Design and implementation of a low-voltage medium power voltage sag compensator

Since 1996, voltage sag compensators have been successfully utilized to protect sensitive loads against short-term voltage disturbances. Once the performance of a compensator is strongly dependent on its operation philosophy, besides the design and specification of its main components, careful analysis should be taken, in order to achieve a system with the required compensation capability. This paper discusses the main aspects involved in the design and implementation of a low-voltage sag compensator. The design methodologies presented are used and evaluated in the development of two prototypes: a full-scale prototype (440 V/500 kVA) and a small-scale prototype (5 kVA/220 V).