计算Scott牵引变压器内部温升的热路模型法

牵引变压器的绝缘寿命很大程度上取决于绕组热点温度,研究其内部温升具有重要意义。为此,针对Scott牵引变压器特殊的绕组连接、铁心结构和电气特性,利用热传输原理分析了其内部热量的产生和传输过程;参考电路原理建立了Scott牵引变压器内部热路模型;参照基尔霍夫定理推导了温升的计算式,从而建立了Scott牵引变压器的热路温升计算模型和简化的热路温升计算模型;采用两种热路温升计算模型和IEC温升计算法仿真了同一负荷下的Scott牵引变压器,仿真结果说明了模型的有效性。

Heat Circuit Method for Calculating Temperature Rise of Scott Traction Transformer

The insulation life of a traction transformer is determined partially by hot-spot temperature and depends on the ability of the transformer to dissipate the internally generated heat to its surroundings.Scott connected traction transformers are three-phase to two-phase balancing transformers,and it is of significance to study on the inner temperature rise in this kind of traction transformer,especially the hot-spot temperature rise and the corresponding calculation method,which is quite different from power transformers due to the different winding connection and the different loads,the traction loads are impacted loadings.According to the especial winding connection,the core structure and the electric characteristic,producing and transfer of the heat in Scott connected traction transformer are analyzed by simply using momentum,heat,and mass transfer principle.And referring to electric circuit principle,the heat circuit of Scott connected traction transformer is then proposed.On the basis of analyzing the current and resistance of the windings,the relations of the load losses of the windings and the load losses of the Scott connected traction transformer under rated loads are obtained.According to the basic role of heat circuit,the calculating model based on heat circuit for calculating inner temperature rise of Scott connected traction transformer is deduced,which is simplified to obtain the simplified heat circuit.Heat circle method is validated by comparing the simulating results under the impacted loads using the heat circle method and IEC method.