A Review on Reactive Power Compensation Technologies

In general, the problem of reactive power compensation is viewed from two aspects: load compensation and voltage support. In load compensation the objectives are to increase the value of the system power factor, to balance the real power drawn from the ac supply, compensate voltage regulation and to eliminate current harmonic components produced by large and fluctuating nonlinear industrial loads .Voltage support is generally required to reduce voltage fluctuation at a given terminal of a transmission line. This paper presents an overview of the state of the art of static VAR technologies. Static compensators implemented with thyristors and self-commutated converters are described. Their principles of operation, compensation characteristics and performance are presented and analyzed. A comparison of different VAR generator compensation characteristics is also presented. New static compensators such as Unified Power Flow Controllers (UPFC), Dynamic Voltage Restorers (DVR), required to compensate modern power distribution systems are also presented and described.