Design of a Statcom-Based Harmonic-Free Static VAR Compensator for Load Balancing Purposes

In this paper, a bipolar (capacitive and inductive) static VAR compensator is built on the basis of statcom fundamentals. The designed compensator exchanges wide range of pure reactive power with the ac supply without significance of real power contribution. No harmonic generation is associating the compensation process, thus no filtering is required. The compensator is built of two single-phase statcoms connected in parallel. One of them represents a static linear synchronous condenser at the ac supply fundamental frequency, while the other represents a harmonic-free linearly and continuously controlled reactor. Each statcom is built of a half-bridge voltage source inverter shunted by two dc capacitors and exchanges pure reactive power with the ac supply through a series reactor. The reactive power of each statcom is controlled linearly by the modulation index of its voltage source inverter. A demonstration system for this compensator is designed and tested on PSpice.