Dynamic Overcurrent Saturation of Distributed Sources in a DC Microgrid System

Due to the advancement of microgrids, the electrical distribution network is transforming rapidly. The close proximity of distributed generations, loads and widespread use of power electronic converters have brought enormous flexibility and controllability to the distribution system. The transient studies of dc microgrid need more attention to ensure stable and reliable operation of the converters. One of the important phenomena is overloading of a source converter during a large load transient. The source current may increase due to the large increase in load connected to its proximity. Conventionally this issue is addressed by using a static current limit, which protects the converters. However, this leads to significant disturbances in the system, especially when this converter recovers from saturation due to other converters sharing the load. A suitable dynamic overcurrent saturation technique, proposed in this paper is advantageous over the existing constant current saturation method. This paper shows a detailed procedure of determining the dynamic current limit and its implementation in the controller in line with the device manufacturers' guidelines for the enhanced operating condition in dc microgrid.