Loss-of-mains detection in a household PV inverter: Test of the effect of active and reactive power balance

Abstract

Previous literature has described non-detection zones where loss-of-mains (LOM) detection is not triggered, such as when the active power imbalance is sufficiently small. This research has tested LOM detection of a commercially available three-phase current source PV inverter in a physical laboratory setting to (a) qualify the size of non-detection zones and (b) to observe the behaviour of the inverter between the islanding event and LOM detection. Results show that islands could be sustained for more than 1500 ms when the active power exchange at the grid connection was below 60 W, or when the reactive power exchange was below 20 VAr. When the reactive power setpoint of the PV inverter compensated for the network reactance, sustained islands could be recreated. The observations can be applied to the formulation of grid codes for operations of small-scale inverter-based generation to ensure that their reactive power setpoints are configured to avoid non-detection zones.