Three Phase System Multi Level Inverters or a Chain of Single Phase Inverters Used in the DVR Topology

Abstract

in this paper, the performance of the DSTATCOM and the DVR used for the load bus voltage control have been analyzed and compared when a nonlinear load is connected across the load bus. Both of these compensators are used under closed-loop voltage-control mode. The control The voltage related power-quality (PQ) problems, such as sags and swells, voltage dips, harmonic distortions due to nonlinear loads and voltage unbalancing in electrical power distribution systems, have been a major concern for the voltage-sensitive loads. Load voltage regulation using VSC for different grid-connected applications has been recently attempted. With the increased use of power-electronics devices in the consumer products, the loads are becoming voltage sensitive and nonlinear in nature. Depending up on the applications, these loads are connected to the distribution system having varying voltage and power levels. Also the radial feeders of the distribution system to which these loads are connected have varying length and short circuit current (SCC) levels. This depends upon the location of the load, distribution system size, and its voltage and volt-ampere (VA) ratings. This leads to the wide variations in the Thevenin?s equivalent feeder impedance looking from the load side. If the load is connected at the end of the long feeder and has small short circuit current value, it is called a weak ac supply system (or non-stiff source).