A powerful and efficient power transmission network is urgently required to support offshore renewable energy harvesting. To promote the development of submarine superconducting power cables, it is essential to investigate the influence of partial dysfunctions on the supercondncting power cable, especially to its AC loss characteristics. It is possible that the partial dysfunctions can cause fast and massive increase of losses in the form of heat, and consequently break the cryogenic thermal stability and drive cables out of superconducting state. Based on underground cables, numerical models are developed to simulate monolayer and multilayer submarine superconducting cables. Currernt and magnetic field distributions and AC losses are analyzed via Finite Element Method(FEM). Results show that AC losses of monolayer and two-layer cables increase dramatically with a single superconductor tape damaged, while AC loss of six-layer cables exhibits an increase of less than 5%. This makes six-layer superconducting cables more suitable for developing superconducting power networks within marine environments.