Research On The Calculation Of Temperature Field And It’s Proportional Hazards Model Of Large Oil-immersed Transformer

Power transformer is the core equipment of the power system, its operation relateto the security and reliability of electricity supplying to millions of households.Transformer temperature rise is directly related to the transformer insulation life andsafety of operation, so the transformer winding hot spot temperature is an importantindicator to the measure of the merits of the transformer design. Compared to thetransformer with forced oil circulation, the natural circulation in the transformer oiland the oil flow of heat transfer situation is more complex, and although with theradiator and fans, but the flow rate of oil is still high, so the cooling effect is poor. Tofurther explore the temperature distribution of natural oil circulation transformer, theresearch of factors affect transformer’s hot spot temperature is needed, including theload, ambient temperature, fan controlling and so on.In this paper, we use finite volume method to Simulate and Analyse thethree-dimensional temperature field and temperature distribution of hot spots ofSFSZ10-M-31500/110large naturally oil circulation transformer (cooling method:ONAF). Simulation calculations fully account of the heat sink and fan controlling’saffect to the distribution of the temperature field and hot spot. Establish transformersmodel(including heat sink) according to its true proportion. By simulating itsthree-dimensional temperature field, we have analysed its temperature distributionand the hottest temperature position under different load, and the simulation resultswere compared with the calculation result. These studies has some significance to thestructural optimization of the transformer, and it also provides a basis for positioningwinding hot spot temperature of the natural oil-cooled transformer measured byfiber-optic..Large oil-immersed transformers’ traditional repair methods is regular maintenance,it exists insufficient maintenance and repairs over deficiencies.In this paper,we use themonitored top oil temperature and winding hot spot temperature as the basiccharacteristic quantity of the SFSZ10-M-31500/110large oil-immersed transformer,using Weibull failure model to establish a relationship between running state and thethe failure rate of large oil-immersed transformer,aiming at minimize maintenancecosts, identificate maintenance strategy based on PHM, programming in VC++toachieve PHM maintenance strategy.Develop a PHM-based diagnostic software forSFSZ10-M-31500/110large oil-immersed transformer based on its top oiltemperature and winding hot spot temperature, this software isused for diagnosis method can effectively solve the problems of traditional repair methods, namelymaintenance of excessive or insufficient maintenance, to achieve large-scaleoil-immersed transformers’ purpose of " demanding maintenance".