基于可变对称约束的大时延信息物理电力系统稳定性分析

Linear matrix inequality (LMI)-based delay-dependent stability analysis methods have been effectively utilized in the delayed cyber-physical power system (DCPPS). However, the significant computational burden associated with solving large-scale LMIs presents a substantial challenge when these methods are applied to real-world power systems. This article investigates an efficient evaluation method for the delay-dependent stability of the large DCPPS by presenting a variable symmetry constraints-based approach. First, by exploring the highly symmetric characteristics of control loops and renewable energy sources (RES), this article gives new structure restrictions for the weighting matrices required in the LMI-based stability criterion to reduce the number of decision variables (NDVs). In contrast, the existing methods focus only on the symmetric characteristics of traditional generators and are not applicable to large DCPPS integrated with the RES. Then, by introducing an adjustable parameter into the proposed structure restrictions, the approach based on variable symmetry constraints is established to bridge the gap where the existing constant methods fail to address the variable stability conditions. Moreover, the proposed variable symmetry constraints-based approach is more relaxed than the existing method since it keeps the NDVs in the LMIs unchanged despite massive generators equipped in the same control area of the DCPPS. Case studies are based on the large DCPPS with illustration of the load frequency control (LFC) schemes and the 39-Bus New England System to demonstrate the superiority of the proposed method. The proposed method is verified to be available to analyze the delay-dependent stability of the large-scale DCPPS efficiently while guaranteeing the computation accuracy.