DC Grid Design

Abstract

This thesis covers the top­level design of a DC microgrid of a tiny house community on the roof ofa high­rise building in Rotterdam. This DC microgrid consists of 12 tiny houses, a common usagearea, Renewable Energy Supply (RES) methods, using solar and wind energy, and an Energy Storagesystem (ESS). This design is part of a complete DC smart grid for such a community with two othersubgroups focusing on the control and software, theCNSgroup, and power line communication, thePLCgroup.In this thesis, three design phases are discussed; demand estimation, storage & supply design, andtopology design. Subsequently, the resulting grid design is validated. The first phase resulted in anestimation of hourly, daily, and monthly energy usage. Using a model of the generation, 61.2푚2Photo­Voltaic (PV) panels and 6 Vertical Axis Wind Turbines (VAWT)s were selected. In order to handle thevarying energy generation of theRESs, differentESSoptions are considered, and 4 Li­Ion batteriesare chosen. This combination of storage and supply resulted in a grid availability of 93.73%. In thelast design phase, the topology of the community is designed, which resulted in a 400 VDC unipolar ring-­based series­ connected multi­bus configuration, which effectively operates in radial form to re­duce complexity and enables easier fault location detection. The topology design also considers theconverter requirements, wiring, and stability and safety considerations. A cost analysis is made ofthe entire grid resulting in an estimated total cost of around €100,000. Lastly, design verification isperformed on the proposed design, which resulted in functional results during 100% demand, with amaximum voltage drop of 1.82% and during 150% demand, with a maximum voltage drop of 2.80%.