励磁系统及电力系统稳定器对发电机组次同步谐振阻尼特性的影响

Effect of Exciter and Power System Stabilizer on Subsynchronous Resonance Damping

采用时域仿真实现的复转矩系数法,测试信号法,以IEEEAC1A型、AC2A型以及ST1A型3种标准的励磁系统和IEEE单通道的电力系统稳定器(powersystemstabilizer,PSS)为研究对象,分析了它们对发电机组次同步谐振阻尼特性的影响。通过频率扫描计算发电机组在次同步频率下的电气阻尼特性曲线,从而对各种励磁系统在无PSS以及装设不同输入信号的PSS情况下对电气阻尼特性的影响进行了分析;并分析了PSS参数对电气阻尼特性的影响。分析结果表明,高起始响应励磁系统在与以发电机输出电磁功率作为输入信号的PSS配合使用时,能够减小谐振点附近的电气负阻尼,使得其在抑制低频振荡的同时,还有利于缓解次同步谐振。

Taking three types of standard IEEE excitation systems, i.e., IEEE AC1A, IEEE AC2A and IEEE ST1A, and the IEEE single channel power system stabilizer （PSS） as objects to be investigated, by means of complex torque coefficient approach, namely the test signal method, realized by time domain simulation, the influences of these research objects on damping characteristics of unit＇s subsynchronous resonance （SSR） are studied. Frequency scanning in the subsynchronous frequency range is performed to calculate the subsynchronous electrical damping characteristics of the unit under subsynchronous frequency, thus the influences of various excitation systems, in which PSS is not equipped or PSSs with different input signals are equipped, on electrical damping characteristics of unit are analyzed, and the effects of parameters of PSS on electrical damping are also researched. Research results show that the electrical negative damping around the resonance point can be reduced while the excitation systems with high initial response, such as IEEE AC2A and IEEE ST1A, are co-operated with the PSS which takes the output electromagnetic power of generator as its input signal, so not only power swing oscillations can be eliminated, but also the SSR can be mitigated.