为了准确模拟水轮发电机定子故障下的阻尼条损耗,建立场、路、运动直接耦合的时步有限元分析模型,对电机的电磁场方程和定子绕组、阻尼绕组的等效电路方程实现联立求解.通过改变定子外电路方程模拟不同定子端部短路故障类型,求解水轮发电机定子端部各类短路故障下阻尼条中的电流波形以及电流密度和损耗分布情况.根据对225MW水轮发电机所作的时步有限元分析,得到定子单相接地短路、两相短路和三相短路故障下的阻尼条损耗分布与相关结论,定子不对称故障下阻尼绕组中的损耗较大,且损耗最大的阻尼条均为背风面的那一根.
A field-circuit-motion directly coupled time-stepping finite-element analysis model was established to accurately simulate the losses of damper bars on different conditions of stator faults.Then the electromagnetic field equations,stator windings and damper windings equivalent circuit equations were simultaneously solved.All the short circuit calculations of hydro-generator stator can be implemented by changing external stator circuits,which results in damper bar current waveform,the distribution of damper bar current density and its corresponding losses as well.A 225 MW hydro-generator running under single-phase to ground fault,two-phase short circuit fault and three-phase short circuit fault operations were respectively calculated.The distributions of damper bars losses and relevant conclusions were got.The losses of damper bars are larger under asymmetric stator faults,and the damper bar with the largest losses is close to the leeward side.