A Synchronous Condenser System Capable of Eliminating Harmonic Distortion for Grid-Connected Inverters

In recent years, power systems are facing new challenges, such as the connection of a large number of power electronics devices, and synchronous condensers (SCs), which can increase the inertia and short circuit capacity of power systems, are again attracting worldwide attention. Since generator systems using grid-connected inverters, such as offshore wind power plants connected to high voltage direct current (HVdc) system, are sources of harmonic currents, not only SCs but also harmonic filters are required. In this paper, an SC system having a three-winding transformer capable of absorbing harmonic currents for grid-connected voltage source inverter (VSI) and grid-connected current source inverter (CSI) is proposed. First, a simulation model is developed for the systems with VSI or CSI. Also, the validity of the simulation model is confirmed by experimental investigations using laboratory-scale experimental setup. The usefulness of the proposed SC system is investigated through experimental results and simulated results.