A Center-Free Control Strategy for the Coordination of Multiple Photovoltaic Generators

Coordinated regulation for the outputs from renewable energy sources is an appealing issue in future smart grid. This paper presents a distributed control strategy for multiple photovoltaic generators (PVs), which makes all the PVs have the same reserve ratio with respect to their maximum available power, but also makes their aggregated output support power network by providing power regulation service within the power limit. In addition, an estimation method is proposed to get the maximum available power of PV. The proposed control strategy is nearly center-free, i.e., there is no centralized station which collects the output of each PV and sends the power command to each PV, and only uses local communication networks (CNs) to avoid expensive sometimes unreliable, long distance communications. Simulation results based on the IEEE standard 123-bus distribution system are presented and discussed, illustrating the effectiveness of the proposed control strategy.