An increasing amount of consumer devices and end-use applications of electricity at the low voltage level that require a direct current (DC) power source have continued to advance in modern day society. At the same time the existing alternating current (AC) infrastructure that has served so well over the past century is beginning to show its age and vulnerability, leading to increased outages and reduced reliability. Also, the amount of high voltage direct current (HVDC) transmission system installations continue to increase around the world because of their proven superiority to high voltage alternating current (HVAC) in certain scenarios. However, with the widespread development and maturation in recent years of low voltage DC devices and systems, as well as large scale HVDC systems, no DC-based infrastructure or delivery system exists to efficiently connect the two together. Such an infrastructure would be developed through a medium voltage DC (MVDC) architecture. In order to properly analyze the benefits of a MVDC infrastructure for power distribution networks, a comparison between MVDC and MVAC architectures is necessary to identify advantages and disadvantages of both approaches. Investigating an architecture that would supply DC power to loads that is not much different in function to the existing AC grid system used today may bring with it increased efficiencies, therefore leading to economic operational and reliability benefits. To the author's knowledge, this thesis provides the first system scale comparative analysis of this nature comparing MVAC and MVDC. The preliminary design for such a system to supply DC power was created in this thesis using the PSCAD software package. The system analyzed utilizes a medium voltage DC bus rated at 20kV with a set of interconnected loads and generation. The DC system, while complicated with its wide array of power electronic converters, grants the ability to control power flow into the system from the different generation sources and to the loads. While the infrastructure design created is an initial step for a larger system, it lays the foundation for the future development of a DC distribution system for real world applications.
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