Analysis Of Thermal Characteristics And Influence Factors Of Heat Dissipation For Enclosed Busbar Trunk Joint Based On Finite Element Method

Enclosed busbar trunk is an important power transmission equipment of the power system,which undertakes the role of transmitting large-capacity current efficiently.Temperature rise has a greater impact on the current-carrying capacity and insulation performance of the busbar trunk for its structure.Compact busbar trunk joint uses insulation boards and fastening bolts to connect,therefore it is not as tightly as the busbar trunk body.When the fastening bolt becomes loose,the contact resistance at the connection area increases,causing the busbar trunk joint to become the area with the most heat and the highest temperature.With the rapid increase in the electricity demand for production and living in China,the current load of the busbar trunk increases and the heat dissipation problem of the busbar trunk joint becomes more serious.Therefore,in order to improve the safety and reliability of the power system,it is necessary to analyze the temperature field of the busbar trunk joint and its influence factors,which can provide a theoretical basis for optimization of joint material and structureFirst,based on the related knowledge of heat transfer,this paper analyzes the structural of enclosed busbar trunk joint and establishes a heat balance equation.The principle of three heat sources and three basic heat transfer methods is analyzed.By comparing the advantages and shortcomings of the finite element software and mathematical method,the finite element software is used to study the temperature field of the enclosed busbar trunk joint.This paper uses finite element software to set up a 3D simulation model,divide mesh and apply boundary conditions of a 1250 A compact busbar trunk joint.Electromagnetic field module is used to calculate and analyze the current density distribution of the busbar trunk joint,whose result is an external heat source in the steady-state temperature field.The temperature field is solved iteratively by the method of pre-estimation and correction and the internal temperature field distribution of the busbar trunk joint is obtained.This paper summarizes the temperature field distribution law of the whole joint,the conductor and the shell,and analyzes the essential reasons of the law.This paper analyzes the influence factors of the heat dissipation in the enclosed busbar trunk joint,and carries out in-depth research from four aspects:busbar trunk load,joint material,external conditions and busbar trunk structure.In each aspect,several influence factors are selected to modify the model parameters.Taking the temperature distribution of the line between left and right shell as the main basis for evaluating the heat dissipation performance,the influence of each factor on the temperature field is analyzed,the essential reasons are further explained,and then an optimization scheme is proposed.Combined with the forced air cooling of isolated enclosed busbar,this paper designs a forced air cooling method for the enclosed busbar trank joint,sets up a mathematical model of forced air cooling,and studies the multiple physical field coupling method.The standard k-s model that meets the actual operation conditions is selected for calculation,the results verify the effectiveness of forced air cooling,and the differences between three air cooling structures on cooling performance are compared.