Method for determining carrying capacity and temperature field of submarine cable

Abstract

The invention discloses a method for determining the carrying capacity and a temperature field of a submarine cable. The method includes the following steps of firstly, determining a soil temperature sensing area of the cross section of the cable in a two-dimensional plane; secondly, conducting finite element mesh generation on the soil temperature sensing area to obtain a finite element triangular network, and numbering all nodes in the finite element triangular network; thirdly, calculating the rigidity coefficient and the internal thermal coefficient of each triangular unit in the finite element triangular network according to the current of the cable; fourthly, setting up a temperature field model, namely, KT=P, through finite element overall synthesis according to the rigidity coefficient and the internal thermal coefficient, and conducting solving to obtain the temperature field T; fifthly, determining the temperature field Tmax according to the highest working temperature of a cable core conductor, substituting the temperature field Tmax to the temperature field model to serve as a target vector, and conducting solving to obtain the carrying capacity of the cable. According to the method, complex boundary conditions and environment parameters can be flexibly simulated, compared with the prior art, the method is closer to the practical running condition of the cable, and a more accurate result can be obtained.

Description

technical field [0001] The invention relates to the technical field of power cables, in particular to a method for determining the ampacity and temperature field of a submarine cable. Background technique [0002] With the continuous development of the national economy and the construction and transformation of urban and rural power grids, the number of power cables laid is increasing day by day. In coastal and offshore areas, the limitation of natural conditions such as terrain has caused the inconvenience of laying overhead lines, thus greatly improving these areas. Dependency of power grid development on cables. [0003] The ampacity is an important electrical parameter in cable operation. The current flowing through the cable core is higher than the rated ampacity, which will lead to excessively high operating temperature of the cable, aging of the cable insulation, and greatly shortened cable life. One of the most important jobs in . [0004] The calculation of cable ...

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Problems solved by technology

[0005] This standard is calculated under the assumption that the cable load rate is 100%, the soil and the cable surface are isothermal surfaces, and the cable layers are equivalent to concentrated thermal resistance parameters. However, in actual operation, each layer of the cable is not an ideal isothermal surface. It also changes with time. When there is a large deviation between these actual working conditions and the assumptions in the standard, there must be errors in the calculation results that cannot be ignored.

[0006] The determination of the ampacity of submarine cables requires separate calculations for the seabed, tidal flats, and landing sections of the submarine cable. The IEC series of standards mainly reflect the differences in the environments of the seabed, tidal flats, and landing sections through the correction of external thermal resistance. In actual operation, cables and The heat conduction of soil and the heat exchange between soil and seawater or air are very complicated, and the external environment is simulated by a thermal resistance, which cannot accurately represent the temperature field of the cable and its vicinity

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