Research On Distributed Secondary Control Strategies Against False Data Injection Attacks For Microgrid

The continuous integration of distributed generators(DGs)with renewable energy as the main energy has brought many problems to the security and stability of the power grid.To solve the problems caused by numerous,dispersed located and diverse form of DGs,many control theories have been applied to microgrid.Compared with centralized control,distributed control is more suitable for microgrid to manage the distributed located DGs due to its decentralization,scalability and high reliability.However,the distributed control,which more relies on communication network,makes microgrid easily expose to cyber attack threats.Among the cyber attacks,false data injection attack(FDIA)is a kind of common and stealthy attack,which disturbs the control target by tampering with the data of the control system and further destroys the stability of microgrid.To this end,this thesis studies how to mitigate or eliminate the adverse effects of FDIAs by designing attack-resilient distributed control algorithm.The main contribution of this thesis can be summarized as follows:(1)the distributed secondary control of microgrid is improved.Based on the definition of CPS model of microgrid,the basic principles of the primary control and the secondary control of microgrid are introduced.By comparing the disadvantages of centralized secondary control strategy,this thesis shows how to use the distributed cooperative control theory to realize the distributed secondary control of microgrid.After that,a fast convergent distributed dynamic average consensus(DDAC)without rate measurements is proposed to evaluate the total dynamic load of microgrid in a distributed manner,with which the distributed secondary control of microgrid is improved.(2)the FDIAs attack-resilient distributed secondary control strategies of microgrid are proposed.The models of FDIAs on measurement devices,controllers and communication links are established,and the influences of FDIAs on the control system are analyzed based on these FDIAs models.For the situation where the controller being attacked by constant FDIAs,an attack-elimination secondary control algorithm is proposed,which can deal with the situation that all DGs are attacked.For the situation where all vulnerable locations(measurement device,controller and communication link)are subject to bounded FDIAs,a hidden-layer based attackresilient distributed control algorithm is proposed,which mitigates the adverse effects of bounded FDIAs by designing the system and setting the parameters.These algorithms improve the resilience of microgrid CPS for FDIAs.(3)the event-triggered distributed secondary control strategies are proposed,and the ability of event-triggered mechanism to resist FDIAs is preliminarily explored.Based on the conventional distributed secondary control strategy of microgrid,a trigger function is derived.An event-triggered distributed secondary control is proposed by using this trigger function and designing trigger conditions.Then,by further improving the trigger function,a fully distributed event-triggered distributed secondary control strategy is proposed.After that,the upper limit of the trigger condition check period is derived,the exponential convergence of the algorithm is proved as well.Finally,based on the aperiodic and intermittent communication mode of event-triggered distributed secondary control strategy,a timely and accurate detection and elimination method for successive FDIAs on the communication links is proposed,which protects the communication network of distributed secondary control from FDIAs.