An Improved Islanding Detection Method for a Grid-Connected Inverter With Intermittent Bilateral Reactive Power Variation

An islanding detection method for a grid-connected inverter incorporating intermittent bilateral (IB) reactive power variation (RPV) is described. The inverter output with IB reactive power enables the detection of an islanding. The RPV range is derived in order to eliminate the nondetection zone. The design scheme of variation time in the method is obtained by estimating the transient response due to islanding occurrence. In addition, the effect of the proposed detection strategy on power quality is investigated. The proposed islanding detection method has been experimentally verified on a three-phase grid-connected 6-kW inverter.