The accurate calculation of electromagnetic torque is very important for stability analysis of generator and power system. In order to compare the calculation precision and applicability of different methods, the calculation formulas based on the Maxwell stress method are deduced on three kinds of traditional integral paths. Then, taking 300MW turbo-generator as example , the relative errors by means of seven electromagnetic torque calculation methods including the traditional Maxwell stress method, the improved Maxwell stress method, the local Jacobin derivative method and so on are studied and compared under different air gap mesh strategies and load conditions. The study shows that the shape of integration path have little effect on the calculation results of the traditional Maxwell stress method while the integration path is located on the same air gap layer. The methods based on virtual work principle are more easily affected by the gap mesh strategy under light loads. Accordingly, the Maxwell stress method should be taken under light load conditions.%电磁转矩的准确计算对发电机和电力系统稳定分析具有重要意义.为比较不同算法的计算精度和适用范围,本文推导了传统麦克斯韦应力法在三种常用积分路径下的计算公式,并以300MW汽轮发电机为例,在不同负荷和气隙剖分策略下对比研究了传统麦克斯韦应力法、改进麦克斯韦应力法和局部雅克比导数法等七种方法的计算误差.研究表明当积分路径位于相同气隙层时,积分路径的形状对传统麦克斯韦应力法计算结果的影响不大;低负荷时基于虚位移原理的计算方法容易受到气隙剖分策略的影响,因此在低负荷状态下,应尽量采用麦克斯韦应力法.
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