A Method for Determining Ampacity and Temperature Field of Submarine Cable

Abstract

The invention discloses a method for determining the ampacity and temperature field of a submarine cable, which comprises the following steps: (1) determining the soil temperature sensing area in the two-dimensional plane where the cable cross section is located; (2) performing a finite element network on the soil temperature sensing area The finite element triangular network is obtained by lattice subdivision, and then the nodes in the finite element triangular network are numbered; (3) The stiffness coefficient and internal heat coefficient of each triangular element in the finite element triangular network are calculated according to the cable current; (4) According to the stiffness Coefficient and internal heat coefficient, the temperature field model is established through the finite element overall synthesis as follows: KT = P; solve the temperature field T; (5) determine the temperature field T according to the maximum working temperature of the cable core conductor max And substituting it into the temperature field model as the target vector to solve the current carrying capacity of the cable. The invention can flexibly simulate complex boundary conditions and environmental parameters, and is closer to the actual operating conditions of cables than the prior art, and can obtain more accurate results.

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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