基于电气量频率差异的电力系统振荡识别

摘要

Characteristics of the voltage frequency and current frequency of oscillation center and non-oscillation-center are analyzed.Studies show that during power system oscillations,the voltage frequency is equal to the current frequency only in oscillation center.On one side of the oscillation center,the voltage frequency is greater than the current frequency and on the other side,the voltage frequency is lower than the current frequency.Frequency differences between voltage frequency and current frequency depend on the oscillation period,electrical distance between measurement point and out-of-step unit and electromotive force angle of out-of-step units.A new oscillation identification method is proposed based on the frequency differences between electrical quantities.Wide-area measurements can be used to determine the location of oscillation center.Finally,the simulation results verify the correctness of the analysis.%重点研究了电力系统振荡时,振荡中心和非振荡中心电压频率和电流频率的特征。研究表明：当系统发生振荡时,只有振荡中心的电压频率与电流频率相等,且振荡中心的一侧电压频率大于电流频率,另一侧电压频率小于电流频率;电压频率与电流频率的差值大小取决于振荡周期的长短、测量点与失步机组的电气距离以及失步机组的电动势夹角。从而提出了一种新的基于电气量频率差异的振荡识别方法,同时通过广域信息的获取,可以判断出振荡中心的位置。仿真结果验证了分析的正确性。