新能源电力系统并网设备小扰动稳定分析(一):机理模型与稳定判据适用性

Small Signal Stability Analysis of Equipment in Renewable Energy Power System(PartⅠ):Mechanism Model and Adaptation of Stability Criterion

新能源电力系统的动态特性复杂,存在众多稳定分析方法及稳定判据。不同稳定方法/判据对应的物理解释和适用范围不同,目前难以从理论上回答各类判据适合解决的问题,以及它们所对应的物理解释是否合理。该文分为两部分,第一部分提出稳定判据的适用性评估方法,并尝试回答与稳定判据对应的物理解释是否合理;第二部分应用该方法分析部分典型判据的适用场合,并尝试给出其物理解释。第一部分首先回顾归纳现有稳定判据的推演机理,以及各判据背后对应的物理意义。其次,从稳定性等价、标称性和鲁棒性3个角度,提出稳定判据的适用性3个定性原则,并提出基于环路增益灵敏度的定量化指标。最后,以并网变流器为例,说明频域分析中若干基于阻抗的分析方法的性质,并探讨了其适用范围。电力系统中其他典型判据的适用性及其物理解释等工作将在第二部分展开探讨。

Many methods and criteria of stability assessment have been proposed due to the complex dynamics of renewable power system.The physical implications of these methods/criteria and their scopes of adaptation are different.It is difficult to theoretically answer that,for certain stability issue,which stability criterion is suitable and whether the corresponding physical interpretation is reasonable.This paper was divided into two parts.The methods for assessing the adaptation of stability criteria were put forward,and the question whether the corresponding physical interpretations were reasonable were answered in part I,while the adaptation of each stability criterion was analyzed by applying the method and the physical interpretation of each stability problem was derived in part II.In part I,the derivation process of the existing stability criteria and their underlying physical significance were reviewed at first.Secondly,the selection principles of stability criteria were proposed from 3 aspects,namely stability equivalence,nominal performance and robust stability.The quantitative index named loop gain sensitivity was also proposed.Finally,the adaptation of several impedance criteria of grid-connected converters were analyzed.It is shown that the nominal performance and robustness of these impedance criteria were not equivalent in frequency domain modal analysis.The adaptation of other typical stability criteria and the corresponding physical interpretation were analyzed in part II.