TRANSITION FROM GRID-CONNECTED TO ISLANDED DROOPED MICROGRID BASED ON ISLANDING DETECTION SCHEME

The principle of microgrid operation entails that it should be able to operate either grid-connected or isolated in island mode in case of grid disturbances. A microgrid is generally composed of distributed generators (DGs) connected to the main utility grid, usually through controlled voltage source converters. P/V and Q/f droop control technique is presented in this article to develop the microgrid performance during grid-connected and islanded operation mode. This droop control technique can perform efficiently for active power sharing of the microgrid load demand. By implementing the control strategies on the control units of DGs voltage source inverters, the microgrid generating units can actively transfer desired real power to the local loads. Implementation of islanding detection scheme to switch the control mode of each DG inverter is also another contribution in this article. The effectiveness of the proposed islanding detection scheme and droop control strategy has been validated through simulations using SimPowerSystems toolbox of MATLAB/Simulink.