The electric topological structure of a hybrid offshore renewable energy generation system, including offshore wind, wave, and tidal power generations, is described. Using this system as an example, a detailed model and phasor model based on the Matlab/Simulink platform were built. On the basis of a qualitative analysis of the differences in these two models, simulations were carried out with different wind speeds and power grid disturbance faults. Timedomain simulation results show that the tendency of steady and dynamic responses of the detailed model and phasor model are similar; the simulation time is longer when using the detailed model, and the simulation curves contain highfrequency components; and, with the phasor model, the simulation time is shorter, and the simulation curves are relatively smooth.