MVDC Distribution Grids and Potential Applications: Future Trends and Protection Challenges

This paper presents the fundamental system components of medium-voltage direct current (MVDC) grids, including an overview of power electronic converters and protection schemes against DC fault currents. In addition to this, the lack of standardization and the development of efficient and reliable circuit breakers (CBs), which are today considered as showstoppers, are also analyzed in detail. The performances of three DC CBs, namely mechanical breaker with active current injection, solid state CB and hybrid CB are evaluated in terms of clearance times, fault peak current, residual energy dissipation and power losses using simulations. Last but not least, an overview of potential onshore and offshore future applications of MVDC grids is also presented by identifying targeted voltage and power ratings.