中文摘要：

把变压器看作含互感支路的电网络。作出了新型换流变压器耦合电路的有向图，基于此有向图，首次将添加法应用于建立含互感支路的电网络的网络方程，从而得到了新型换流变压器正常状态的数学模型．并根据有向图节点或支路的变化．通过修改相关的支路对网络方程的贡献来建立新型换流变压器的内部故障数学模型和计算其典型的内外部短路故障。实际算例验证了所建数学模型和短路故障计算方法的正确性。该算法具有占用计算机内存小、计算效率及精度高、通用性强等特点．它不仅可以十分便捷地直接形成新型换流变压器的正常状态和内部故障数学模型．而且可以计算其任意的内外部短路故障．能用于解决各种复杂多绕组变压器正常状态、内部故障的数学建模及任意的内外部短路故障计算等问题。

英文摘要：

A digraph of coupled circuit is made for converter transformer,where the transformer is regarded as an electric network containing coupled branches,and based on which,the additive process is applied to directly build the equations of electric network containing coupled branches and the mathematical models of converter transformer in normal condition are thus obtained. For calculating its typical internal and external faults,the mathematical models of converter transformer in the condition of interior fault are obtained by amending the correlative contribution of branches according to the change of nodes and branches. Actual examples validate the correctness of the method of mathematical modeling and fault calculation,which needs less computer memory and has higher computational efficiency,accuracy and versatility. It is suitable for the mathematical modeling of complex multi-winding transformer in normal and interior fault conditions and the calculation of arbitrary internal and external faults.