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

    Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2022-05-29

    Abstract:

    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 is verified by using the proposed evaluation index. Secondly, the proposed evaluation index is used to analyze the oscillation of converters and DFIG, and the suitable stability criterion, derivation mechanism and dominant output variable are further discussed. Finally, a novel idea of equipment stability classification based on physical mechanism and dominant output variables are 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 are further explored.

    "