Impact of Grounding on Overcurrents for a Naval AC/DC Shipboard Power System

DC faults can have a detrimental impact toward the system dynamics of a small-scale DC distribution system. Future naval combat ships employing a DC distribution systematic layout require a protection method that is significantly fast and intelligent in its decision making process in analyzing faults. The DC distribution system must be able to withstand and tolerate malicious DC faults for a certain period of time if sensitivity is a factor in the fault analyzing process. When a DC fault strikes the DC distribution network, it can almost instantaneously cause overcurrents to spike providing a heavy blow towards normal system operation. This research is geared at the possibility of employing a 12-pulse low or medium voltage DC converter into future naval combat ship systems. The study also employs the use of passive filtering technique to reduce harmonic order on the naval ship for power quality purposes. In order to reduce overcurrents to minimize systematic damage during a DC fault towards the DC distribution network, grounding schemes have been analyzed in this paper to find various methods to reduce the problem. The harmonic tuning filters are also analyzed during the DC fault to examine their effect or contribution toward an overcurrent during a DC fault.