OPHELIA project: development of MVDC network architecture for large linear photovoltaic farms

Deployment of medium voltage direct current (MVDC) networks is more and more attracted by rapid increase of small-scale distributed energy resources (DER) and fast growth of DC sources and loads. These are typically photovoltaic (PV), hydrogen and battery storage installations, electrical vehicles, data centers and smart buildings. The paper outlines ongoing development of MVDC project for application of linear PV collector network, named “OPHELIA” which has recently started in France. Linear PV is hereby represented by installation of PV panels on a surface that is long and narrow, such as dykes, roads, or towpath, or railway lines. In comparison with traditional installations spreading PV panels over a rectangular shape terrain, linear PV will limit the amount of land used and preserve it for another purpose. To be profitable and operational, the network architecture should rely on a move from AC to DC, exploiting the advantages of DC architecture over long connection of several tens of kilometres, like HVDC. The OPHELIA project targets to develop technological building blocks needed for PV collector networks of multi-megawatt range with nominal voltage up to ±10 kV. Development of converter, cable system, switchgear, monitoring, control and protection will be described. Finally, paper wants to provide experience from a real use case of MVDC and so stimulate standardization work, which is currently missing.