Transient Stability Enhancement in Microgrids Including Inverter Interfaced Distributed Generations

With increasing the presence of Microgrids (MGs) in the power systems, investigating the MG stability during transient faults is necessary. This study investigates the transient stability analysis of a MG supplied by multiple inverter interfaced distributed generations (IIDGs) during fault. The transient stability of a MG is highly depends on the IIDGs control strategy. A MG, simulated on Matlab/Simulink, including three IIDGs and two local loads connected to the IEEE 37-node distribution system is considered as test system. Simulation results show that the MG may lose its stability due to the IIDG’s transient over-currents during fault. By adding a transient current control loop to the voltage source inverter (VSI) control strategy, the IIDG’s output currents are limited during fault. In the connected mode, an external fault is applied to the MG. By using an appropriate tuning based on fuzzy logic method, the transient loop controller coefficients is optimally tuned. The simulations results show the good performance and fast dynamic of the proposed control approach; also the transient stability enhancement of the MG, obviously.