Power Quality Improving Operations of a Flux-Lock Type SFCL Integrated With Voltage or Current Controlled-Voltage Source Inverter

In this paper, the flux-lock type superconducting fault current limiter (SFCL) integrated with a voltage source inverter (VSI) controlled with its output voltage or current is proposed and its operations for power quality improvement are investigated. The suggested equipment, which consists of a flux-lock type SFCL and a VSI, can limit the fault current in case that a short-circuit happens by the operation of the flux-lock type SFCL. In addition, it can compensate the reactive power and complement the active power that the non-linear load requires by controlling VSI's output voltage or current and thus, perform the power conditioning operation, the demand side management (DSM) and the uninterruptible power supply (UPS). The specification for the suggested model was determined and its various functions such as the fault current limiting and the power quality improving operations were presented and analysed through the computer simulation. The validity of the analysis was confirmed from the analytical results based on the computer simulation and, the advantage and the limitation of the voltage control and the current control for the VSI's power quality improving operations were discussed.