Design of a Bipolar DC Grid Fault Emulator

DC grids offer many advantages in terms of efficiency, cost and ease of implementation. The protection of these grids, however, still raises many questions. Furthermore, no standardized testing procedures for testing low voltage DC grid protection systems exist. This paper proposes the design for a fault emulator capable of creating consistent faults in low voltage bipolar DC grids. The use of a fault emulator aids in the design of DC grid protection systems and supplements DC grid simulations as not all phenomena are visible in simulations. First, an overview of the design considerations is given followed by an overview of the topology. Tests are conducted determining a set of specifications for the fault emulator. Finally, a fault will be created and an explanation of the DC grid fault behavior is given.