汽轮机调速系统对电网低频振荡的影响

近年来电力系统中频繁出现汽轮机调速系统引发的低频振荡,为了探明该类低频振荡的原因,分析了调速系统对电力系统动态稳定的影响。建立了包含汽轮机调速系统的单机无限大系统模型,研究了调速系统增益对系统低频振荡模态的影响。研究结果表明,汽轮机调速系统增益虽然不改变调速系统阻尼特性分界频率,但是却对系统低频振荡模态频率产生影响,从而改变调速系统对低频振荡的阻尼性质。当调速系统增益超过临界增益时会诱发低频振荡现象,时域仿真和频域分析结果验证了上述结论的正确性。

The Impact of Steam Turbine Governor System on the Low Frequency Oscillation of Power Grids

In recent years low frequency oscillations induced by steam turbine governor system often occur in power system. For finding out the cause of this kind of low frequency oscillation, the effect of governor system on power system dynamic stability was thoroughly analyzed. One machine infinite bus model including steam turbine governor system was put up and the effect of governor sys- tem gain on low frequency oscillation mode was researched. The study result indicate that although the dividing line frequency of damping characteristic cannot be changed by governor system gain, the mode frequency of power system low frequency oscillation will be influenced. Consequently, the damping character of governor system on low frequency was changed. If the gain of governor system exceeds the critical gain, low frequency oscillation will be aroused. Time domain simulation and frequency domain analysis proved the correctness of the above conclusion.