同步调相机极限工况下典型磁场不对称故障安全风险

同步调相机典型磁场不对称故障下，由强励所形成的不平衡力和跳机风险升高。首先，分析转子动偏心和转子绕组匝间短路等典型故障对调相机磁场的影响机理；然后，借助气隙磁导法推导得到转子承受的不平衡磁拉力表达式，分析强励对不平衡电磁力的影响规律；最后，在一台大型同步电机上进行有限元电磁暂态仿真，模拟动偏心和转子绕组匝间短路故障，分别在调相正常励磁和强励工况下提取了转子所受不平衡电磁力，评估机组在强励状态下发生跳机的可能性。结果表明，强励状态下，调相机组由动偏心故障产生的不平衡磁拉力不会引起机组的剧烈振动，而转子匝间短路故障产生了较大的不平衡磁拉力，可能导致机组跳机。

Safety Risk of Synchronous Condenser with Typical Asymmetric Magnetic Field Faults Under Extreme Operating Conditions

Under typical magnetic field asymmetry faults, the synchronous condenser has an increase in unbalance force formed by forced excitation and tripping risk. Firstly, an analysis is made of the influence mechanism of typical faults such as rotor dynamic eccentricity and rotor winding inter-turn short circuit on the magnetic field of the synchronous condenser. Then, the expression of unbalanced magnetic pull on the rotor is derived using air-gap permeance method, and the influence of forced excitation on the unbalanced electromagnetic force is further analyzed. Finally, the finite element electromagnetic transient simulation is carried out on a large synchronous machine to simulate the dynamic eccentricity and the rotor winding inter-turn short circuit fault. The unbalanced electromagnetic force on the rotor is extracted respectively under the conditions of normal excitation and forced excitation, and the possibility of tripping under forced excitation is evaluated. The results show that under the forced excitation, the unbalanced magnetic pull produced by the dynamic eccentricity fault of synchronous condensers will not cause severe vibration of the unit, while the rotor inter-turn short circuit fault produces a big unbalanced magnetic pull, which may result in the unit tripping.