Compatibility study of fuel-cell protective relaying and the local distribution system

The goal of this study was to characterize the compatibility between the protective relaying system of a fully commercialized, 200-kW fuel cell and the local electric power system. This study was motivated by the fact that for several reasons, distribution utility engineers are uncomfortable with the "synthesized" protective relaying and hardware that is generally provided in distributed-generation (DG) systems. This study collected power grid disturbance electrical data and event-related, building-load electrical data over a period of six months. The study dealt with a larger-than-expected number of interruptions to grid-connect power generation. Problems relating primarily to load tracking and also to low power factor, complex load balance dynamics, and possible harmonicdistortion-induced instrumentation error produced some valuable conclusions and several recommendations that would be useful for companies interested in installing a grid-connected DG system.