The main objective of this proposal is to conduct a research study towards development of a novel direct current circuit breaker topology which helps in fast and reliable protection of dc grid that eventually boosts in faster adoption of dc grid systems. Direct current (DC) power transmission system renders significant benefits over the conventional ac power transmission systems above a threshold value of transmission distance in terms of reactive power, transmission losses and cost. Additionally, interconnection of dc transmission is very flexible unlike the traditional ac systems wherein synchronization play a vital role. Ever growing energy demand have forced the bulk electric power industry venturing into remote renewable energy resources such as offshore wind power. Power electronic conversion systems such as voltage source converters (VSC) have emerged as the best possible option to realize the bulk power point-to-point/multi-terminal dc systems. However, the principal concern arises from the point of reliability. DC circuit breaker, which is a protection system, remains as the largest obstacle for the adoption of dc power transmission systems. This is due to the absence of natural zero crossing of the current unlike in the ac system. Absence of natural zero crossing of fault current in the dc systems poses several issues, therefore existing high power mechanical circuit breakers which operate on the basis of arc extinguishing using either vacuum or SF6 are capable to clear large fault currents. In addition, dc transmission lines or cables exhibit significantly smaller series inductance which results in a steep rise in fault current in case of an ideal short circuit. Therefore, short circuit current which is flowing through the transmission circuit is only limited by the series resistance of dc transmission line which demands for circuit breakers with very fast interruption time. The critical issue such as faster fault interruption time is partly addressed by development of solid state circuit breakers (MOSFET, IGBT and thyristors). Though solid state CB interrupts the faulty dc sections in a fraction of microseconds, could not successfully replace the conventional mechanical circuit breakers due to the on-state resistance of semiconductor devices which is several order higher compared to the mechanical switches [6 - 13]. This results in substantial conduction loss in the system. Recent developments in high speed mechanical switches have turned the focus towards the hybrid circuit breakers; the major challenge being demagnetization of network inductance after fault current interruption, which demands for energy absorbers such as surge arrestors. These surge arresters again are susceptible to singlepoint failure, which hampers the reliability of the DC system. In this proposal, a hybrid dc circuit breaker without surge arrestors and the precharging circuit is being investigated.