Refurbishment of SVCs can extend equipment life and enhance power quality. This paper describes a recent SVC project where a 20-year-old installation was refurbished and upgraded with changing of all SVC main components (thyristor valves, cooling system, and control system) and some of the aging substation components (a new and redesigned 2 nd harmonic filter bank). Utility transmission system power quality with respect to harmonics and voltage flicker was also enhanced with the upgrade of the SVC. This paper describes the methodology used and the approach for the project. The power system studies performed for this project includes harmonics, voltage flicker, transients, losses, and reliability/availability as described in this paper. Power quality measurements, before and after the upgrades are described in detail.