Voltage sag improvement using DVR and SVG in power systems

Voltage sag is the most serious problem of power quality in industrial parks today, which brings heavy financial losses to voltage-sensitive loads. The problem couldn't be solved using one single custom power device, so the coordination of several custom power devices should be considered. This paper proposes a solution using two kinds of custom power devices, which are the Static Var Generator (SVG) and the Dynamic Voltage Restorer (DVR). The paper gives the mathematical models of DVR and SVG in detail respectively, and then presents the detecting methods used in the models of SVG and DVR. Based on the models and methods, a simulation about Suzhou industrial park is performed using MATLAB. Four scenarios of voltage sag events are considered in the simulation, and the result shows that using DVR and SVG to deal with voltage sag is suitable for voltage-sensitive loads in industrial parks.