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 3 Advanced Power Solution Sdn Bhd. salleh@pc.jaring.my feeders and by installing uninterruptible power supplies (UPS). However, the PQ problems are not solved completely due to uncontrollable reactive power compensation and high costs of new feeders and UPS. The D-STATCOM has emerged as a promising device to provide not only for voltage sags mitigation but a host of other power quality solutions such as voltage stabilization, flicker suppression, power factor correction and harmonic control [4]. The D-STATCOM has additional capability to sustain reactive current at low voltage, reduce land use and can be developed as a voltage and frequency support by replacing capacitors with batteries as energy storage [5]. 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.