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2021-06-24
Hastings, John C., Laverty, David M., Jahic, Admir, Morrow, D John, Brogan, Paul.  2020.  Cyber-security considerations for domestic-level automated demand-response systems utilizing public-key infrastructure and ISO/IEC 20922. 2020 31st Irish Signals and Systems Conference (ISSC). :1–6.
In this paper, the Authors present MQTT (ISO/IEC 20922), coupled with Public-key Infrastructure (PKI) as being highly suited to the secure and timely delivery of the command and control messages required in a low-latency Automated Demand Response (ADR) system which makes use of domestic-level electrical loads connected to the Internet. Several use cases for ADR are introduced, and relevant security considerations are discussed; further emphasizing the suitability of the proposed infrastructure. The authors then describe their testbed platform for testing ADR functionality, and finally discuss the next steps towards getting these kinds of technologies to the next stage.
2021-05-13
Liu, Xinghua, Bai, Dandan, Jiang, Rui.  2020.  Load Frequency Control of Multi-area Power Systems under Deception Attacks*. 2020 Chinese Automation Congress (CAC). :3851–3856.
This paper investigated the sliding mode load frequency control (LFC) for an multi-area power system (MPS) under deception attacks (DA). A Luenberger observer is designed to obtain the state estimate of MPS. By using the Lyapunov-Krasovskii method, a sliding mode surface (SMS) is designed to ensure the stability. Then the accessibility analysis ensures that the trajectory of the MPS can reach the specified SMS. Finally, the serviceability of the method is explained by providing a case study.
2021-03-17
Kushal, T. R. B., Gao, Z., Wang, J., Illindala, M. S..  2020.  Causal Chain of Time Delay Attack on Synchronous Generator Control. 2020 IEEE Power Energy Society General Meeting (PESGM). :1—5.

Wide integration of information and communication technology (ICT) in modern power grids has brought many benefits as well as the risk of cyber attacks. A critical step towards defending grid cyber security is to understand the cyber-physical causal chain, which describes the progression of intrusion in cyber-space leading to the formation of consequences on the physical power grid. In this paper, we develop an attack vector for a time delay attack at load frequency control in the power grid. Distinct from existing works, which are separately focused on cyber intrusion, grid response, or testbed validation, the proposed attack vector for the first time provides a full cyber-physical causal chain. It targets specific vulnerabilities in the protocols, performs a denial-of-service (DoS) attack, induces the delays in control loop, and destabilizes grid frequency. The proposed attack vector is proved in theory, presented as an attack tree, and validated in an experimental environment. The results will provide valuable insights to develop security measures and robust controls against time delay attacks.

2021-03-15
Shahkar, S., Khorasani, K..  2020.  A Resilient Control Against Time-Delay Switch and Denial of Service Cyber Attacks on Load Frequency Control of Distributed Power Systems. 2020 IEEE Conference on Control Technology and Applications (CCTA). :718—725.

A time-delay switch (TDS) cyber attack is a deliberate attempt by malicious adversaries aiming at destabilizing a power system by impeding the communication signals to/from the centralized controller from/to the network sensors and generating stations that participate in the load frequency control (LFC). A TDS cyber attack can be targeting the sensing loops (transmitting network measurements to the centralized controller) or the control signals dispatched from the centralized controller to the governor valves of the generating stations. A resilient TDS control strategy is proposed and developed in this work that thwarts network instabilities that are caused by delays in the sensing loops, and control commands, and guarantees normal operation of the LFC mechanism. This will be achieved by augmenting the telemetered control commands with locally generated feedback control laws (i.e., “decentralized” control commands) taking measurements that are available and accessible at the power generating stations (locally) independent from all the telemetered signals to/from the centralized controller. Our objective is to devise a controller that is capable of circumventing all types of TDS and DoS (Denial of Service) cyber attacks as well as a broad class of False Data Injection (FDI) cyber attacks.

2021-02-16
Siu, J. Y., Panda, S. Kumar.  2020.  A Specification-Based Detection for Attacks in the Multi-Area System. IECON 2020 The 46th Annual Conference of the IEEE Industrial Electronics Society. :1526—1526.
In the past decade, cyber-attack events on the power grid have proven to be sophisticated and advanced. These attacks led to severe consequences on the grid operation, such as equipment damage or power outages. Hence, it is more critical than ever to develop tools for security assessment and detection of anomalies in the cyber-physical grid. For an extensive power grid, it is complex to analyze the causes of frequency deviations. Besides, if the system is compromised, attackers can leverage on the frequency deviation to bypass existing protection measures of the grid. This paper aims to develop a novel specification-based method to detect False Data Injection Attacks (FDIAs) in the multi-area system. Firstly, we describe the implementation of a three-area system model. Next, we assess the risk and devise several intrusion scenarios. Specifically, we inject false data into the frequency measurement and Automatic Generation Control (AGC) signals. We then develop a rule-based method to detect anomalies at the system-level. Our simulation results proves that the proposed algorithm can detect FDIAs in the system.
2021-02-08
Liu, S., Kosuru, R., Mugombozi, C. F..  2020.  A Moving Target Approach for Securing Secondary Frequency Control in Microgrids. 2020 IEEE Canadian Conference on Electrical and Computer Engineering (CCECE). :1–6.
Microgrids' dependency on communication links exposes the control systems to cyber attack threats. In this work, instead of designing reactive defense approaches, a proacitve moving target defense mechanism is proposed for securing microgrid secondary frequency control from denial of service (DoS) attack. The sensor data is transmitted by following a Markov process, not in a deterministic way. This uncertainty will increase the difficulty for attacker's decision making and thus significantly reduce the attack space. As the system parameters are constantly changing, a gain scheduling based secondary frequency controller is designed to sustain the system performance. Case studies of a microgrid with four inverter-based DGs show the proposed moving target mechanism can enhance the resiliency of the microgrid control systems against DoS attacks.
2020-12-11
Han, Y., Zhang, W., Wei, J., Liu, X., Ye, S..  2019.  The Study and Application of Security Control Plan Incorporating Frequency Stability (SCPIFS) in CPS-Featured Interconnected Asynchronous Grids. 2019 IEEE Innovative Smart Grid Technologies - Asia (ISGT Asia). :349—354.

The CPS-featured modern asynchronous grids interconnected with HVDC tie-lines facing the hazards from bulk power imbalance shock. With the aid of cyber layer, the SCPIFS incorporates the frequency stability constrains is put forwarded. When there is bulk power imbalance caused by HVDC tie-lines block incident or unplanned loads increasing, the proposed SCPIFS ensures the safety and frequency stability of both grids at two terminals of the HVDC tie-line, also keeps the grids operate economically. To keep frequency stability, the controllable variables in security control strategy include loads, generators outputs and the power transferred in HVDC tie-lines. McCormick envelope method and ADMM are introduced to solve the proposed SCPIFS optimization model. Case studies of two-area benchmark system verify the safety and economical benefits of the SCPFS. HVDC tie-line transferred power can take the advantage of low cost generator resource of both sides utmost and avoid the load shedding via tuning the power transferred through the operating tie-lines, thus the operation of both connected asynchronous grids is within the limit of frequency stability domain.

Ma, X., Sun, X., Cheng, L., Guo, X., Liu, X., Wang, Z..  2019.  Parameter Setting of New Energy Sources Generator Rapid Frequency Response in Northwest Power Grid Based on Multi-Frequency Regulation Resources Coordinated Controlling. 2019 IEEE 8th International Conference on Advanced Power System Automation and Protection (APAP). :218—222.
Since 2016, the northwest power grid has organized new energy sources to participate in the rapid frequency regulation research and carried out pilot test work at the sending end large power grid. The experimental results show that new energy generator has the ability to participate in the grid's rapid frequency regulation, and its performance is better than that of conventional power supply units. This paper analyses the requirements for fast frequency control of the sending end large power grid in northwest China, and proposes the segmented participation indexes of photovoltaic and wind power in the frequency regulation of power grids. In accordance with the idea of "clear responsibilities, various types of unit coordination", the parameter setting of new energy sources rapid frequency regulation is completed based on the coordinated control based on multi-frequency regulation resources in northwest power grid. The new energy fast frequency regulation model was established, through the PSASP power grid stability simulation program and the large-scale power grid stability simulation analysis was completed. The simulation results show that the wind power and photovoltaic adopting differential rapid frequency regulation parameters can better utilize the rapid frequency regulation capability of various types of power sources, realize the coordinated rapid frequency regulation of all types of units, and effectively improve the frequency security prevention and control level of the sending end large power grid.
2020-10-06
Jacobs, Nicholas, Hossain-McKenzie, Shamina, Vugrin, Eric.  2018.  Measurement and Analysis of Cyber Resilience for Control Systems: An Illustrative Example. 2018 Resilience Week (RWS). :38—46.

Control systems for critical infrastructure are becoming increasingly interconnected while cyber threats against critical infrastructure are becoming more sophisticated and difficult to defend against. Historically, cyber security has emphasized building defenses to prevent loss of confidentiality, integrity, and availability in digital information and systems, but in recent years cyber attacks have demonstrated that no system is impenetrable and that control system operation may be detrimentally impacted. Cyber resilience has emerged as a complementary priority that seeks to ensure that digital systems can maintain essential performance levels, even while capabilities are degraded by a cyber attack. This paper examines how cyber security and cyber resilience may be measured and quantified in a control system environment. Load Frequency Control is used as an illustrative example to demonstrate how cyber attacks may be represented within mathematical models of control systems, to demonstrate how these events may be quantitatively measured in terms of cyber security or cyber resilience, and the differences and similarities between the two mindsets. These results demonstrate how various metrics are applied, the extent of their usability, and how it is important to analyze cyber-physical systems in a comprehensive manner that accounts for all the various parts of the system.

Bidram, Ali, Damodaran, Lakshmisree, Fierro, Rafael.  2019.  Cybersecure Distributed Voltage Control of AC Microgrids. 2019 IEEE/IAS 55th Industrial and Commercial Power Systems Technical Conference (I CPS). :1—6.

In this paper, the cybersecurity of distributed secondary voltage control of AC microgrids is addressed. A resilient approach is proposed to mitigate the negative impacts of cyberthreats on the voltage and reactive power control of Distributed Energy Resources (DERs). The proposed secondary voltage control is inspired by the resilient flocking of a mobile robot team. This approach utilizes a virtual time-varying communication graph in which the quality of the communication links is virtualized and determined based on the synchronization behavior of DERs. The utilized control protocols on DERs ensure that the connectivity of the virtual communication graph is above a specific resilience threshold. Once the resilience threshold is satisfied the Weighted Mean Subsequence Reduced (WMSR) algorithm is applied to satisfy voltage restoration in the presence of malicious adversaries. A typical microgrid test system including 6 DERs is simulated to verify the validity of proposed resilient control approach.

2020-07-16
Bovo, Cristian, Ilea, Valentin, Rolandi, Claudio.  2018.  A Security-Constrained Islanding Feasibility Optimization Model in the Presence of Renewable Energy Sources. 2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I CPS Europe). :1—6.

The massive integration of Renewable Energy Sources (RES) into power systems is a major challenge but it also provides new opportunities for network operation. For example, with a large amount of RES available at HV subtransmission level, it is possible to exploit them as controlling resources in islanding conditions. Thus, a procedure for off-line evaluation of islanded operation feasibility in the presence of RES is proposed. The method finds which generators and loads remain connected after islanding to balance the island's real power maximizing the amount of supplied load and assuring the network's long-term security. For each possible islanding event, the set of optimal control actions (load/generation shedding) to apply in case of actual islanding, is found. The procedure is formulated as a Mixed Integer Non-Linear Problem (MINLP) and is solved using Genetic Algorithms (GAs). Results, including dynamic simulations, are shown for a representative HV subtransmission grid.

Ding, Yueming, Li, Kuan, Meng, Zhaoxian.  2018.  CPS Optimal Control for Interconnected Power Grid Based on Model Predictive Control. 2018 2nd IEEE Conference on Energy Internet and Energy System Integration (EI2). :1—9.

The CPS standard can be more objective to evaluate the effect of control behavior in each control area on the interconnected power grid. The CPS standard is derived from statistical methods emphasizing the long-term control performance of AGC, which is beneficial to the frequency control of the power grid by mutual support between the various power grids in the case of an accident. Moreover, CPS standard reduces the wear of the equipment caused by the frequent adjustment of the AGC unit. The key is to adjust the AGC control strategy to meet the performance of CPS standard. This paper proposed a dynamic optimal CPS control methodology for interconnected power systems based on model predictive control which can achieve optimal control under the premise of meeting the CPS standard. The effectiveness of the control strategy is verified by simulation examples.

2019-11-04
Wang, Jingyuan, Xie, Peidai, Wang, Yongjun, Rong, Zelin.  2018.  A Survey of Return-Oriented Programming Attack, Defense and Its Benign Use. 2018 13th Asia Joint Conference on Information Security (AsiaJCIS). :83-88.

The return-oriented programming(ROP) attack has been a common access to exploit software vulnerabilities in the modern operating system(OS). An attacker can execute arbitrary code with the aid of ROP despite security mechanisms are involved in OS. In order to mitigate ROP attack, defense mechanisms are also drawn researchers' attention. Besides, research on the benign use of ROP become a hot spot in recent years, since ROP has a perfect resistance to static analysis, which can be adapted to hide some important code. The results in benign use also benefit from a low overhead on program size. The paper discusses the concepts of ROP attack as well as extended ROP attack in recent years. Corresponding defense mechanisms based on randomization, frequency, and control flow integrity are analyzed as well, besides, we also analyzed limitations in this defense mechanisms. Later, we discussed the benign use of ROP in steganography, code integrity verification, and software watermarking, which showed the significant promotion by adopting ROP. At the end of this paper, we looked into the development of ROP attack, the future of possible mitigation strategies and the potential for benign use.

2015-05-05
Popli, N., Ilic, M.D..  2014.  Storage devices for automated frequency regulation and stabilization. PES General Meeting | Conference Exposition, 2014 IEEE. :1-5.

In this paper we propose a framework for automating feedback control to balance hard-to-predict wind power variations. The power imbalance is a result of non-zero mean error around the wind power forecast. Our proposed framework is aimed at achieving the objective of frequency stabilization and regulation through one control action. A case-study for a real-world system on Flores island in Portugal is provided. Using a battery-based storage on the island, we illustrate the proposed control framework.
 

2015-05-04
Tennyson, M.F., Mitropoulos, F.J..  2014.  Choosing a profile length in the SCAP method of source code authorship attribution. SOUTHEASTCON 2014, IEEE. :1-6.

Source code authorship attribution is the task of determining the author of source code whose author is not explicitly known. One specific method of source code authorship attribution that has been shown to be extremely effective is the SCAP method. This method, however, relies on a parameter L that has heretofore been quite nebulous. In the SCAP method, each candidate author's known work is represented as a profile of that author, where the parameter L defines the profile's maximum length. In this study, alternative approaches for selecting a value for L were investigated. Several alternative approaches were found to perform better than the baseline approach used in the SCAP method. The approach that performed the best was empirically shown to improve the performance from 91.0% to 97.2% measured as a percentage of documents correctly attributed using a data set consisting of 7,231 programs written in Java and C++.

2015-04-30
Sridhar, S., Govindarasu, M..  2014.  Model-Based Attack Detection and Mitigation for Automatic Generation Control. Smart Grid, IEEE Transactions on. 5:580-591.

Cyber systems play a critical role in improving the efficiency and reliability of power system operation and ensuring the system remains within safe operating margins. An adversary can inflict severe damage to the underlying physical system by compromising the control and monitoring applications facilitated by the cyber layer. Protection of critical assets from electronic threats has traditionally been done through conventional cyber security measures that involve host-based and network-based security technologies. However, it has been recognized that highly skilled attacks can bypass these security mechanisms to disrupt the smooth operation of control systems. There is a growing need for cyber-attack-resilient control techniques that look beyond traditional cyber defense mechanisms to detect highly skilled attacks. In this paper, we make the following contributions. We first demonstrate the impact of data integrity attacks on Automatic Generation Control (AGC) on power system frequency and electricity market operation. We propose a general framework to the application of attack resilient control to power systems as a composition of smart attack detection and mitigation. Finally, we develop a model-based anomaly detection and attack mitigation algorithm for AGC. We evaluate the detection capability of the proposed anomaly detection algorithm through simulation studies. Our results show that the algorithm is capable of detecting scaling and ramp attacks with low false positive and negative rates. The proposed model-based mitigation algorithm is also efficient in maintaining system frequency within acceptable limits during the attack period.