具有磁性和非磁性槽楔的汽轮发电机转子槽分度的计算与分析

Calculation and analysis of slot pitch coefficient of turbo-generator rotor with magnetic and non-magnetic slot wedges

为了研究汽轮发电机转子不同槽分度对电机电磁场的影响,以150 WM空冷汽轮发电机为例,建立了汽轮发电机的二维数学模型和物理模型。采用二维有限元方法,计算了转子带有非磁性槽楔和磁性槽楔时不同槽分度下的电磁场及发电机的饱和电抗值,并在此基础上研究了不同槽分度情况下非磁性和磁性材料的3种转子槽楔对发电机定、转子损耗的影响。计算结果表明,转子采用弱磁性槽楔和导磁导电的Fe-Cu合金槽楔后,发电机的饱和同步电抗相对于铝合金槽楔对应的饱和同步电抗减小,同时可以有效减小气隙磁密中的谐波含量,降低表面损耗。计算结果为发电机转子磁性槽楔和槽分度的选择设计提供了理论依据。

A 150WM air-cooled turbo-generator was taken as an example to investigate the effects of different slot pitch coefficients of the turbo-generator rotor on electromagnetic field. First, the 2D mathematical model and physical model of the turbo-generator was established. Adopting 2D finite-element method, the saturation reactance value and electromagnetic field of different slot pitch coefficients were calculated when magnetic and non-magnetic slot wedges were used on the generator rotor, respectively. Mean- while, under the condition of applying different slot pitch coefficients, the magnetic and non-magnetic material of three kinds of rotor slot wedge were studied on the influence of the generator stator losses and rotor losses. The results show that the rotor with weak magnetic slot wedge and magnetic conductive Fe- Cu alloy slot wedge reduces the harmonic of air-gap flux density effectively and the surface losses. At the same time, the generator of saturation synchronous reactance relative to the aluminum slot wedge corre- sponding saturation synchronous reactance is reduced. The results present theoretical basis for selection and design of magnetic slot wedge and slot pitch coefficient of the generator rotor.