为研究水轮发电机的稳态负序运行能力,根据电磁场和传热学的相关理论,在考虑阻尼绕组气隙的基础上建立水轮发电机电磁场和温度场相耦合的二维有限元模型;用相对运动等效的方法处理转子的旋转问题,建立等效时谐场分析负序电流在转子中产生的涡流,得到发电机在负序稳态运行时阻尼绕组的涡流损耗分布;并将损耗结果耦合到温度场中最终得到精确的阻尼绕组温度分布。以一台容量为250 MW的水轮发电机为例,验证所提方法的正确性,经计算表明该电机具有9%稳态负序运行能力。
To study the negative sequence capacity of hydro-generator,the 2-D electromagnetic and thermal finite-element models which have considered the damper air-gap between the damper windings and the pole shoe were established based on the theories of electromagnetic and heat transfer.For the rotation of the rotor,an equivalent method was adopted.After the eddy current loss distribution of the damper windings was got,a coupling method was taken to apply the eddy current loss to the thermal field in order to acquire more accurate temperature distribution of the damper winding.A 250 MW hydro-generator was taken as an example to verify the feasibility of the equivalent method and study the impact of the damper air-gap modeling and the coupling method on the temperature distribution of the damper winding.At last,the hydro-generator was tested that it had 9% negative sequence capacity.