Load Support by Droop-Controlled Distributed Generations

Due to the proliferation of distributed generations (DGs), the issue of cooperating them with already existed synchronous generators (SGs) in power grids should be considered and analyzed adequately. Concerning the slow response behavior of SGs, large load changes cannot be quickly compensated by them, resulting in significant deviations in their frequencies. In such circumstances, grid-supporting DGs with flexible and fast response behavior is a smart solution for compensating the load changes. However, the grid-supporting DGs with the conventional droop control mechanism is not able to provide the load support promptly. This drawback of the conventional droop control method has been distinguished as the tardy load support problem. In this article, a variable coefficient droop control method is proposed to solve this problem. The variable coefficient droop control activates its variable droop coefficient mode so that DGs can support load changes timely in the presence of heavy disturbances. The tardy load support problem and the proposed variable coefficient droop control method are theoretically analyzed. The simulation and hardware-in-the-loop experimental results both verify the effectiveness of the proposed variable coefficient droop control method.