Under an outage condition, a DG system that is still producing and is still connected to the grid can create an electric “island”, supplying power to single or multiple services within proximity of the facility. This can be a significant safety hazard to line crews troubleshooting outages and restoring power.
YVEA requires that a Qualifying Facility have anti-islanding capability and a lockable AC disconnect, in order to maintain complete control of the grid during such events. In the case of an inverter, this capability is part of the control software for the device. The data sheet should specify whether the device has such capability.