The closed bus-site power system has been increasingly used in the design of the power station on the dynamically positioned vessel for the energy conservation and emission reduction during their operation. The design and inspection requirements of the closed bus-tie power system are put forward in the rules or guidelines of ABS, DNV-GL, CCS and other classification societies. Among them, the low-voltage fault ride through capability is one of the key points in the reliability assessment of the closed bus-tie power system by the classification societies. The design points of the fault ride through the function are analyzed from the requirements of the closed bus-tie power system by the classification societies, combining with the numerical simulation experiment. On this basis, the implementation of the fault ride through the function is explored.