Investigation on the system grounding types for low voltage direct current systems

The advantages of low-voltage direct current (LVDC) distribution power systems are emerging with the proliferation of distributed generators and power electronic devices. In comparison with the existing LVDC application in telecommunication, vehicle, ship and traction systems, LVDC distribution power systems concern more protection for safety, especially protection against electric shock caused by indirect contact, since they are widely utilized at non-professional places. This paper compared the touch voltage limits of LVDC systems with those of low voltage AC (LVAC) systems, and analyzed the safety of LVDC systems with various grounding types when a grounding fault occurs. The simulation results for the LVDC systems with different AC/DC interfaces were also presented and compared.