Design of a Prototype D-Statcom for Voltage Sag Mitigation

This paper presents the design of a prototype distribution static compensator (D-STATCOM) for voltage sag mitigation in an unbalanced distribution system. The D STATCOM is intended to replace the widely used static Var compensator (SVC). For fast response requirement, the feedforward compensation scheme is employed to enable the D STATCOM to mitigate voltage sag and at the same time correct the power factor, thus acting as a load compensator. The compensation scheme of the D-STATCOM is derived using the symmetrical component method. In this work, the 12-pulse D STATCOM configuration with IGBT has been designed and the graphic based models of the D-STATCOM have been developed using the PSCAD/EMTDC electromagnetic transient simulation program. Accordingly, simulations are first carried out to illustrate the use of D-STATCOM in mitigating voltage sag in a distribution system. Simulation results prove that the D STATCOM is capable of mitigating voltage sag as well as improving power quality of a system.