Laboratory-Based Microgrid Setup for Validating Frequency and Voltage Control in Islanded and Grid-Connected Modes

Small sized synchronous generator based distributed generators (DG) often have low start-up times, and therefore serve as valuable dispatchable generators in a microgrid environment. The advantage is that it allows the power network to operate in a true smart grid environment. The disadvantage is that such DGs typically tend to have low inertia and the prime movers driving these resources need to be controlled in real time for them to operate effectively in islanded, grid-connected modes and during transition. When multiple DGs are present in the microgrid, the overall control can become complicated because of the need for sharing the resources. A smart grid environment is then necessary to control all dispersed generation sources in the microgrid. The most common control strategy adopted for multiple DGs connected to a network is droop control. Droop control ensures that the load needed to be served is shared by all the generators in the network in proportion to their generating capability. Preliminary test results performed on a laboratory microgrid test bench is presented to demonstrate the ability to serve the load at nominal voltage and frequency irrespective of the support received from the main grid.