Operation and control of static var generator for voltage unbalance mitigation

Voltage unbalance has a great impact on power electronics equipment. This paper provided a detailed analysis of SVG performance under unbalanced voltage with traditional control method. Furthermore, a novel control strategy was proposed to mitigate voltage unbalance and at the same time extend the functions of SVG. Besides compensating reactive power, SVG can also mitigate unbalanced voltage at the point of common coupling (PCC) when severe negative sequence voltage exists. The SVG operates as a voltage source controlled by the negative sequence voltage at the PCC. The relationships between all the parameters and the compensating characteristics were analyzed in detail. Simulation and experiment results verify the satisfactory performance of the SVG in mitigating voltage unbalance with the proposed control strategy.