A Novel Distributed-Decentralized Fixed-Time Optimal Frequency and Excitation Control Framework in a Nonlinear Network-Preserving Power System

A novel distributed-decentralized fixed-time optimal frequency and excitation (Di-De-FTOFE) control framework in a network-preserving power system with nonlinear power flow is proposed in this paper. Firstly, to obtain the solution of the economic dispatch (ED) problem, the proposed control framework contains the distributed fixed-time consensus-based optimal frequency (Di-FTCOF) control to make the Lagrange multiplier of each generation reach consensus in a fixed time and the decentralized fixed-time excitation (De-FTE) control to ensure the power system frequency back to the rated value in a fixed time for satisfying the load-generation balance constraints of ED problem. Secondly, the voltage dynamic also can be maintained around the rated value by the designed De-FTE control which owns good universality to coordinate other optimal frequency control methods. Thirdly, the Di-De-FTOFE control framework is robust to communication failure through the self-adaptive adjustment, which is both analyzed in the theoretical verification and simulation. Finally, the performance of the Di-De-FTOFE control framework is evaluated in simulation with several adverse situations, such as load decrease/increase and communication failure.