الفهرس 
Chapter 1 IntroductionOnly 14 pages are availabe for public view
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Abstract
Planning studies for the design of microgrids (MGs) have been oriented mostly towards conventional AC MGs. However, MGs currently have DC renewable distributed energy resources such as solar photovoltaic (PV) systems, and DC loads such as electric vehicles (EVs) and data centers. In this case, DC generating units are integrated into AC buses through DC-AC converters, while DC loads are connected to AC buses using AC-DC converters. On the other hand, DC MGs require AC generators to be connected to DC buses using AC-DC converters, and AC loads are connected to DC buses via DC-AC converters. It is obvious that the increased number of converters can increase both the power loss and costs. Currently, hybrid AC/DC MGs are gaining more attention to reduce the number of used converters, which can promote the overall efficiency of electrical energy and achieve cost savings.
This work proposes a planning model for hybrid AC/DC MGs to find the appropriate architecture based on both technical and economic aspects. The model decides the type of each bus and line to be AC or DC. The objective of the proposed methodology is to minimize the overall planning expenses, including investment and running costs. The presented model considers line power loss and converter efficiency. The planning problem is formulated as a single non-linear objective problem implemented and solved in MATLAB software. In addition, the uncertainties of the output power of PV systems and wind turbine (WT) generators are considered using a clustering-based method.
The proposed planning model is applied on a MG containing PV systems, WTs, EV charging units, diesel generators, and different AC/DC loads. Several case studies are investigated, where each case is solved by the conventional AC planning approach, the DC planning approach, and the proposed hybrid AC/DC planning approach. The numerical results of different case studies demonstrate the benefits of the presented hybrid AC/DC MGs planning approach. This shows that hybrid AC/DC MGs combine the advantages of both AC and DC MGs. However, the case studies indicate that the effectiveness of the hybrid AC/DC is mainly dependent on the topology of the network and the penetration level of AC and DC components. Accordingly, for each network, planners must compare different planning approaches before deciding which approach to implement.