Abstract:
A Power quality problem is an occurrence manifested as a nonstandard , voltage, current or frequency that results in a failure or a mis-operation of end user equipments. Power quality is certainly a major concern in the present era;- it becomes especially important with the introduction of sophisticated devices, whose performance is very sensitive to the quality of power supply. As customers increasingly use process and computer equipment that is highly sensitive to power system interruptions, utilities are being forced to serve these loads with transmission and distribution systems that are at or exceeding capacity. Voltage sags is one of the severe power quality problems, this report addresses all the different aspects related to voltage, sag problem, such as: its types,. consequences and mitigation.
At present, wide ranges of very flexible controllers, which capitalize on newly available power electronics components, are emerging for custom power applications. Among these, the Dynamic Voltage Restorer (DVR) and Distribution Static Compensator (D-STATCOM) are most effective devices. A DVR injects a voltage in series with the system; D-STATCOM injects a current into the system to correct the voltage sag problem. Matlab Simulink/Power System Blockset (PSB) has been used in this work to perform the simulation and analysis of such controllers. The performance of both DVR and D-STATCOM is obtained for various voltage sags such as balanced, unbalanced voltage sags, and reactive power injection and consumption. Comprehensive results are presented to assess the performance of each device as a potential custom power solution.
