Research On Temperature Field Test And 3D Simulation Of Oil-immersed Split Cooling Type Transformer

With the continuous development of society,the city's land resources will become increasingly scarce,so the underground substation in the future will gradually occupy the leading position.Since the underground substation in a closed environment,the heat problem is a key factor limiting the development of underground substation.Conventional cooling method of installing heat sink on transformer wall is difficult to satisfy the requirement of underground oil-immersed transformer.Therefore,underground cooling substation adopts cooling mode of body and cooler separately.The research on the underground substation cooling is mainly focused on improving the cooling efficiency and developing new cooling technology.And the split arrangement is rarely involved.The influence of different split arrangement and radiator mounting distance on the temperature distribution of the coiling hot point and the whole equipment is still not clearly defined.The subject based on the study of arrangement of split cooling system structure and the temperature field of transformer,analyzing the influence of different cooling modes on temperature field.This article deeply explores the factors that affect the temperature distribution of the transformer,and fills the gaps in the research field.So the research of this topic can greatly improve the configuration level of the underground substation cooling system and capacity of the cooling,and further optimize the underground substation cooling.This paper combines the related content of oil-immersed transformers on temperature and cooling structure,and the cooling method is studied from the aspects of numerical simulation and equivalent test.By analyzing the mechanism of the transformer's internal losses and calculating the heat dissipation coefficient of the heat sink and other relevant data,the simulation setup conditions are obtained.First of all on a 640 KVA of oil-immersed transformers(cooling: ONAF)split-cooling transformation and split layout based on different ways of temperature rise test for 3 times,measured with a thermocouple and infrared imager data.Based on test equipment and related parameters,by Comsol software to model the three cool test structures,built models imported to the Gambit software and mesh,with Fluent software,using the finite volume method to solve three dimensional simulation model for temperature field and flow field in oil.We also analyses of three separate cooling layout for winding hot spot temperature and the overall effect of temperature distribution and flow field.This research shows that the center height of radiator of miniature oil-immersed transformer improves 2 meters,while the hot-spot temperature declines to 8k.Horizontal distance between radiator and transformer shrinks 3.5m,while the hot-spot temperature declines 4k.Winding hot spot position at the end of the winding distance from the lower end of the 75%-80%.After the comparisons of experimental data and simulation data,we have gained important date that relative error is within +6%,which has verified accuracy of stimulation model and engineering practicability.After the validation of above data,this paper further analyzes the impact that the up and down split cooling arrangements have on coiling hot spot temperature through simulation models.By combining with the above conclusions,it provides some technical supports to formulate standards for cooling project of urban substation split cooling system.And it also perfects the study for the installation of split cooling methods to underground substations.