不确定负荷下小干扰稳定的区间分析方法

An Interval Analysis Method of Small-signal Stability Considering Load Uncertainty

计及负荷的不确定性,提出了区间负荷下的小干扰稳定区间分析方法。基于增广矩阵的灵敏度求解,推导了振荡模式的阻尼比对负荷有功的灵敏度指标。以负荷灵敏度指标为指导,通过迭代搜索求解了典型负荷水平下关键振荡模式的阻尼比区间极值,进而可以确定区间负荷下的阻尼比区间分布,并据此可推断特征值阻尼比随负荷变化的规律,提供更加全面的稳定性信息。通过4机系统和新英格兰39节点系统的算例实现,验证了该方法的有效性,与蒙特卡罗模拟法的结果对比,表明了该方法计算结果的正确性和计算速度上的优越性。

Considering load uncertainty, an interval analysis method of small-signal stability is presented when the load is expressed as an interval number. Based on the eigen-sensitivity of augmented matrix, the sensitivity of the eigenvalue damping ratio with respect to the active load power is derived. By using the guide of the sensitivity, the damping ratio extreme values of weak oscillation modes are solved by iterative search method under typical load levels, and the damping ratio distribution in the whole load range can be further determined. Accordingly the characteristics of damping ratio changes with respect to load variations can be obtained, so that the more comprehensive stability information can be provided. Finally, the validity and applicability of this method are proven through a 4-machine system and the New England 39-bus system. Comparison results illustrate that the method proposed is correct and superior to the Monte Carlo simulation method on the calculation speed.