A Techno-Economic Sizing Approach for Medium-Low Voltage DC Distribution System

DC distribution system (DCDS) has many preferable advantages to integrate renewable energy sources and native-DC loads than AC distribution system (ACDS), and the benefits of higher power density, greater energy conversion and wider supply radius can be obtained. In this paper, a methodology of sizing the techno-economic of a medium-low voltage DCDS is proposed. Firstly, the system framework and its equipment composition are stated. Then, considering the distribution capacity, supply ability, operation loss and reliability, the technical indicators of the demonstrated DCDS are analyzed and quantified. In regards to the DCDS's distribution-level and consumer-level, the calculation models of the annual costs are presented. Further, different scenarios are imitated to verify the efficacy of the proposed sizing approach, and the techno-economic comparison is implemented in the DCDS and ACDS with similar structure configurations. The calculation results reveal that the DCDS shows a visible economic performance at the consumer-level, and for the scenario of accessing high proportion DC loads, it is more cost-effective than the ACDS. Finally, the correctness of the cost models is proven, and this study can offer a reliable reference for building the medium-low voltage DCDS.