不对称转子结构双轴励磁电机同步电抗计算

Synchronous Reactance of Dual-Excited Synchronous Generator with Asymmetric Rotor Structure

双轴励磁同步电机(双励机)具有高稳定性和深度进相运行能力,对于提升电力系统稳定性、抑制系统过电压具有重要意义。具有两相不对称正交转子绕组结构的双励机转子热负荷低、结构简单,但也导致其磁路结构与传统同步电机有很大不同,进而影响同步电抗的大小。本文建立了双励机的时步有限元模型,分析了励磁方式对励磁磁动势与运行工况对气隙合成磁动势,即对同步电抗的影响。采用两种方法计算了不对称转子结构双励机的同步电抗,对比研究了双励机与传统同步电机同步电抗的差异,揭示了不同励磁方式下双励机同步电抗随功角的变化规律。研究结果可为双励机的精确仿真计算提供理论依据。

The high stability and deep under-excitation operation capability of the dual excited synchronous generator(DESG)is of great importance for improving the stability and suppressing the overvoltage of the power system.The DESG with two-phase asymmetrical orthometric field winding structures has the characteristics of the low rotor thermal load and simple structure,but it also causes the rotor magnetic circuit structure to be very different from that of traditional synchronous generator(TSG),which in turn affects the value of synchronous reactance.In this paper,the time-stepping finite element model of DESG is established.The influence of excitation modes on excitation magnetomotive force and operating conditions on air gap synthetic magnetomotive force,that is,on synchronous reactance,are analysed.The d-axis and q-axis synchronous reactance of the DESG are calculated by two methods and compared with the TSG.Further,the variation of the synchronous reactance of the DESG along the power angle is revealed.The results can provide the theoretic basis for the accurate simulation calculation of the DESG.