Abstract: This study examines the role that a storage system of AC, plays, micro-grid frequency control. Micro-grid study is part of a network of radial distribution, medium voltage and contains 2 types of DG units, gas units and a photovoltaic unit. Depending on the type of production units is used in micro-grid? So, dynamical behavior micro-grid, using a storage system AC and a primary control of frequency and voltage change in a manner that requires loads sensitive within micro-grid met. Two different scenarios in the form of unplanned island and the deliberate Island have been considered as micro-grid response to the applied perturbation is investigated. Finally, micro-grid dynamic behavior, compared with the case where micro-grid no reserve system is AC. Simulation results show that the storage system and its control scheme as well is accountable to the standards required, AC for sensitive loads.