电力系统强迫功率振荡的基础理论

以单机无穷大系统模型为基础,阐述了电力系统强迫功率振荡的基础理论,分析了影响电力系统强迫功率振荡的主要因素,并对单机无穷大系统的强迫功率振荡进行了仿真验证。电力系统强迫功率振荡理论指出,持续的周期性小扰动会引起电力系统强迫振荡,当扰动频率接近系统固有振荡频率时,会引起系统谐振,导致大幅度的功率振荡。谐振引起的强迫振荡的幅值与扰动的幅值、系统固有的振荡阻尼大小有关:扰动的幅值越大,谐振幅值越大;系统固有的振荡阻尼越强,谐振幅值越小。谐振引起的强迫振荡的表现形式类似于属于自由振荡的电力系统负阻尼低频振荡,但两种振荡的起因不同。

Fundamental Theory of Forced Power Oscillation in Power System

The fundamental theory of forced power oscillation in power system is explained by a single-machine infinite-bus power system model. The main factors related to the forced power oscillation are analyzed, and the forced power oscillation in the single-machine infinite-bus power system is verified by digital simulation. The theory of forced power oscillation in power system proves that the forced power oscillation may be caused by a sustained cyclic small disturbance in power system, and the resonance could be induced if the frequency of the sustained cyclic small disturbance is close to an inherent oscillation frequency, so that it leads to forced power oscillation with high amplitude. The amplitude of forced power oscillation induced by resonance is related with the amplitude of disturbance and the damping of the inherent oscillation mode. The higher the amplitude of disturbance is, the larger the amplitude of resonance is; the stronger the damping of the inherent oscillation mode is, the smaller the amplitude of resonance is. The behavior of forced power oscillation induced by resonance is similar to that of low frequency power oscillation induced by negative damping which is one of free oscillations, but the causes of these two types of power oscillations are different.