定子回路电阻对次同步谐振的影响

摘要

In order to give a further discussion on the influence of the stator circuit resistance on the electrical damping, analysis method and simulation are both employed in this paper. The electromagnetic torque increment under the system subjecting to a small perturbation was derived, and the relevant part of stator circuit resistance was disassembled to synchronous torque and damping torque. According to the parameters provided by IEEE first benchmark model (FBM) , the damping torque coefficient of generator and that related to the stator circuit resistance were discussed. Finally, the relationships between the e-lectrical damping and the stator circuit resistance were obtained, The results show that due to the decrease of the stator circuit resistance, the electrical damping declines, and the torsional oscillation between different cylinders in the turbine generator intensifies, some even diverges in spite of convergence at first. Therefore, the resistance of each component in the generator stator circuit needs to be handled carefully in the research of subsynchronous resonance (SSR) of power system; otherwise it would make the accuracy of analysis results decline, or even get the wrong conclusion. The simulation results are in line with the conclusions achieved by the analysis method.%为了深入讨论定子回路电阻对电气阻尼的影响,采用解析与仿真相结合对其进行研究.推导了系统在受到小扰动时发电机电磁转矩的增量,并将其中与定子回路电阻相关的部分分解成同步转矩分量与阻尼转矩分量之和,然后结合IEEE次同步谐振第一标准模型参数,对同步电机及与定子回路电阻相关的阻尼转矩系数进行讨论,得出定子回路电阻与阻尼转矩系数之间的关系.结果表明:当定子回路电阻减小时,系统电气阻尼将减小,机组各轴段间的扭振加剧,有些轴段间的振荡甚至由收敛变为发散.因此,在次同步谐振研究过程中,需谨慎处理发电机定子回路中各元件的电阻,否则会使得分析结果与实际偏差较大,甚至得到错误的结论.仿真结果与解析法所得结论一致.