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1. Cyber Physical Implementation of Improved Distributed Secondary Control of DC Microgrid

   https://doi.org/10.1109/icpee50452.2021.9358705  

   Pragallapati, Nataraj; Ranade, Satish J; Lavrova, Olga (January 2021, 2021 1st International Conference on Power Electronics and Energy (ICPEE))

   null (Ed.)

   This paper presents a cyber physical system implementation of an improved distributed secondary control (IDSC) scheme of islanded dc microgrid (DCMG). The IDSC scheme mitigates the hidden issues of primary control with included droop technique for the distributed generation unit (DGU) in a DCMG by providing the adjustable voltage compensation, improves voltage regulation and enhances the current sharing of all DGUs. The voltage compensation of IDSC is the resultant of two voltage components, i.e., average distributed integral voltage controller and average current controller. The dynamic consensus algorithm is used to obtain the global average values in the for distributed secondary controlusing relatively low bandwidth communication. The impact of communication time delay on the stability in IDSC based DCMG with two DGUs is presented. The performance of IDSC scheme is validated on a microgrid scenario, which includes parallel connection of four DGUs and common load. The real-time cyber physical system of DCMG is implemented on OP AL-RT test platform that combines the device layer on FPGA, control and cyber layers on CPU of OP5700 by using eFPGASim and RT-LAB. 

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2. RESILIENT CONTROL UNDER CYBER-ATTACKS IN CONNECTED ACC VEHICLES

   https://doi.org/10.1115/DSCC2019-9096  

   Jeon, W.; Zemouche, A; Rajamani, R (November 2019, Proceedings of the ASME Dynamic Systems and Control Conference)

   This paper focuses on the detection of cyber-attack on a communication channel and simultaneous radar health monitoring for a connected vehicle. A semi-autonomous adaptive cruise control (SA-ACC) vehicle is considered which has wireless communication with its immediately preceding vehicle to operate at small time-gap distances without creating string instability. However, the reliability of the wireless connectivity is critical for ensuring safe vehicle operation. The presence of two unknown inputs related to both sensor failure and cyber-attack seemingly poses a difficult estimation challenge. The dynamic system is first represented in descriptor system form. An observer with estimation error dynamics decoupled from the cyber-attack signal is developed. The performance of the observer is extensively evaluated in simulations. The estimation system is able to detect either a fault in the velocity measurement radar channel or a cyber-attack. Also, the proposed observer-based controller achieves resilient SA-ACC system under the cyber-attacks. The fundamental estimation algorithm developed herein can be extended in the future to enable cyber-attack detection in more complex connected vehicle architectures. 

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3. Mitigating Communication Delay Impact on Microgrid Stability Using a Compensator Based on Smith Predictor

   https://doi.org/10.1109/ECCE.2019.8913101  

   Haghighat, Hadi Akbari; Altin, Necmi; Nasiri, Adel (September 2019, IEEE Energy Conversion Conference and Expo)

   In this study, a control approach based on the model predictive control and Smith Predictor is proposed to compensate the effect of communication delay, and keep the stability of the Microgrid (MG) system. A cyber-physical model for the MG system is introduced to define and test the control and communication functions. The MG system consists of two distributed natural gas generators, an energy storage device, a PV system and a wind turbine with constant power. The Smith Predictor based delay compensator approach is applied to the defined MG based system. In addition, the impact of communication delay on MG is simulated and the behavior of the system with and without compensator is compared. The obtained simulation results show that the proposed approach can significantly decrease the impact of communication latency on frequency deviation and the response of the MG system. 

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4. Integrated instruction set randomization and control reconfiguration for securing cyber-physical systems

   https://doi.org/10.1145/3190619.3190636  

   Potteiger, Bradley; Zhang, Zhenkai; Koutsoukos, Xenofon (April 2018, HoTSoS '18 Proceedings of the 5th Annual Symposium and Bootcamp on Hot Topics in the Science of Security)

   Cyber-Physical Systems (CPS) have been increasingly subject to cyber-attacks including code injection attacks. Zero day attacks further exasperate the threat landscape by requiring a shift to defense in depth approaches. With the tightly coupled nature of cyber components with the physical domain, these attacks have the potential to cause significant damage if safety-critical applications such as automobiles are compromised. Moving target defense techniques such as instruction set randomization (ISR) have been commonly proposed to address these types of attacks. However, under current implementations an attack can result in system crashing which is unacceptable in CPS. As such, CPS necessitate proper control reconfiguration mechanisms to prevent a loss of availability in system operation. This paper addresses the problem of maintaining system and security properties of a CPS under attack by integrating ISR, detection, and recovery capabilities that ensure safe, reliable, and predictable system operation. Specifically, we consider the problem of detecting code injection attacks and reconfiguring the controller in real-time. The developed framework is demonstrated with an autonomous vehicle case study. 

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5. Detection and Mitigation of Data Manipulation Attacks in AC Microgrids

   https://doi.org/10.1109/TSG.2019.2958014  

   Mustafa, A; Poudel, B; Bidram, A; Modares, H. (December 2019, IEEE transactions on smart grid)

   This paper presents a resilient control framework for distributed frequency and voltage control of AC microgrids under data manipulation attacks. In order for each distributed energy resource (DER) to detect any misbehavior on its neighboring DERs, an attack detection mechanism is first presented using a Kullback-Liebler (KL) divergence-based criterion. An attack mitigation technique is then proposed that utilizes the calculated KL divergence factors to determine trust values indicating the trustworthiness of the received information. Moreover, DERs continuously generate a self-belief factor and communicate it with their neighbors to inform them of the validity level of their own outgoing information. DERs incorporate their neighbors' self-belief and their own trust values in their control protocols to slow down and mitigate attacks. It is shown that the proposed cyber-secure control effectively distinguishes data manipulation attacks from legitimate events. The performance of proposed secure frequency and voltage control techniques is verified through the simulation of microgrid tests system implemented on IEEE 34-bus test feeder with six DERs. 

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