Advances in the determination of control parameters for static compensators

The authors discuss the advantages of synchronizing modern programmable controllers to the phase-locked loop (PLL) synchronization circuit for power electronic control applications. Accurate phasor values of system quantities are required for fast feedforward or feedback control of the firing angle of static compensators. The combination of a high-speed programmable controller and an accurate high-frequency PLL provides the ability to determine specific phasor quantities of any harmonic in the presence of system unbalances and frequency excursions. The PLL can also provide hardware interrupts to start specific programs at definite times in the power frequency cycle. The measurement and control technique has been applied to static compensators for load balancing, voltage balancing and regulation, and the damping of harmonic resonances. The results of these analog and digital simulation studies are presented