compared with UPS, UPS is not only costly but also it requires highbattery maintenance and replacement due to leak. When compared with SMES, DVR has lower cost and higherenergy capacity. When compared with DSTATCOM, DVR is smaller in size and lower in cost. Consideringthese reasons, DVR can be regarded as the most effective custom power device for voltage sag and swellcompensation in distribution systems.