High-voltage submarine power cables in service

subject to ocean currents for a long time

may produce mechanical fatigue failure due to vortex vibration

threatening the operational stability of submarine power transmission. Therefore

it is necessary to study the response of vortex vibration of the cable and its fatigue evaluation method in different marine environments. In this paper

based on the ±400 kV flexible DC transmission cable supporting Rudong offshore wind farm

based on MATLAB

the finite element method is used to analyze its eddy-excitation vibration characteristics under different seawater flow rates

different lengths of suspended segments

and different seawater temperatures

as well as its fatigue state evaluation after vibration. And the line shape of the suspended span section of the submarine cable obtained from the simulation is compared with the theoretical calculation value. The error is 0.16%

which verifies the accuracy of the simulation model. It is concluded that

when the seawater flow rate increases

the vibration amplitude of the cable increases

and the amplitude reaches the maximum value when the excitation frequency and the intrinsic frequency are the same

moreover

the vibration amplitude decreases when the flow rate increases again; when the length of the cable overhanging section increases in the range of 0~30 m

the vibration amplitude increases and the amplitude is maximum at the time of resonance. The resonance amplitudes at each overhang length have the same trend

and all produce amplitude maxima at the center; when the seawater temperature changes within the normal range

the impact on the vibration amplitude of the cable is in the millimeter level

and the vibration amplitude is in the millimeter level. It can be approximated that the seawater temperature does not affect the vibration amplitude of the cable. The fatigue life of the armor layer and the alloy lead jacket layer of the submarine cable was studied and analyzed. The results show that there is no fatigue damage to the armor layer even under resonance conditions

and it can be assumed that no fatigue damage occurs to the armor layer; for the alloy lead jacket

the fatigue life is about 65.45 years with a seawater flow rate of Lianyungang(a city in China) route and an overhanging section of 25 m.