Research On Design Techniques Of Offshore Wind Power Cable Bending Protection Device

Submarine cable is one of the key equipment for offshore wind farm development.In order to prevent the damage of the submarine cable near the pile foundation in place,it is necessary to use bending protection device to bend the submarine cable.At present,China's bending protection industry is in its infancy,it is necessary to grasp the design technology of bending protection devices as soon as possible.The main functional units of the bending protection device are the curving,bending,and a new type of bending protection unit(hereinafter referred to as the new type of casing)which is used to fuse the bending device with the casing.The principle of bend restrictor,bend stiffener,and bushing is to control the curvature of the submarine cable by increasing the bending stiffness,but there are also some differences.In this paper,the design methods of the main function unit,the bend restrictor,the bend stiffener and the new bushing are also studied.This paper first summarizes the technology of submarine cable bending protection.Through the analysis of the working condition of the fixed wind power pile based sea cable in shallow sea,it is confirmed that the bending failure may occur during the operation process of the submarine cable.By analyzing the failure mode of the bending protection device and the submarine cable,the design criteria of the bending protection device are determined.The key performance indexes of bend restrictor,such as combined bending stiffness,locking radius,bending protect length,strength,design method and design process of bend restrictor,are put forward,and the design of bend restrictor is completed.The load of the submarine cable under the action of the bend stiffness is analyzed and calculated.The preliminary design of the bend stiffener is completed by using the theory of large deformation and variable cross section beam to write the fast design software of bend stiffener,and the reliability of the design of the bend stiffener is verified by the finite element model.In view of the working principle of the bushing,the key performance indexes of the bushing,bending stiffness and length,are put forward,and the design of the key performance indexes of the bushing is completed by means of the cable type analysis.The guiding opinions of the selection of the bushing material are given.Finally,the design of the new type of bushing is completed with the same method,and the new type of bushing has been proved to be new.The new bushing has better bending protection than the old one.Through the work of this paper,the research on the design technology of the cable bending protection device near the shallow sea wind pile foundation is preliminarily completed,which has some reference significance for the engineering application of the bending protection device.