Static var generators (SVG), also known as active power factor compensators (APFC) or instantaneous stepless reactive power compensators, are the ultimate answer to power qualityproblems caused by low power factor and reactive power demand for a wide range of segments

and applications. They are a high performance, compact, flexible, modular and cost- effective type of active power filters (APF) that provide an instantaneous and effective response to power quality problems in low or high voltage electric power systems. They enable longer equipment lifetime, higher process reliability,improved power system capacity and stability, and reduced energy losses, complying with most demanding power quality standards and grid codes.

The principle of the SVG is very similar to that of Active Power Filter, When the load is generating inductive or capacitive current, it makes load current lagging or leading the voltage. SVG detects the phase angle difference and generates leading or lagging current into the grid, making the nphase angle of current almost the same as that of voltage on the transformer side, which means fundamental power factor is unit. YIY-SVG is also capable of correcting load imbalance.