考虑气隙偏心时发电机定子匝间短路位置对电磁转矩波动特性的影响

针对同步发电机定子匝间短路位置对电磁转矩波动特性的影响进行理论推导分析、计算机数值仿真和动模实验验证。首先,对发电机气隙偏心单故障和气隙偏心与定子匝间短路复合故障下的电磁转矩表达式进行推导,分析得到了短路位置与电磁转矩特征频率幅值的映射关系。然后,以实验室MJF-30-6型动模发电机组为验证平台和建模对象,应用有限元软件Ansoft建立求解模型,对不同短路位置下的电磁转矩进行了仿真计算,并在实际机组上进行了实验测试。实验结果与理论分析、计算机数值仿真数据相吻合。分析表明,电磁转矩与短路位置和最小气隙位置的夹角近似呈余弦变化的映射关系,短路匝中心位置与最小气隙位置越接近,则电磁转矩平均值下降越多、二倍频和四倍频转矩分量幅值增大越多。该文是对定子匝间短路故障分析的一个重要补充,对此类故障的实际监测与识别具有参考价值。

Effect of Stator Inter-Turn Short Circuit Position on Electromagnetic Torque of Generator with Consideration of Air-Gap Eccentricity

This paper investigated the effect of the stator inter-turn short circuit position on the electromagnetic torque of generator by theoretical analysis,numerical simulation,and experiment verification.Firstly,the detailed expressions of the electromagnetic torque respectively under static air-gap eccentricity fault and static air-gap eccentricity & stator inter-turn short circuit composite faults are deduced to obtain the mapping relationship between the shorted position and the electromagnetic torque.Then,the experiment study and the simulation work are taken based on the MJF-30-6 type fault simulating generator.The finite element method(FEM) model of this generator was set up in Ansoft to calculate the electromagnetic torque under the composite faults with different shorted positions.The experimental tested data had the consistent result with the theoretical analysis and simulation data.It is shown that,the mapping relation of the electromagnetic torque and the angle between the shorted position and the min air-gap position is generally in cosine pattern.The closer the shorted position is near the min air-gap position,the more mean electromagnetic torque would be decreased,while the 2nd and 4th components would be increased more.The achievement obtained in this paper is a significant supplement to the stator inter-turn short circuit analysis and would be beneficial to the practical monitoring and diagnosis on this fault.