The impact of converter´s synchronization during FRT voltage recovery in two-phase short circuits

This article aims to examine the impact of synchronisation methods on transient phenomena occurring during a short-term voltage sag. The study was conducted for several synchronisation algorithms during interference from a short-term two-phase short-circuit. The research results show that in a state of transition of reduced and unbalanced voltage the best inverter results are obtained for fast-synchronisation algorithms which generate a synchronisation signal adequate to the voltage distortion. In contrast, the greatest threat turned out to be big oscillations of active power during work with advanced, time-consuming synchronisation algorithms. These oscillations adversely affect the mechanical components, particularly on the drive train system of a wind power plant if the plant uses the Fault Ride Through procedure.