In order to further improve the air drying quality of the rotor winding of oil immersed transformers, there are two factors that should be carefully and comprehensively considered: first, controlling the drying working temperature; The second is to improve the vacuum value of facilities and equipment. General drying machinery can ensure the production process requirements, but for the second point, it is affected by many negative factors and should be considered comprehensively and scientifically to obtain a better drying prediction.
During the process of vacuum preservation during drying, it is not suitable for vacuum preservation or drying under low mechanical pump conditions during the relatively low temperature stage of slow drying. Otherwise, it is not good to increase the working temperature of the coil of the oil-immersed transformer and eliminate cold and humidity. When the working temperature rises to 70-80 ℃, slowly increase the vacuum pump value.
When drying for 1-2 hours, there is more water vapor in the oil tank, which improves the ability to work with radiant heat. The working temperature of the internal structure tends to be uniform, and the moisture gradually decreases. The professional ability to work with radiant heat also decreases. The method for identifying insulation pipes after drying and the performance parameters of the oil transformer to be tested. Hengfengyou Electric can conduct a multi-dimensional evaluation of its surface resistivity as much as possible to check its dryness prediction. Evaluate the new project, except for the rigid waterproof casing, everything else is the same as testing the new project during suspension maintenance.
Working temperature is an externally standardized definition, and the ecological environment protection of oil-immersed transformers is affected and constrained by working temperature. Without high-quality working temperature, oil-immersed transformers cannot operate with high quality. In terms of the working temperature of oil-immersed transformers, it not only determines the operation of the transformer, but also endangers the selected service life of the transformer. Therefore, it is important to grasp the working temperature of the transformer. Operating an oil immersed transformer at a suitable operating temperature is beneficial for improving the service life of the oil immersed transformer. What is the relationship between the two?
For the installation of oil immersed transformers in power equipment, the vast majority choose tinfoil insulation sleeves or A-grade cable sheaths. For oil immersed transformers with Class A grounding wire resistance, under normal operation, when the working temperature of the surrounding gas is 40 ℃, the standard operating temperature for the winding resistance of the oil immersed transformer is 105 ℃.
Social practice and research have found that if the winding resistance can continuously maintain a working temperature of 95 ℃, it can ensure that the oil immersed transformer has a 20 year application deadline. Based on the relationship between working temperature and time, a commonly used 8 ℃ law can also be derived: with the service life above the working temperature as the majority, for every 8 ℃ increase in winding resistance working temperature, the use of oil-immersed transformers decreases by half.
