新能源电力系统并网设备小扰动稳定分析(二):导出机理与稳定性分类探讨

Small Signal Stability Analysis of Grid-connected Equipment in Power System(Part Ⅱ):Discussion on Mechanism Derivation and Classification of Stability

该文第一部分从稳定性等价、标称性和鲁棒性3个角度,提出稳定分析方法/判据适应性的定性原则和量化评估指标。第二部分将进一步针对同步机、变流器和双馈机组等典型设备,分析现有稳定判据的适用性及判据对应的失稳物理解释是否合理,并从主导输出变量角度探讨稳定问题的分类方法。首先,利用所提评估指标,验证现有同步机低频振荡和次同步振荡/谐振的稳定分析方法和物理解释的合理性;其次,利用所提评估指标分析变流器和双馈机组振荡问题,探讨其适用的稳定判据、导出机理及主导输出变量;最后,提出基于物理机理及主导输出变量的设备稳定性分类新思路,从矢量角度将设备稳定性分为相角主导的同步稳定、幅值主导的电压稳定和它们特殊组合而成的电气谐振3类。同时还探讨宽频带振荡概念、设备稳定和系统稳定间的联系及稳定性分类的可拓展性等问题。

From the perspective of stability equivalence,nominal performance and robustness,the qualitative principles and quantitative evaluation index of stability criterion adaptation are proposed in Part Ⅰ.In addition,the adaptation of the existing stability criteria and the physical interpretation of instability corresponding to the suitable stability criterion are analyzed for the typical equipment in power system,such as synchronous machines,doubly-fed induction generators(DFIG) and converters in Part Ⅱ.Thereby the stability classification of the renewable power system is discussed based on dominant output variable.Firstly,aiming at low-frequency and sub-synchronous oscillation/resonance(SSO/SSR) of synchronous machine,the rationality of the existing stability analysis methods and physical interpretation was verified by using the proposed evaluation index.Secondly,the proposed evaluation index was used to analyzed the oscillation of converters and DFIG,and the suitable stability criterion,derivation mechanism and dominant output variable werre further discussed.Finally,a novel idea of equipment stability classification based on physical mechanism and dominant output variables were proposed,which classifies equipment stability from the vector perspective into three categories:phase-dominated synchronous stability,amplitude-dominated voltage stability,and electrical resonance formed by their special combination.Issues such as the concept of wide-band oscillation,the distinction between equipment stability and system stability,and the extensibility of their classification were further explored.