Based on DPS-2 multifunctional self-elevating offshore platform real project with a world-leading closed-ring power station, the transient stability analysis method of AC closed-ring power station is described, the test methods, steps and notices for voltage fault ride through are listed, the test contents and result of platform real sea trial are analyzed, and the technology is proven and summarized. This research can not only be used for the projects with equivalent type of independent closed-ring power station or closed-ring power station with dynamic position, but also be used for other projects in offshore engineering, vessels, etc.