Intelligent Three Tie Contactor Switch Unit based Protection for Multi-Layered Ring-Bus DC Microgrids

Several types of hidden faults, like arcing and leakage faults along with the short circuit faults, are common in spacecraft power systems. They pose severe challenges threatening the mission success. In this paper, a multi-layered ring bus dc microgrid architecture is used for the design of space exploration vehicle and surface power systems, due to its enhanced reliability of critical loads and high-power density. Layer interconnecting intelligent three tie contactor units (ICUs) are proposed at every microgrid layer interconnecting nodes, which share the status of their contactors with all the local ICUs and source converters in its layer. Using this information, the local ICUs installed at each node in a microgrid layer use a peer-to-peer communication based adaptive protection scheme to detect and quickly isolate any hidden high impedance or short circuit fault in its layer. The proposed protection scheme is tested with the simulation of multiple fault scenarios in the microgrid using the MATLAB model.