Simulation Study On Temperature Field Of 10kV Three-core Power Cable Joint

Cable intermediate joint is a weak link in the operation of cable line with many accidents.It is of great significance to study the heat transfer mechanism of cable intermediate joint,determine its temperature field distribution,and accurately calculate the carrying capacity to ensure the safety of cable intermediate joint and improve the overall reliability of cable line.In this paper,the structure and composition of 10kV three-core power cable commonly used in distribution network are described in detail,as well as the classification and heating mechanism of cable joints.The calculation method of cable loss and the analysis of heat transfer process are introduced,providing theoretical basis for the numerical calculation of cable temperature field.The basis of finite element calculation of heat transfer is heat conduction,heat convection and heat radiation.On the basis of this paper,by using ANSYS finite element analysis software established 10 kV three core cable joint electromagnetic-thermal coupling calculation model,and a calculation example is given.Compare the cable joint section temperature field and temperature field distribution of ontology cable results under the same conditions,then,the accuracy of the model is verified by field measurement.Then,by setting the contact resistance coefficient k of the connector conductor,the temperature field calculation model of the cable connector that takes the contact resistance into account is established,and the temperature characteristic distribution rule of the cable connector when the contact resistance of the connector conductor is too large is studied.With the increase of the contact resistance,the temperature of the cable core and the surface of the cable connector gradually increases.Based on the distribution of temperature characteristics,the characteristic quantities of joint contact resistivity k were extracted.Finally,the representation method of k value is obtained by function fitting.In the end,based on the research of characterizing k and contact resistance simulation model,the calculation method of cable current-carrying capacity considering cable joints is proposed,and the results of numerical calculation method and thermal path analysis method are compared.Finally,the influence of ambient temperature on cable carrying capacity is analyzed.