SOGI-FLL Grid Frequency Monitoring with an Error-Based Algorithm for a Better Response in Face of Voltage Sag and Swell Faults

The SOGI-FLL (second-order generalized-integrator frequency-locked-loop) is a well-known and simple adaptive filter that allows estimation of the parameters grid voltage with small computational burden. However, this structure has shown to be sensitive events sags swell faults, especially deeply distort estimated frequency. In paper an algorithm proposed face fault modifies SOGI-FLLs gains in order achieve better transient response reduced perturbation uses SOGI’s instantaneous absolute error detect change during fault. Moreover, average used for returning normal operating conditions. value obtained by means single low pass (LPF). approach easy implement represents burden being implemented into digital processor. performance evaluated using simulations real-time Typhoon Hardware Loop (HIL) results.