Simulation study of power quality compensation system using EDLC for distribution systems

Power quality problems such as voltage sags, voltage distortions, voltage interruptions and frequency or phase variations In distribution systems are serious concerns, especially for semiconductor manufacturing companies, paper mill companies and so on. We have been studying a power quality compensation (PQC) system using electric double-layer capacitors (EDLCs) for distribution systems, which compensates not only reactive powers but active powers for a short period to the systems. It has large capacitors on the DC side. There are two methods for the PQC system, a series connection type and a parallel connection type for loads. We compared them on needed capacities, the compensation ability and so on. Based on the comparison, we selected the parallel connection type for future development. A control system of the PQC system was developed to deliver power to the loads. Finally, detailed digital simulations of the PQC system were carried out and the behaviors were confirmed.