One of the key aspects of the teaching reform of the higher vocational colleges is to give prominence to the ability training of the students. In this paper, from the teaching practice of the network marketing course,...One of the key aspects of the teaching reform of the higher vocational colleges is to give prominence to the ability training of the students. In this paper, from the teaching practice of the network marketing course, with the applicative competition platform as the breakthrough point, the author carries through a series of teaching reforms, to realize the goal of training, and especially to give prominence to the ability training of the students.展开更多
Currently,the design of transformers insulation predominantly depends on the allowable alternating current(AC)field values for insulating oil established by Weidmann in the 1980s,lacking the research under direct curr...Currently,the design of transformers insulation predominantly depends on the allowable alternating current(AC)field values for insulating oil established by Weidmann in the 1980s,lacking the research under direct current(DC)voltage for converter transformers.This study selects naphthenic oils and paraffin-based oil transformer oil as research subjects,establishing a practical measurement platform to ascertain the oil breakdown characteristics under DC voltage.Furthermore,it statistically analyses the allowable DC field values of the oil.The findings elucidate that(1)the three-parameter Weibull dis-tribution is more suitable to conduct a statistical analysis for oil breakdown probability,yielding a fitting degree up to 99.95%.(2)For a constant electrode spacing,a 14.81%voltage increment escalates the breakdown probability of the oil gap from 3.33%to 73.33%.Concurrently,an increase in electrode spacing leads to a substantial decrement in the breakdown field strength of transformer oil,with KI25X experiencing a 54.51%reduction as electrode spacing extends from 5 to 25 mm.(3)The constant terms of the allowable DC field strength for S4,KI50X,and KI25X are found to be 19.728,17.221,and 19.281,respectively.(4)A thorough analysis for differences in physicochemical properties and electrical parameters elucidates the variations in insulation properties across different transformer oils.The findings presented in this study offer essential theoretical and technical foundations for the design,evaluation,and enhancement of insulation structures in converter transformers.展开更多
文摘One of the key aspects of the teaching reform of the higher vocational colleges is to give prominence to the ability training of the students. In this paper, from the teaching practice of the network marketing course, with the applicative competition platform as the breakthrough point, the author carries through a series of teaching reforms, to realize the goal of training, and especially to give prominence to the ability training of the students.
基金National Natural Science Foundation of China,Grant/Award Number:52107148China Postdoctoral Science Foundation,Grant/Award Number:2020M680485Fundamental Research Funds for the Central-Universities,Grant/Award Number:2021MS004。
文摘Currently,the design of transformers insulation predominantly depends on the allowable alternating current(AC)field values for insulating oil established by Weidmann in the 1980s,lacking the research under direct current(DC)voltage for converter transformers.This study selects naphthenic oils and paraffin-based oil transformer oil as research subjects,establishing a practical measurement platform to ascertain the oil breakdown characteristics under DC voltage.Furthermore,it statistically analyses the allowable DC field values of the oil.The findings elucidate that(1)the three-parameter Weibull dis-tribution is more suitable to conduct a statistical analysis for oil breakdown probability,yielding a fitting degree up to 99.95%.(2)For a constant electrode spacing,a 14.81%voltage increment escalates the breakdown probability of the oil gap from 3.33%to 73.33%.Concurrently,an increase in electrode spacing leads to a substantial decrement in the breakdown field strength of transformer oil,with KI25X experiencing a 54.51%reduction as electrode spacing extends from 5 to 25 mm.(3)The constant terms of the allowable DC field strength for S4,KI50X,and KI25X are found to be 19.728,17.221,and 19.281,respectively.(4)A thorough analysis for differences in physicochemical properties and electrical parameters elucidates the variations in insulation properties across different transformer oils.The findings presented in this study offer essential theoretical and technical foundations for the design,evaluation,and enhancement of insulation structures in converter transformers.
