Continuous periodic disturbance may cause the forced power oscillation in power system,which is greatly different from that of classic under-damping free-oscillation in both generation mechanism and oscillation characteristics.The energy characteristics during forced power oscillation are analyzed from the point of work-energy transformation.The function of work-energy relation during forced oscillation is established according to the steady-state response and the cause of equal-amplitude forced oscillation is explained by the change of system energy.With a real power system as an example,the work-energy transformation during oscillation is analyzed and the system energy variation is compared between different oscillating-source frequencies,based on which,the operational features are analyzed for three kinds of energy resonance.%持续的周期性扰动会引发电力系统强迫功率振荡,从产生机理到振荡特征强迫功率振荡均与经典弱阻尼自由振荡有较大的区别.从功-能转换的角度分析了强迫功率振荡过程中的能量特性.首先根据系统发生强迫功率振荡时的稳态响应建立强迫振荡过程中的功-能关系函数,然后利用系统的能量变化关系分析系统发生等幅受迫振荡的原因并以实际系统为例分析振荡过程中的功-能变化过程,比较了不同强迫振荡源频率时对应系统的能量变化情况,最后在上述分析的基础上研究了系统在3种能量共振状态时的运行特性.
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