离散控制时间对暂态稳定性的反常影响及其机理

Anomalous Impact and Its Mechanism of Discrete Control Time on Transient Stability

大规模可再生能源与电力电子装备入网,以及交直流混联,使电力系统的动态特性更为复杂。文中利用扩展等面积准则(EEAC)对暂态稳定性的量化能力,分析诸如故障清除及切机等离散控制的时间对暂态功角稳定裕度的影响机理。暂态功角稳定裕度由主导映象的不平衡功率及功角构成的扩展相平面(P-δ)上的面积来表示,不但具有清晰的几何表示,也具有明确的物理意义。故可将控制时间对暂态功角稳定裕度的影响,分解为控制变量的P轴效应及δ轴效应。对于非哈密顿系统,可能出现与以往认知不符的现象,通过若干实例,验证了上述分析。

Since large-scale renewable energy and power electronic equipment accessing grids,as well as AC and DC hybrid connection,the dynamic characteristics of power systems become more complicated.Based on the quantitative ability of transient stability using extended equal area criterion(EEAC),the mechanism of the influence of discrete control time such as fault clearing time and generator-tripping time on the transient angle stability margin is analyzed in this paper.Transient angle stability margin is represented by the area on the extended phase plane(P-δ),which is composed of the unbalanced power and power angle of the dominant image.It not only shows clear geometric relationship,but also has clear physical meaning.Therefore,the impact of the control time on transient angle stability margin can be decomposed into P-axis andδ-axis effects of the control variable.For nonHamiltonian system,some phenomena inconsistent with the previous cognitions may exist.The above analysis is verified by several practical examples.