Challenges and Solutions in Modern DC Grids Part 1: Architecture and Definitions

This paper gives an overview of possible architectures and definitions for future DC Grids. The differences between the DC Grid and AC Grid are explained in terms of the radial, ring or meshed structure. The advantage of bipolar grids and the reduction of cable weight is discussed. Arguments are given for a recognizable color for the DC cables for both bipolar and unipolar systems. A proposal is done for a voltage level, to meet the requirements in industry, utility, but also to comply with existing IEC normalization regarding maximum voltage levels. Zones where the level of safety is defined by the type of protection, are proposed.