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        1 - Hierarchical Control for Accurate Power Sharing and Circulation Current Reduction in Resistive AC Microgrids Using Adaptive Virtual Impedance and Distributed Communication Links
        Masoud Esmaili Mohammad Hejri
        This paper presents an efficient method based on the adaptive virtual impedance and distributed communication link with a hierarchical control system in the resistive AC islanding micrigrids for accurate power sharing and circulating current reduction. In existing metho More
        This paper presents an efficient method based on the adaptive virtual impedance and distributed communication link with a hierarchical control system in the resistive AC islanding micrigrids for accurate power sharing and circulating current reduction. In existing methods, the adaptive virtual resistance can take negative values and violate the assumption of feeders’ resistive dominance based on which the droop controller is designed, and as a result, deteriorate its performance. Besides, the negative virtual resistance, with a reduction in the system overall damping, can reduce the stability margin and lead to side effects on the closed-loop system performance, especially during transients. In the proposed method, the problems associated with the negative virtual resistance are removed via the intelligent implementation of a new distributed communication link among microgrid inverters. The advantages of the proposed method include: circulating current elimination, accurate power sharing among distributed generators proportional to their rated capacities, prevention of voltage and frequency deviations from their reference values in point of power coupling (PCC) bus, guarantee of the resistive or inductive dominance of the feeder impedance in various operating points, decoupling between active and reactive powers, and as a result, guarantee of a desirable performance for droop controller in different operating points, performance and stability improvement, and finally using a simple, one-sided and a low bandwidth communication link instead of the complex, two-sided, and centralized communication system. Simulation results in MATLAB/SIMULINK environment demonstrate that the proposed control strategy has obviated effectively the shortcomings of the conventional droop and adaptive virtual impedance controllers. Manuscript profile
      • Open Access Article

        2 - Design of a Secondary Controller Based on Distributed Cooperative Control of Distributed Generators (DGs) with Multi-Agent Systems Approach Considering DoS Cyber Attacks
        Abdollah Mirzabeigi Ali Kazemy Mehdi Ramezani Seyed Mohammad Azimi
        Today, in many control methods, neighboring system information is used for better control and synchronization between different units, and therefore, in the access and transmission of information through communication links, problems such as disruption, uncertainty, noi More
        Today, in many control methods, neighboring system information is used for better control and synchronization between different units, and therefore, in the access and transmission of information through communication links, problems such as disruption, uncertainty, noise, delay, and cyber-attacks occur. In this paper, the effect of the Denial of Service (DoS) cyber-attack on the microgrid in island mode is investigated and a cooperative distributed hierarchical controller is designed with the presence of this cyber-attack. Distributed Generations (DGs) have been analyzed with the help of multi-agent systems and the communication network between them using graph theory. The effects of the DoS cyber-attack on the model of DGs are mathematically formulated and in proving the stability and synchronization of frequency and voltage, the suitable Lyapunov function is presented and the stability analysis of DGs against these cyber-attacks is performed and the stability and synchronization conditions of DGs are proved. To confirm the proposed theoretical issues, a case study model is simulated despite the DoS attack on the communicative links in Matlab Simulink, and the results show the performance of the designed controller in different conditions. Manuscript profile
      • Open Access Article

        3 - Stabilizing and Synchronizing the Islanded Microgrid with the Presence of Sensor and Actuator Fault and Cyber-Attack with Secondary Controller Design
        Abdollah Mirzabeigi Ali Kazemy Mehdi Ramezani Seyed Mohammad  Azimi
        In many microgrid control methods, the output information of sensors and actuators of neighbouring distributed generators (DGs) is used to stabilize and synchronize voltage and frequency. Many problems such as disturbances, uncertainty, unmodeled dynamics, cyber-attacks More
        In many microgrid control methods, the output information of sensors and actuators of neighbouring distributed generators (DGs) is used to stabilize and synchronize voltage and frequency. Many problems such as disturbances, uncertainty, unmodeled dynamics, cyber-attacks, noise, time delay, and measurement errors cause invalid data problems and errors in the system. Better microgrid control depends on the quality of data measured or sent from the output of sensors and actuators. In this paper, according to the advantages of the Cooperative distributed hierarchical control, it is used for control and synchronization in the islanded microgrid with the presence of sensor and actuator error. To synchronize DGs with multi-agent systems and communication channels, it is modeled with graph theory. To stabilize and synchronize, sensor and actuator error in the DG model is mathematically formulated. In the proof of stability and synchronization, the appropriate Lyapunov candidate is presented and the conditions of stability and synchronization are proved. Finally, to show the effectiveness of the designed controller in solving communication channel problems and verifying the presented theory, a case study is simulated in the MATLAB/Simulink software environment with the presence of error and cyber-attack of sensors and actuators. Manuscript profile
      • Open Access Article

        4 - Analysis of the Effects of Different Cyber Attacks on the Secondary Controller in Island Microgrids
        Abdollah Mirzabeigi ali kalantarnia
        With the advancement of science, in many control methods, the neighbor system is used to better control and synchronize between different information of microgrids. There are problems in accessing and transmitting information through communication links. In this article More
        With the advancement of science, in many control methods, the neighbor system is used to better control and synchronize between different information of microgrids. There are problems in accessing and transmitting information through communication links. In this article, vulnerability and acceptance of secondary control methods are distributed. Also, denial-of-service (DoS) cyber-attacks, sensors and actuators, and hijacking on the island microgrid have been investigated. In addition to stability, synchronization is also analyzed in this article. Multi-agent systems have been used for synchronization. Cyber-attacks are mathematically formulated in the controller. A suitable controller is designed to eliminate the attacks. In the stability and synchronization of frequency and voltage, the Lyapunov function is presented and simultaneous analysis of stability and synchronization has been done with practical proofs. The resilience factor has been calculated for different attacks. It is shown that the system is resilient against cyber-attacks. A case study has been simulated in MATLAB/Simulink to approve the theoretical issues. Manuscript profile