Dynamic power provisioning for cost minimization in islanding micro-grid with renewable energy

Driven by global warming suppression and depletion of fossil fuel resource, micro-grid (MG) especially the one with renewable sources such as solar photovoltaic (PV) and wind generations (WG) are getting attention in power systems. Nevertheless, due to the unpredictability and fluctuation of the energy generated by renewable energy resources, it is hard to adapt to the change of the consumers´ electricity energy demand. Thus, the micro-grid combining the renewable generators and conventional diesel generators will be more reliable to satisfy consumers´ load demand, and the diesel power generation can supplement the lack of renewable power output. However, the use of diesel generators to provide electricity energy is an expensive and environmentally unfriendly way, and dynamically adjusting the diesel energy generation may reduce the fuel cost in micro-grid system. Therefore, this paper considers the problem of dynamic diesel generators reconfiguration for an intelligent hybrid energy micro-grid system which integrates wind generators, solar photovoltaic panels and diesel generators. We conceive a strategy for adjusting the number of the active diesel generators dynamically in order to minimize the total fuel cost while keeping a given quality-of-service (QoS) in terms of shortage probability. By applying the Hoeffding Theorem, we propose a dynamic diesel generators reconfiguration algorithm which is capable of calculating the minimum number of active diesel generators subject to the shortage probability below a desired threshold. Finally, the simulation results show the reduction of the fuel cost.