It is known that nearby lightning strikes can induce overvoltages in photovoltaic arrays. However, although many laboratory studies have been reported, relatively few field studies have appeared in the literature. This paper reports on a field study conducted at South Dakota State University and the Florida Solar Energy Center in which a high-speed datalogger was used to monitor the voltage at the terminals of two photovoltaic arrays. The design of the datalogger is described, and its measurements are given and discussed. Two important conclusions were reached: one, that the field measurements seem consistent with laboratory measurements and suggest that DC-side protection for PV power electronics is important; and two, that it is not always possible to tell from anecdotal observations whether a lightning storm is dangerous for PV power electronics.

Investigators at South Dakota State University and the Florida Solar Energy Center installed a high-speed datalogger on a high-voltage PV series string as part of an experiment to quantify lightning-induced transients in PV arrays. However, during the measurement period, an unexpected result was observed: large voltage spikes appeared at the PV array terminals during the inverter's morning start-up and evening shut-down procedures. This paper describes those observations, probable causes and effects, and mitigation options.

As work continues on synchronizing anti-islanding standards worldwide, disagreement remains as to whether it is necessary to include motors in the loads used in the tests. One reason is that there is still a lack of a full physical understanding of the behavior of motor loads in islands. This paper explores the behavior of single-phase induction motors in islands and proposes a theory to explain the available observations. The use of parallel RLC loads to adequately model motors for islanding tests is discussed. Finally, the appropriateness of including a motor acting as a flywheel is questioned