Robust Load Frequency Control for Uncertain Multi-area Power Systems with Coupling of System Dynamics and Reconfigurable Communication Networks: Network Switching, Automatic Decision and Gain Schedule

This article focuses on the challenging problems for robust load frequency control (RLFC) in multi-area power systems considering unknown parameter uncertainties in both load frequency control (LFC) operation conditions of nominal power systems and coupling inputs under dynamically changing reconfigurable communication networks by developing an autonomous gain scheduling scheme. We consider a class of coupled smart grids (e.g., multi-energy coupling microgrids as a modern multi-area multi-source power system that can realize multi-energy complementarity and comprehensive utilization improving energy efficiency) in which the process dynamics are composed of time-varying vector functions of scalar combinations of the states and dynamically changing networks. By incorporating the impact of generation-rate constraints (GRC), we propose a performance estimation index to evaluate and determine the optimal configuration of communication networks in multi-area power systems. In the event of link failures due to interference or when partial limits exceed predefined security redundancy, the automatic decision function is activated, scheduling reconfigurable communication modes and adjusting controller gains accordingly. Based on this, we first develop an RLFC strategy via a distributed framework that is driven by a dynamically reconfigurable communication network and a time-varying switching scheme. The proposed strategy can handle the system coupling dynamics to achieve global exponential stability for multi-area power systems with multiple aggregated uncertainties and GRC limiters. Furthermore, an RLFC strategy via an exponentially distributed adaptive framework is proposed to schedule the control gains and manage time-varying adaptive coupling dynamics for the multi-area power systems with multiple GRC limiters and aggregated system uncertainties. These uncertainties consist of aggregated parameter uncertainties, coexisting matched, and mismatched parameter uncertainties that can be unknown, where the continuous excitation conditions are equivalent to matrix inequality conditions to ensure exponential stability at the origin. The effectiveness of the proposed strategies is verified via a three-area power system with dynamically changing configurable communication networks.