负序零序电流对抽水蓄能电动机电磁转矩的影响

Influence of negative sequence and zero sequence current on electromagnetic torque of pumped storage motor

针对抽水蓄能电动机数值分析和计算过程较为困难的问题,提出一种新型改进网络参数法。通过分析正序、负序和零序网络系统电磁转矩与电磁功率的关系,推导出电动机在稳定运行状态下基波电磁转矩和二次谐波电磁转矩的表达式,利用有限元法获取抽水蓄能电动机的电磁转矩,验证改进网络参数法的有效性。结果表明,同时改变负序电流和零序电流不对称度大小,得到相应电动机在额定、3/4额定和1/2额定电流稳定运行状态下电磁转矩随电流不对称度大小改变的变化趋势。

This paper proposes a new improved network parameter method to address the difficulty of numerical analysis and calculation of pumped storage motor.The study is accomplished by analyzing positive sequence network system,negative sequence network system and zero sequence network system;deriving the expressions of fundamental electromagnetic torque and second harmonic electromagnetic torque in the stable state based on the relationship between electromagnetic torque and electromagnetic power;obtaining electromagnetic torque of the pumped storage motor by using finite element method to verify the effectiveness of the improved network parameter method.The results show that the variation trend of electromagnetic torque can be obtained along with the simultaneous change of asymmetry of negative sequence current and zero sequence currentt,under the three steady operating states of the rated current,3/4 rated current and 1/2 rated current.