均匀高温绝缘系统油浸式配电变压器结构优化设计

摘要

With the rise of safety,economic and environmental protection requirements of power systems,replacingthe insulation materials to enhance the performance of oil-immersed distribution transformer is high needed.Based on the classical theory of heat transfer," Loading guide for oil-immersed power transformers" and "Design and application of liquid-immersed transformers using high-temperature insulation material",the well-distributed high temperature insulation system of oil-immersed distribution transformer using new insulation materials was studied.According to the performance differences between new insulation materials and conventional insulation materials,the heat dissipating capacity of the well-distributed high temperature transformer and the conventional transformer was compared using the theory of heat convection.According to the guidelines,the overload temperature limit of oil-immersed transformers in different insulation systems were determined and the hot spot temperature calculation model suitable for the well-distributed high temperature transformer wasobtained.In order to obtain the differences of heat resistance,the permissible overload times of different transformers under long term emergency load was compared.On the basis of performance comparison,a structure optimization method for the well-distributed high temperature transformer was proposed and the manufacturing cost changes were calculated.It was found thatwhile the heat dissipation capability of the well-distributed high temperature transformer is 80.2％ of that of the conventional transformer,the heat resistance of the former is up to 119％ of the latter.The conclusion showed that a well-distributed high temperature transformer could be obtained by reducing the winding radius,the iron core volume,the tank volume,the amount of the insulating material,simultaneously widening the oil path,the oil inlet and outlet diametersand increasing the number of the radiators.The hot spot temperature limit can be raiscdfrom 140 ℃ to 170 ℃ with the total costincreaseof 34％ by replacing the conventional insulation materials with new insulation materials and optimizing the structure.%随着电力系统安全可靠性和经济环保性要求的不断提高,亟需更换绝缘材料以提升油浸式配电变压器性能.基于传热学经典理论、油浸式电力变压器负载导则和采用高温绝缘材料的液浸式变压器设计和应用导则,针对采用新型绝缘材料的均匀高温绝缘系统油浸式配电变压器进行研究.根据新型绝缘材料与常规绝缘材料的性能差异,利用热对流经典理论对比均匀高温绝缘系统配变和常规绝缘系统配变的散热能力;依据导则确定不同绝缘系统油浸式配变的过载温度限值,改进得到适用于均匀高温绝缘系统配变的热点温度计算模型,对比均匀高温绝缘系统配变和常规绝缘系统配变在长期急救负载下的允许过载倍数,以获得二者的耐热能力差异;基于性能对比,提出均匀高温绝缘系统配变的结构优化设计方案,并计算由此带来的制造成本改变.结果显示均匀高温绝缘系统配变的散热能力约为常规绝缘系统配变的80.2％,但耐热能力可达到常规绝缘系统配变的119％.结论表明:可缩小均匀高温绝缘系统配变的绕组导线线径、铁心体积、箱体体积、减少绝缘材料用量,同时加宽其绕组油道和进、出口油径、增加散热器数量,即在更换常规绝缘系统油浸式配变绝缘材料的同时对其结构进行优化调整,可在总成本提高约34％的情况下将油浸式配变的耐温限值由140℃提升至170℃.