基于频率特征的失步解列判据原理

Out-of-step oscillation criterion based on frequency characteristics

重点研究了电力系统失步振荡时,两侧电动势幅值相等及不等情况下电压频率的特征。研究表明,当系统发生失步振荡时,不论两侧电动势幅值是否相等,电压频率都具有如下特征:振荡中心同一侧的电压频率同时增加或减小;振荡中心两侧的电压频率没有交集;且若振荡中心一侧电压频率增加,则另一侧电压频率减小,反之,则另一侧电压频率增加。提出一种新的基于频率特征的失步解列判据,该判据可以区分同步振荡和失步振荡,识别振荡中心的位置,同时不受系统结构变化和运行方式变化的影响。BPA仿真验证了分析的正确性。

The characteristics of voltage frequency during the out-of-step oscillation are researched for the conditions that the electromotive force amplitude of one side is equal and unequal to that of the other side,which shows that,under both conditions,the voltage frequencies at the same side of oscillation centre increase or decrease synchronously;the voltage frequencies of two sides have no intersection;the voltage frequencies of one side decrease while those of the other side increase.A criterion based on frequency characteristics is proposed for out-of-step oscillation,which,immune to system structure change and operating mode change,distinguishes the synchronous oscillation from the out-of-step oscillation and identifies the location of oscillation centre.Simulation on BPA verifies the correctness of the analysis.