To research the variation characteristics and influence factors of air gap magnetic field and electromagnetic torque of nuclear power half-speed turbine generator with stator winding inter-turn short circuit, the two-dimensional transient electromagnetic field of generator-external circuit-grid coupling mathematical model is established by field-circuit-network coupling method. Taking the national laboratory’s generator as an example, and comparing the simulation results of the inter-turn short circuit of the armature winding with experimental data, the correctness of the model is validated. On this basis, the simulation model of a 1407MVA nuclear power half-speed turbine generator is built. Then the stator winding inter-turn short circuit fault is simulated when the generator is connected to the grid with rated load. The characteristics of air gap flux density and electromagnetic torque are obtained before and after fault, as well as, the relationship between their each component and the fault degree is obtained. At the same time, the variation law of air gap flux density and electromagnetic torque is obtained when the relative position between fault winding and magnetic pole changes. The theoretical reference for fault diagnosis and localization using harmonic electromagnetic torque after fault is provided.

研究定子绕组匝间短路的核电半速涡轮发电机气隙磁场和电磁转矩的变化特征及影响因素，发电机的二维瞬变电磁场-外部电路-电网耦合数学模型通过现场-电路-网络耦合方法建立。以国家实验室的发电机为例，将电枢绕组匝间短路的仿真结果与实验数据进行比较，验证了模型的正确性。在此基础上，建立了1407MVA核电半速涡轮发电机的仿真模型。然后，当发电机以额定负载连接到电网时，将模拟定子绕组匝间短路故障。求出了故障前后的气隙磁通密度和电磁转矩的特性，并确定了各分量与故障程度之间的关系。同时，当故障绕组与磁极之间的相对位置发生变化时，可获得气隙磁通密度和电磁转矩的变化规律。为故障后谐波电磁转矩的故障诊断和定位提供了理论依据。