利用联络线功率相对相位判定低频振荡模式

提出一种在线判定大规模电力系统低频振荡模式的新方法。将发电机的有功功率与转速表示为广义相量的形式，推导了两者相位之间的关系，通过一个简单算例阐明了联络线功率振荡增量的相对相位与振荡模式之间的关系，指出不同的振荡模式对应着不同的相位组合，从而可以通过考察相位组合来判定振荡模式。利用PSS/E分析澳大利亚东南部电力系统的小信号稳定性，验证了相位组合与模式之间的对应关系不随工况与模型详细程度而变化。给出了在实际系统中使用本方法的步骤，并对华东电网进行了验算。结果表明，所提出的方法能够在线判定低频振荡模式，对大规模电力系统低频振荡的监测是有价值的。

Low Frequency Oscillation Mode Determination Based on Relative Phases of the Tie-line Active Powers

This paper proposed a new algorithm to perform the online determination of the low frequency oscillation modes in large interconnected power system. First, the generator’s active power and its speed deviation were represented in the form of generalized phasor and the relationship between their phase angles was deduced. Then a simple system was constructed to illustrate the correlations between the power oscillation flows in the tie lines and the low frequency oscillation modes. Theoretical analysis indicates that different oscillation modes correspond to different phase angle combinations, and vice versa. The small signal stability of the SE Australian power system was analyzed by PSS/E. The analysis reveals that both of the operating point and the degree of detail in modeling has essentially no effect on the corresponding relationship between oscillation modes and phase angle combinations. Finally the procedure to use the algorithm in practical power system was given, and it was applied to the Eastern China power grid. Results indicate that the algorithm proposed by this paper is able to determine the low frequency oscillation modes online and is helpful for the monitoring of low frequency oscillation.