中文摘要：

建立了高压发电机（Powerformer）的定子绕组内部相问故障和接地故障分析的数学模型。该模型以直接相量法为依据，并且考虑了定子绕组对地电容的影响。为准确地仿真内部故障时地情形，计算了各个故障分支磁轴的正方向。模型建立了转子和定子的电流方程、电压方程和磁链方程，并且以一个75MVA/150kV的高压发电机为模型，详细仿真了单相接地故障、两相接地故障和相间短路故障的情况并且给出了故障波形。利用该模型可以对高压发电机的保护方案进行有效的验证或者作相应的改进。

英文摘要：

A mathematical model of a synchronous machine （powerformer）, which can analyze internal phase to phase and phase（s） to ground faults in stator windings, is proposed in this paper. The method takes the cable capacitance into account and employs a direct phase representation. To effectively implement the internal fault simulation, the magnetic axis locations of fault parts are arranged appropriately The current equivalent equations, voltage equivalent equations and the rotor motion equations are formed and combined to implement the fault simulations. Simulation results of a 75MVA and 150kV powerformer during a single phase to ground fault, a two phase to ground fault and a phase to phase fault, are presented. With the data generated by this internal fault simulation model, the protection scheme used for powerformer can be validated and improved accordingly.