The marine closed-loop power grid technology is gradually maturing along with the development of technology. The closed-loop operation of the power grid has the advantages of energy-saving and emission reduction, reduced operation costs and enhanced safety and reliability. It has become the preferred choice for the DP-3 dynamic positioning drilling rig and ships. However, the traditional design of the power protection system cannot meet the requirements of the closed-loop operation of the power grid under DP-3 mode. The faulty switchboard will affect its adjacent sections and the power station does not have the same redundancy and the fault tolerance capabilities as the section operation. Various issues of the closed-loop operation of the power station are analyzed to put forward the corresponding solutions. They can be used as references for the design and operation of the DP-3 closed-loop power system.

This article studies how to rapidly reduce the power grid load and to avoid the under frequency or overload of the other online generators for the dynamic positioning drilling platform in the event of a switch failure trip or the unexpected shutdown of the generator. The fast load shedding strategy based on the events has been introduced and compared with the traditional load shedding method based on frequency and available power on the basis of the platform power station that was equipped with the intelligent electronic device and IEC 61850 communication network. The results show that the fault load shedding strategy based on events has great advantages in rapid response. The fault load shedding strategy based on the events can significantly improve the stability and reliability of the platform power grid for the dynamic positioning drilling platform or ships with power grid using IEC 61850 and GOOSE communication.