Distributed Predictive Load Frequency Control Of Interconnected Power System Based On Event-triggered

With the increasingly prominent issue of reverse distribution of energy and load demand in China,the interconnection of power systems has become an effective method to ensure regional power supply and green development needs.However,cross regional interconnection of power systems makes the grid structure more complex and increases the amount of data transmitted between regions,which bings new challenges to the safe and stable operation of power systems.Load frequency control(LFC)is one of the important control methods to ensure the safe,reliable,and economic operation of power systems.In view of this,based on the theory of event-triggered and distributed model predictive control(DMPC),this paper proposes a load frequency control scheme for multi-area interconnected power systems to solve the problems of system frequency fluctuations and computational burden.The main research work of this article is summarized as follows:(1)Based on the generation characteristics of thermal power units,the mathematical model of load frequency control system for multi-area interconnected power systems is established.Then,the problem description of load frequency control is provided.(2)Considering the limitations of computing resources in multi-area interconnected power systems,this paper proposes an event triggered distributed model predictive control(ET-DMPC)method.Based on asynchronous communication information to estimate the future behavior of the coupled subsystem,and the distributed optimization problem is designed using a prediction model containing the estimated information of the coupled subsystem.Next,according to the error between the actual state trajectory and the optimal predicted state trajectory of the system,event-triggered condition is designed to determine the triggering time for solving the optimization problem,and it is theoretically proved that the designed triggering conditions can avoid the Zeno phenomenon.Then,the feasibility of the algorithm and the stability of the closed-loop system are analyzed based on Lyapunov stability theory.Finally,the simulation results of a three area interconnected power system show that,compared to the time triggered DMPC algorithm,the designed ET-DMPC algorithm not only meets the frequency modulation requirements,but also greatly reduces the computational burden of the system.At the same time,ET-DMPC has good robustness when the model parameters are uncertain.(3)Aiming at the problem that the continuous event triggering mechanism requires specific hardware devices to continuously detect the actual state of the system,this paper proposes a periodic event triggered distributed model predictive control(PET-DMPC)algorithm.This triggered mechanism combines traditional periodic sampling control with event triggered control.Each subsystem detects event triggered conditions based on actual state measured at each sampling time.When the triggering conditions are satisfied,the subsystem generates an estimated state trajectory of the neighbor system based on the interactive information,and solves optimization problems to achieve coordinated control of the entire system.Finally,the simulation results of a three-areas interconnected power system show that the proposed PET-DMPC method achieves frequency modulation while satisfying the generator rate of change constraints and control input constraints,and reduces the computational burden.