| Power switch cabinet is the basic component of power system,which undertakes the task of power transmission and distribution.On the one hand,the power loss will increase,if the busbar temperature is high.on the other hand,fire and other safety accidents which will cause negative social impact and economic loss,will occur,Forthermore,it endangers the power grid safe and stable operation of the power grid.Therefore,in order to reduce the temperature in the power switch cabinet,it is necessary to predict the distribution of the temperature field distribution of the power switch cabinet,And then,some effective measures,which can strengthen the heat dissipation capacity of the power switch cabinet,can be put forward according to the distribution characteristics of the temperature field of the power switch cabinet.This paper has been established three-dimensional heat flow coupled thermal analysis model based on the heat transfer process of power switch cabinet.According to the distribution characteristics of temperature field and speed field of power switch cabinet,the influencing factors analysis and heat dissipation performance evaluation of busbar in power switch cabinet has also been analyzed,Then,three-phase busbar layout optimization is carried out,this research can provides theoretical basis in power switch cabinet temperature field prediction and cooling measures.The main research work is shown as follows:(1)Based on the heat transfer characteristics of power switch cabinet,a three-dimensional heat flow coupling model is established by using finite volume method to solve the temperature field and velocity field in consideration of convection and radiation.Because the data transfer between temperature field has been realized,the temperature error caused by convection heat transfer coefficient on busbar surface is reduced.(2)Based on the above research characteristics,design the temperature rise experiment platform of the power switchgear,and carry out the temperature rise experiment of the power switchgear busbar.by comparing and analyzing the traditional engineering algorithm for solving the temperature field of power switchgear,the heat-fluid coupling algorithm established in the article and the experimental test method,it is found that the maximum error of the solution result of the heat-fluid coupling model established in this paper is 3.1%,while the minimum error of the traditional engineering algorithm is 12.1%.The correctness and accuracy of the heat-fluid coupling model established in this paper are verified,and the irrationality of ignoring the radiation effect of the power switchgear is also proved.(3)Based on the three-dimensional thermal flow coupling model of the power switch cabinet,the influence of the above factors on the heat dissipation of the power switchgear cabinet is analyzed from the external environment(such as load current,ambient temperature,atmospheric pressure and wind speed at the inlet of ventilation)and the structure of the power switch cabinet(such as busbar height,spacing,deflection angle,dislocation,vent position and area).Combined with orthogonal method,the influence of external environment and power switchgear structure on the average temperature rise of busbar surface is sorted.The results show that the importance of the factors influencing the average temperature rise of phase B busbar in the power switchgear cabinet is shown as follows: wind speed at the inlet of ventilation > load current > ambient temperature >atmospheric pressure;and the influence factors of the structure factors of the power switch cabinet on the average temperature rise of the B-phase busbar surface is shown as follows:relative height of busbar> horizontal distance of busbar > busbar vertical spacing > deflection angle of busbar > Ventilation inlet and outlet area ratio>ventilation inlet and outlet offset.(4)Combining the obtained heat dissipation factors that have a significant effect on the average temperature rise of the busbar in the power switch cabinet,taking the ventilation inlet wind speed,the horizontal spacing of the busbar,the vertical spacing of the busbar and the deflection angle of the busbar as the design factors,the response surface method and the BP neural network are constructed respectively.An optimization model of busbar layout combined with genetic algorithm.By comparing the results of the model solution before optimization and the experimental test values after optimization,the application scenarios of the two methods are obtained.The BP neural network combined with the genetic algorithm is more suitable for solving problems with strong nonlinear relationships than the response surface method.To solve the busbar layout in the cabinet,if you pay more attention to the heat dissipation capacity of the busbar,you can choose the BP neural network combined with the genetic algorithm to optimize.If you pay more attention to the cost,you can choose the response surface method to optimize.At the same time,in order to analyze the heat dissipation capacity of the busbar,based on the non-dimensional analysis method,the relative temperature rise proportion was introduced to evaluate and predict the heat dissipation performance of the busbar in the power switch cabinet. |
PDF Full Text Request