Study on the Behavior of 220 kV Three-Core Submarine Cable with a Suspension Span of 1.6 m Scoured by Current

Due to the complex submarine environment, submarine cables are prone to be partially exposed or even suspended. The suspended span section of the submarine cable is disturbed by the repeated scouring of ocean currents, which can easily lead to fatigue of the submarine cable and even cause electrical faults. At present, submarine cables usually use distributed optical fiber sensing technology for condition monitoring, so it is necessary to study the force of submarine cables under ocean currents for submarine cable operation and maintenance and fault warning. Based on this, we establish a three-dimensional finite element simulation model of the 220 kV optical fiber composite submarine cable with a suspension span length of 1.6 m and study the stress of the submarine cable in the suspension span section under the current scour in the paper. The natural frequency of model vibration is obtained through modal analysis. The scour of the submarine cable is simulated and analyzed using the fluid-structure coupling method. The stress and displacement distribution of the submarine cable armour layer and the optical fiber are obtained. The frequencies of optical fiber vibration are obtained through Fourier analysis of the lift coefficient. The results show that the stress and displacement of the submarine cable armour layer and optical fiber are symmetrically distributed, with the maximum stress and displacement at both ends. The vibration frequency of optical fiber is mainly concentrated at 0.6 Hz and 1.6 Hz. This study provides a theoretical reference for monitoring the working state of submarine cables with short suspension spans using distributed optical fiber vibration sensing technology.