Study Of The Unsteady Temperature Response For Large Natural Oil Transformer With Directed Structure On Overload

Today the transformer which STATE GRID used is most of oil-immersed tra-nsformers,because they have good coolant,low wastage and large capacity.oil-i mmersed transformers are mainly forced oil circulation transformers and natural oi-l circulation transformers.Because the forced oil transformers have the problem of noise-disturbing-citizen problem and the static electricity in oil flow,so recent years forced oil transformers has turning to be natural oil transformers.The result of adopting natural oil circulation is to increase the temperature difference betwe-en copper and oil.So the heat elimination becomes more serious.In this paper,the corresponding mathematical model and physical model are established based on the knowledge of heat transfer and fluid mechanics,and finishing the calculation of the unsteady temperature difference for large natural oil transformer with directed structure on overload.In order to design the transformers and realize the power grid integration we use it to provide a reliable data for the monitoring of transformer networking.At the same time,it also helps to improve the structural design of the transformer.In this paper,the method of balancing the total drag and buoyancy lift is used to solve the oil flow quality.And according to the oil flow,the average oil temperature rise is determined by the external heat transfer.In this paper,the software of unsteady temperature response for large natural oil transformer with directed structure on overload is compiled,which has friendly and beautiful interface,the interface parameter name is also more professional,and is easy to master the relevant engineering and technical personnel.In order to verify the correctness of the results obtained by the software,the result which calculated by the software is verified with the experiment data and the Loading guide for oil-immersed power transformers.The results show that the physical model and the mathematical model of the software are reliable,and the results are in good agreement with the actual situation,and satisfied with the requirements of engineering accuracy.Through the comparison of experimental research and calculation with software guidelines we found that : in the case of the natural oil flow guiding transformer in thecondition of air cooling or self cooling,the winding response is relatively rapid,and the oil flow response is relatively lagging in the process of non steady flow.The temperature of winding at the beginning rises fast,quickly reached a balance,later the temperature rise of the is very small,and the oil flow in the lagging winding for a period of time after the beginning of the rapid rise,and ultimately to achieve balance.