turbine are connected to the AC grid via fast-acting DC/AC power converters. The battery converter in particular is suitably controlled to permit the operation of the system either interconnected to the LV network (grid-tied), or in stand-alone (island) mode, with a seamless transfer from one mode to the other. Abstract-Within the frame of the European project "Microgrids" several test set-ups have been installed or enlarged at different laboratories. Three of them are presented in this

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... tion: a specially designed single phase system of the NTUA with agent control software, the DeMoTec at ISET, which is a general test site for DER and the flywheel test rig, designed by the University of Manchester. These three sites allow the tests of different components, control strategies and different storage technologies. Though this contribution is aimed at the presentation of the facilities themselves, some test results are included. A. System description The configuration of the microgrid system is shown in Fig. 1 , along with a picture of the actual installation. Index Terms-laboratories, DER, battery inverter, flywheel, wind turbine N. Hatziargyriou, S. Papathanassiou and A. Dimeas are with the