Finite Element Analysis And Influence Factors Of Heat Dissipation For Discrete Transformer Temperature Field

Transformer is an important equipment of the power system and has been widely used in various fields of power engineering.Temperature changes within the transformer is an important criterion to characterize its safe and stable operation,excessive temperature will reduce the insulation capacity of the transformer,leading to shortened working life.With the development of urbanization and the rapid increase in the use of electricity load,the problem of heat dispersion in transformers becomes more obvious.To solve this problem,underground substations and discrete cooling transformers are often used in many big cities.However,there is little literature on the heat transfer of discrete cooling transformers,therefore it is necessary to study the heat transfer of discrete transformers,establish thermal calculation model and study the influencing factors which can provide evidence for reliable and safe operation of the discrete transformer.Based on heat transfer theory,this paper analyzes the heat source and heat transfer process of discrete transformers,and proposes the thermal decoupling analysis method for discrete transformer.By comparing the advantages and disadvantages of the finite element method,the thermal circuit method and the recommended method,the finite element method was used to study the temperature field of the discrete transformer.This paper uses ANSYS software to set up a 2D model,divide mesh and simulate temperature field of a 35kV discrete transformer,and analyzes in detail the changes of the temperature field of the internal transformer,the temperature distribution of the core and the winding,and the distribution of the oil flow field.By simulating the temperature field distribution of a traditional integrated transformer,the superiority of the discrete transformer in structure and heat dissipation is verified by comparison.This paper analyzes the factors that affect the temperature field of the discrete transformer,and modifies and simulates the model from five aspects:environmental temperature,load factor,horizontal oil duct height of high voltage winding,vertical layout height of radiator and oil pipe diameter.By analyzing the hot spot temperature,the top oil temperature and the temperature difference between the inlet and the outlet of the oil tank,the temperature influencing law is explored,and the relationship between the oil flow velocity and the temperature change is analyzed,and the essential reasons for the influence of various influencing factors on the temperature field of the split transformer are further explained,a layout optimization of discrete transformer is proposed.This paper presents a discrete transformer temperature rise test scheme and sets up an oil-immersed split transformer simulation test platform with different vertical layout heights,the test data and simulation data are compared and the error analysis is performed and the temperature change law in the test is basically consistent with the simulation data.