This report deals with the analysis of ''islanded'' operation in electric utility-connected, residential photovoltaic systems. Islanding is a phenomenon in which several such systems continue to operate and, together, keep the electric distribution system energized even after the primary source is disconnected. Such operation presents a hazard to utility and other personnel. We show how islanding can be studied using a combination of a power-flow- analysis-like method, an examination of large-signal limit-cycle behavior, and small-angle stability analysis that can account for control system response. The methodology is validated to a limited extent through simulation and testing. Studies conducted using the developed methods suggest that, although islanding is intrinsic to all systems, normal load variation, inverter protective mechanisms, voltage/frequency relays, and destabilizing feedback controls effectively limit the practical possibility of islanding. 14 refs., 63 figs., 2 tabs.