Optimization of grid connected micro-grid consisting of PV/FC/UC with considered frequency control

In this paper, ultracapacitors are used as short-term storages for the frequency control of grid-connected microgrid that consists of photovoltaic panels, fuel cells, and the battery packs as long-term storages. Fuel cells and battery packs have delays in load tracking; therefore, ultracapacitors are used to compensate for the sudden power fluctuations in the microgrid that occur due to the output power uncertainty of the PV arrays and the loads required in the microgrid, as well as the sudden interruption of the main grid. The microgrid consists of interruptible and uninterruptible loads. When the total produced power in the microgrid, in addition to the purchased power from the grid, cannot satisfy the demand, first, the interruptible loads, and then the uninterruptible loads, are interrupted. In this paper, the forced outage rate of each component and some notions of the reliability are considered for the microgrid. To ensure the system's reliability, the uncertainty of the PV power and load demand is considered.