Protection, Control and Automation Requirements for Potential DOD Microgrid Systems

Currently, the majority of the Department of Defense (DOD) facilities (particularly military bases) operate with aging electrical infrastructure that was designed in the 1960s or 70s and since been patched to make it work. The reliability of the overall distribution is generally lower than the utility serving outside the facilities. The aging infrastructures lack consistency and standardization. As the electrical infrastructures become unsustainable (which they will at some point), the DOD will be forced to overhaul them with major system upgrade projects. Recently, DOD and Department of Energy (DOE) also have established various initiatives and task forces to explore feasibility of making DOD facilities more energy independent and secure so that in the event of long-term utility lost they can sustain operations for extended period of time. The best way to accomplish these initiatives is to implement a stable microgrid system in these facilities. As the DOD facilities go through major infrastructure overhaul, integrating microgrid ready design concepts to such upgrade projects would make the DOD smart microgrid systems most practical and cost effective. Majority of the DOD facility load and distribution system is different from the typical utility loads. Typical utility load encompasses a larger geographical area and has various types of loads (such as residential, commercial, and industrial) scattered in different areas. DOD facilities on the other hand have all of the different types of loads in a very close proximity and in smaller scale. In addition, the DOD facilities also have critical and extra-critical loads which need multiple redundancy and backup generation right next to the non-critical loads. In order to implement an effective microgrid at such facilities, the existing infrastructure must be upgraded to a point where every major switching device is intelligent and capable of high-speed communications. On-site generation, high-speed control and protection, effective load-shedding, and system auto-reconfiguration are essential requirements for an effective and sustainable microgrid. This thesis defines microgrid for permanent DOD installations and establishes a representative existing electrical system based on the typical electrical configurations and load characteristics found at the majority of the permanent military installations. Baseline requirements for an installation-wide large-scale microgrid system is defined and a range of component upgrade or system reconfiguration is outlined to meet the microgrid requirements. A representative microgrid-ready system is developed for modelling and technical studies such as load-flow, short-circuit, and on-site generator stability analysis. Based on the results of the studies, key technical challenges and recommended mitigations are outlined for DOD microgrid design considerations. Based on various literature reviews, a conceptual network layout of an example communication architecture for the representative microgrid-ready system is also presented.Thesis (M.Eng., Electrical and Computer Engineering) -- University of Idaho, 201