Operation of Distributed Generation in Weak Grids with Local Critical Load

The integration of distributed generation (DG) in weak grids can help the utility in providing reliable power to critical and sensitive loads. That requires the modification of the DG controller to be able to continuously supply power to the loads that are connected at the same bus. In this paper, an algorithm has been developed to ensure the continuous and proper operation of a DG either in case of grid power existence or grid outage. In normal operation, the DG is capable of supplying power into the grid and maintaining the nominal voltage. Moreover, the DG controller, in case of grid failure, is capable of maintaining the nominal values of both the voltage and the frequency. The transients due to the transition between the two modes are discussed