FLEXIBLE FREQUENCY CONTROL STRATEGY FOR ISLANDED MODE MICRO GRID

Today, several types of DGs are connected together and formed a small power system called micro-grid (MG). MG is connected to the primary distribution network and usually operates under the normal mode. All these micro sources are connected to the Micro Grid through inverters except the wind generation system. The inverters are modeled under two control strategies. The first strategy is performed under the PQ control which established with the inverter will inject a certain active and reactive powers. The above type of inverter is used to interface over droop control. This model is used to interact in flywheel will act as the reference bus. Dual process have been performed, the first issue is about the effect of islanding operation on frequency, in this the voltage and active power presented around MG obtain active and reactive power from the primary distribution network. The next operation explains about the effect of islanding like a feedback from previous values. So MG delivers active and reactive power to the same primary distribution section now. This will results in the storage device (flywheel) with an complete control on inverter, which can maintain the frequency of the MG and also the voltages represented in all buses around their limited levels.