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Security and Reliability Perspectives in Cyber-Physical Smart Grids
Abstract
Information and communication technologies (ICTs) are widely deployed in electric power systems to improve system monitoring, control, protection, and data processing capabilities. However, power systems’ dependency on cyber infrastructure inevitably increases the risk of system degradation resulting from cyber-attacks. In addition, the intrinsic failures of cyber elements and the design defects of cyber-physical system architecture affect power system reliability. These two concerns are generally termed as "cyber-physical security" and "cyber-physical reliability", respectively. While the two topics have received considerable research efforts in recent years, their distinctions still remain obscure among researchers. This paper succinctly summarizes the scopes, approaches, and major advancements in the two research areas with representative examples provided to clarify their distinctions. By revealing the inherent features of cyber-physical security and cyber-physical reliability in smart grids, this paper is written with the objective of facilitating future studies in these two areas.
... The current development of information technology leads to a rapid increase in the number of users and volumes of processed data, increasing the requirements for speed and reliability of functioning of individual components of information and computer systems, emergence of new forms and methods for implementing various cybernetic threats [1][2][3][4][5][6][7]. Particularly acute in this sense are the issues of cybersecurity of modern Smart Grids [8][9][10][11][12]. For example, due to only one cyberattack on the energy systems of Ukraine with the use of malicious software such as BlackEnergy, on the evening of December 23, 2015, 27 substations and 103 settlements were disconnected from the power supply network [13,14]. ...
... Another example of functional safety impairment is the effect of the computer virus Petya.A (which is a variant of the WannaCry virus) in the summer of 2017, which has affected the information systems of the National Bank of Ukraine, Ukrposhta, Ukrzaliznytsia, a number of state and commercial banks, including Sberbank, power companies, airports, industrial facilities, TV and radio companies, etc. [15,16]. Therefore, the issue of providing cybersecurity of distributed information and communication systems in the context of possible implementation of various cybernetic threats is extremely important, they are directly related to the construction of reliable and secure Smart Grids [1,10]. ...
... Under the influence of malware, individual communication and computing components can be transferred to unauthorized modes of operation, leading to failures, various violations of the established procedure for their use, destruction, distortion, blocking, unauthorized leakage of processed and transmitted information, as well as disruption of the methods and algorithms of routing between nodes of telecommunication system [1,4,22]. Consequently, the development and study of methods for monitoring network activity, technologies for detecting malicious software and preventing its impact on protected information and communication resources is an actual scientific and applied problem, its solution is directly related to ensuring the security of modern telecommunications systems and networks and computer technologies used [1,10]. ...
... The IoE, unlike IoE, is one of the primary methods that monitors and controls the flow and distribution of equal amount of energy within the SG [3,15]. [11], [1], [2], [16], [7], [10] General overview of the SG infrastructure ✓ × ✓ × ✓ ✓ [9], [12], [3], [13], [14], [17], [4] Distributed network model with energy management systems [19], [5], [20], [8], [6] Communication architecture in SG network ...
... Figure 7 shows the different levels of communication architecture in SG network. This architecture consists of three tires such as access tire, distribution tire and core tire, and are explained in detail in the following subsections [19,42]: ...
Currently, there is a huge production in the automotive industries and energy consumption resulted into spike in the costand emissions of greenhouse gases. Hence, an efficient energy utilization mechanism has become a prime most important factor. Energy and its conservation problem also have raised and become one of the prominent critical factors needed to address.Therefore, the development of smartgrid infrastructure is one of the solution to address the above issue. In this article, different methods and mechanisms require to manage energy efficiently within the smartgrid network using communication technologies and protocols has been discussed. Proposed an integration method of electric vehicles and smartgrid using communicationnet-works for charging or discharging electricity and exchanging relevant information. Inaddition, in this paper we discuss different integration strategies and multi-agent system implementation in the smartgrid network.The proposed multi-agent system shows the efficient method for monitoring powerflow and maintaining the stability of the grid. The paper also present the optimal scheduling of charging of electric vehicles in the smartgrid network.Finally, investigated and presented many standard communication protocols and their comparisons with respect to different scenarios.
... Attacks on SG systems range from changing the values of the smart meters to corrupting system utilities. For example, an attacker can corrupt the energy and usage data collected by the smart meters to reduce or increase the bills for artificial energy consumption values [15]. ...
... The researchers dynamically discussed and settled on the aims of the review prior to and during the course of the review process. To limit reviewer bias, each paper was reviewed independently by three reviewers while incorporating the inclusion and 15 21 Frequency of threats mitigation Frequency exclusion criteria, and then another round of verification was applied by the three reviewers, to resolve any conflicting results. The main motive was to make sure that the reviewers had similar interpretations of the inclusion and exclusion criteria, which implies that there was a similar understanding of the inclusion and exclusion criteria. ...
Smart Grid (SG) is a major electricity trend expected to replace traditional electricity systems. SG has faster response to electricity malfunctions and improved utilization of consumed power, and it has two-way communication between providers and consumers. However, SG is vulnerable to attacks and requires robust authentication techniques to provide secure authenticity for its components. This paper analyses previous literature, comprising 27 papers on the status of SG authentication techniques, main components, and kinds of attacks. This paper also highlights the main requirements and challenges for developing authentication approaches for the SG system. This can serve as useful guidance for the development and deployment of authentication techniques for SG systems and helps practitioners select authentication approaches applicable to system needs.
... For example, Intrusion Detection and Prevention Systems [39][40][41][42] are also can be built using some elements of artificial intelligence. Critically important information systems in different spheres, including banking, industrial facilities management and Smart Grids are especially interesting for further research [43][44][45][46][47][48][49][50]. ...
... To assign the incentive, the decision must be fair and reliable. Similarly, for the timely exchange of messages in a successful manner, the specifications of a communication system determine the reliability [113]. The specifications associated with reliability would vary across different SG applications. ...
Smart grids (SG) are electricity grids that communicate with each other, provide reliable information, and enable administrators to operate energy supplies across the country, ensuring optimized reliability and efficiency. The smart grid contains sensors that measure and transmit data to adjust the flow of electricity automatically based on supply/demand, and thus, responding to problems becomes quicker and easier. This also plays a crucial role in controlling carbon emissions, by avoiding energy losses during peak load hours and ensuring optimal energy management. The scope of big data analytics in smart grids is huge, as they collect information from raw data and derive intelligent information from the same. However, these benefits of the smart grid are dependent on the active and voluntary participation of the consumers in real-time. Consumers need to be motivated and conscious to avail themselves of the achievable benefits. Incentivizing the appropriate actor is an absolute necessity to encourage prosumers to generate renewable energy sources (RES) and motivate industries to establish plants that support sustainable and green-energy-based processes or products. The current study emphasizes similar aspects and presents a comprehensive survey of the start-of-the-art contributions pertinent to incentive mechanisms in smart grids, which can be used in smart grids to optimize the power distribution during peak times and also reduce carbon emissions. The various technologies, such as game theory, blockchain, and artificial intelligence, used in implementing incentive mechanisms in smart grids are discussed, followed by different incentive projects being implemented across the globe. The lessons learnt, challenges faced in such implementations, and open issues such as data quality, privacy, security, and pricing related to incentive mechanisms in SG are identified to guide the future scope of research in this sector.
... Sharma et al. (2021) studied the integration of CPS, internet of things, cloud computing, and big data to improve agricultural supply chains and boost productivity. Lei et al. (2018) studied the interrelated work on security and reliability in electric power systems. Security issues focus on specific cyber intrusion mechanisms, while reliability issues are more associated with the intrinsic structure and topology of the electric power systems. ...
Industry 4.0 is the fourth industrial revolution for decentralized production through shared facilities to achieve on-demand manufacturing and resource efficiency. It evolves from Industry 3.0 which focuses on routine operation. Data analytics is the set of techniques focus on gain actionable insight to make smart decisions from a massive amount of data. As the performance of routine operation can be improved by smart decisions and smart decisions need the support from routine operation to collect relevant data, there is an increasing amount of research effort in the merge between Industry 4.0 and data analytics. To better understand current research efforts, hot topics, and tending topics on this critical intersection, the basic concepts in Industry 4.0 and data analytics are introduced first. Then the merge between them is decomposed into three components: industry sectors, cyber-physical systems, and analytic methods. Joint research efforts on different intersections with different components are studied and discussed. Finally, a systematic literature review on the interaction between Industry 4.0 and data analytics is conducted to understand the existing research focus and trend.
... This situation changed drastically with Smart Grids: the incorporation of modern IT aspects moved SG more towards cyber-physical systems, which brings tighter constraints related to security and reliability. In modern grids, the cyber part is essential for the proper functioning of the whole power grid, as it processes sensors' data, monitors the grid, handles security, and makes power distribution decisions (Lei et al., 2018). The physical part is thus strongly dependent on the availability of the cyber layer. ...
... ICT schemes have turned into a substantial portion of each facet of our everyday life and its assimilation into the power networks has been increased to suit the growing need in the electric power system [35]. As shown in Figure 2, the implementation of ICT consists of four essential categories for the operations of power system including acquisition, implementation, processing and communication of subsystems [35][36][37][38][39]. • Acquisition: Collects system data such as instantaneous power flow measurements, bus voltages and frequency calculations, the state of circuit breaker, the status of switching tools and then conveys all the data via the communication medium to the processing stage. ...
The integration of improved control techniques with advanced information technologies enables the rapid development of smart grids. The necessity of having an efficient, reliable, and flexible communication infrastructure is achieved by enabling real-time data exchange between numerous intelligent and traditional electrical grid elements. The performance and efficiency of the power grid are enhanced with the incorporation of communication networks, intelligent automation, advanced sensors, and information technologies. Although smart grid technologies bring about valuable economic, social, and environmental benefits, testing the combination of heterogeneous and co-existing Cyber-Physical-Smart Grids (CP-SGs) with conventional technologies presents many challenges. The examination for both hardware and software components of the Smart Grid (SG) system is essential prior to the deployment in real-time systems. This can take place by developing a prototype to mimic the real operational circumstances with adequate configurations and precision. Therefore, it is essential to summarize state-of-the-art technologies of industrial control system testbeds and evaluate new technologies and vulnerabilities with the motivation of stimulating discoveries and designs. In this paper, a comprehensive review of the advancement of CP-SGs with their corresponding testbeds including diverse testing paradigms has been performed. In particular, we broadly discuss CP-SG testbed architectures along with the associated functions and main vulnerabilities. The testbed requirements, constraints, and applications are also discussed. Finally, the trends and future research directions are highlighted and specified.
... The EVCS plan ought to too consider the security and unwavering quality of its cyberphysical framework and its impacts on the framework soundness execution. These factors are forbid [16], [17], and the hazard may increment if such variables and their relationship are disregarded through the EVCS plan and obtainment hones. Chance assessment for control expedite co nsidering the instability in intermittent wind and PV control yield has been examined in [18], [19] to address and measure the taken a toll of anticipated vitality not supplied (EENS) within the framework. ...
This paper presents an assessment of foundation of sun based energized charging station in charge scattering framework. The 9-transport fundamental dispersal structure was used to test the force stream using the Newton Raphson system, contrasting the size and voltage point and the Burrow Quiet program. The 3-transport test structure is used to examine the foundation of the charging station for a sun based electric vehicle in scattering system. The force stream was dissected by choosing the sun based essentialness source and the electric vehicle stack in time plan. The demonstration of sunlight based charge stations and the proportion of electric vehicles are resolved at 100 kWh. The comes to fruition of the control stream test using the Newton Raphson methodology found that the test comes about were in error by contrasting the gauge and voltage point and the Burrow Quiet program that most extraordinary regard of at Transport no. 9 is 2.04% and-3.91%, separately. Though testing the assessment of sun arranged controlled charging station, it is figured out that the charging time will impact the influence mishap of t
... Analysis of cyberattacks is related to the security of the system which is mainly termed cybersecurity. Due to the distinct origination, modelling frameworks and purposes, the impacts of these two factors on the reliability of CPPS are generally analysed independently [11]. Reference [12] gives a review of cybersecurity in the power grid. ...
Due to the greater penetration of renewable energy resources and the increasing complexity of the distribution system, moving towards a smart distribution system is essential and achievable via advanced information and communication technologies. These technologies come with side effects: not only do they change the structure and functionality of the system, their availability and efficiency alter the operation of the system as a whole. The aim of this paper is to examine the reliability of a cyber‐physical microgrid as a part of a smart distribution grid to evaluate the impact of the integration of information and communication technologies into the system and the impact of non‐dispatchable renewable energy resources, that is, photovoltaic and wind farms. This paper proposes a framework for developing reliability assessment tools for a grid‐connected microgrid with a hierarchical three‐level and communication‐based control system. Emphasis is laid on incorporating the interdependencies between the cyber system and the microgrid and on detailed models of renewable energy resources.
... Modern information, computing, and communication technologies together with engineered physical power distribution systems formed a cyber-physical power distribution system. The inter-dependency between the power distribution system and the cyber system makes the distribution system more vulnerable to attacks & threats, and requires the assistance of advanced technologies to ensure the reliability and security of the distribution system [12]. Figure 2 shows the architecture of a smart distribution network. ...
Bi-directional information and energy flow, renewable energy sources, battery energy storage, electric vehicle, self-healing capability, and demand response programs, etc., revolutionized the traditional distribution network into the smart distribution network. Adoption of modern technologies like intelligent meters such as advanced metering infrastructure & Micro-phasor measurement units, data storage, and analysis techniques and incentive-based electricity trading mechanisms can bring this paradigm shift. This study presents an overview of popular technologies that facilitate this transformation, giving focus on some prime technologies such as real-time monitoring based on Micro-phasor measurement units, data storage and analytics, blockchain technology, multi-agent systems, and incentive-based energy trading mechanisms
... In particular, the obtained results can be useful in building new mechanisms for detecting and preventing intrusions in promising Smart Grid systems. One of the promising direction of a further researches can be an argumentation of practical recommendations, other propositions or suggestions concerning a realization of the proposed method and the ways of its use in different techniques of an information security of telecommunications networks and systems [31][32][33][34][35][36][37][38]. ...
The structure and features of the construction for intrusion detection and prevention network systems, as well as methods for the correlation analysis of telecommunication traffic in computer systems and networks are considered. Method for detecting malicious software based on the correlation analysis of network traffic is proposed. In particular, it is shown that using the results of statistical studies of time series on the basis of calculating the difference of correlation integrals (BDS-testing) allows to detect the malicious software traffic to improve the computer networks security of promising Smart Grids systems.
... The EVCS design should also consider the security and reliability of its cyber-physical system and its impacts on the system stability performance. These factors are interdependent [16], [17], and the risk may increase if such factors and their correlation are ignored through the EVCS design and procurement practices. Risk assessment for power dispatch, considering the uncertainty in intermittent wind and PV power output, has been studied in [18] and [19] to address and quantify the cost of expected energy not supplied (EENS) in the system. ...
Several safety regulations particularly concerning the charging electric vehicles (EVs) are developed to ensure the electric safety and prevent the hazardous accidents, in which safety requirements for electric vehicle supply equipment (EVSE) and the EV battery are the two main driving factors. At present, quantitative assessment of electrical safety considering the operation conditions of large-scale electric vehicle charging stations (EVCSs) has still remained a challenge. Driven by the hierarchy of hazard control mechanisms, this paper proposes a holistic approach to evaluate the electrical safety of the large-scale EVCSs when coupled to renewable power generation. Our approach mainly focuses on several topics on the operational safety of EVCS primarily concerning: (1) the facility degradation which could potentially result in a compromised EVSE reliability performance and EVCS protection failure; (2) the cyber-attack challenges when the smart charging and the communication between EVCSs and electric utilities are enabled; (3) the potential mismatch between the renewable output and EVCS demand, which could trigger the system stability challenges during normal operation and inability to supply the critical EV loads during outages. The proposed framework will provide informative guidelines to the EVCS operators for continuous monitoring and effective management of the day-to-day EVCSs operation.
... ISSN: 1693-6930 Authentication techniques in smart grid: a systematic review (Malik Qasaimeh) 1585 SG multicast authentication one-time signature schemes were analyzed by Lei et al. [12], in terms of the parameters of suitability, key management effectiveness, and storage cost. The study found that the optimum theoretical solution was Time-Valid One-Time Signature (TV-OTS), a technique whereby signature-generating and private keys are intermittently refreshed, but more empirical research is necessary to substantiate this solution. ...
... For example, Intrusion Detection and Prevention Systems [39][40][41][42] are also can be built using some elements of artificial intelligence. Critically important information systems in different spheres, including banking, industrial facilities management and Smart Grids are especially interesting for further research [43][44][45][46][47][48][49][50]. ...
The article provides a view on modern technologies, which are used for automatic software vulnerability testing in critically important systems. Features of fuzzing realization (which is based on making many inputs with different mutated data) are also studied. As a result, testing algorithm picks input data that is more likely to cause a fail or incorrect work of software product. Deep learning algorithms are used to decrease the computational complexity of testing process. The use of simple fuzzer and Deep Reinforcement Learning algorithm shows that the amount of mutations necessary to find vulnerabilities decreases by 30%.
Reliability of the smart grids has always been an important factor considered by power system planners. Cyber network failures have significant impacts on the reliability of the smart grids as a cyber-physical system. The complexity of the reliability assessment of cyber-physical systems is significantly higher than traditional power systems due to interdependency between cyber and power network elements. A mapping step is applied to system states to address this interdependency in the reliability assessment task. This paper aims to lower the complexity and computational cost of reliability assessment in cyber-physical systems by proposing a simplified mapping step. The simplification steps are applied to various connection types between cyber components using a defined interconnection matrix based on the cyber network topology. The two-state reliability model probabilities are updated for each cyber element. The proposed method lowers the number of possible system states and computational cost significantly since the effects of some cyber networks are considered in the probability updating step. The proposed approach is applied to different cyber network topologies such as bus, ring, and redundant star in a microgrid. Loss of load probability and expected energy not supplied are calculated as the reliability indices of the system. The results reveal the efficiency of proposed method in reliability assessment of the cyber-physical system using remarkably decreased numbers of system states.
The information technology in a cyber‐physical power system plays a significant role in quickly regulating the energy flow that can cope with the complexity of power system operation and control. The energy processing capability of power systems depends heavily on the reliability of information systems. The reliability model of cyber space includes not only the binary‐state operation‐failure representation of physical devices, but also the multi‐state representation of information flow in corresponding networks. This chapter proposes a reliability modeling and assessment method for the power information system (i.e. cyber space in power system). The proposed composite Markov model would couple physical characteristics and information flow performances in a two‐layer model. The proposed reliability methods combine the sequential Monte‐Carlo simulation with the linear programming model to acquire maximum flows that would supply power demands. The proposed methodology is applied to the reliability analyses of the power information system in the IEEE 14‐bus system in which the performances of the proposed indices are evaluated.
Reliability analysis is one of the major parts in the study of the power system. This paper comprehensively reviews all aspects where reliability analysis plays a vital role including cyber networks, renewable energy sources, and distribution systems. The cyber portion contains the cyber power system model, failures of information and communication networks, various reliability assessment methods, and cost reliability measures. Reliability techniques of hybrid energy sources, uncertainty, and risk evaluation have been explored. It describes the effect of component failure in the distribution system, sensitivity analysis, and methodology for reliability. Lastly, it delivers a brief description of the microgrid, its challenges, and its reliability. This review paper is expected to provide reliability enhancement strategies and their benefits in summary to upgrade the infrastructure of our modern power systems.KeywordsPower system reliabilitySmart gridICT networkCyber securityRenewable resourcesCPPS modelDistribution systems
Industry 4.0 (I-4.0) is referred to as ‘fourth industrial revolution’ towards incorporation of artificial intelligence and digitalization of industrial systems. It is meticulously associated with the development and advancement of evolving technologies such as: Internet of Things, Cyber-Physical System, Information and Communications Technology, Enterprise Architecture, and Enterprise Integration. Power systems of today face several challenges that need to be addressed and application of these technologies can make the modern power systems become more effective, reliable, secure, and cost-effective. Therefore, a widespread analysis of I- 4.0 is performed in this paper and a summary of the outcomes, future scope, and real-world application of I- 4.0 on the electrical utility industry (EUI) is reported by reviewing the existing literature. This report will be helpful to the investigators interested in the area of I- 4.0 and for application in EUI.
In this paper, various cyber-physical system techniques are proposed to control and monitor the smart grid. Due to the increased dependency on IT and automated components of the electrical power system as in case of smart grid, the vulnerability of cyber security has increased, and thus, it leads to the importance of cyber security. Thus, cyber-physical energy systems such as smart grid can get influenced by cyber-attacks and cause unintentional tripping leading to the undesired power outage. Hence, the attacker types, attack types, their impact on the whole smart grid and its repercussions become significant so that they can be eliminated timely, and this is where the monitoring and controlling of smart grid by cyber security system become helpful. The potential attacks inject malicious control signals, and thus, it changes the normal operation of digital relays and circuit breakers causing relays to trip at an undesired time when it need not to trip, which in turn results in spurious tripping, when there is no fault in the system. However, detecting and discriminating anomalies or problems caused by the cyber-attack against the power system are yet to be satisfactorily achieved.
This paper proposes a probabilistic extension to flexible hybrid state estimation (FHSE) for cyber-physical systems (CPSs). The main goal of the algorithm is improvement of the system state tracking when realistic communications are taken into account, by optimizing information and communication technology (ICT) usage. These advancements result in: 1) coping with ICT outages and inevitable irregularities (delay, packet drop and bad measurements); 2) determining the optimized state estimation execution frequencies based on expected measurement refresh times. Additionally, information about CPSs is gathered from both the phasor measurement units (PMU) and SCADA-based measurements. This measurement transfer introduces two network observability types, which split the system into observable (White) and unobservable (Grey) areas, based on 1) deployed measuring instruments (MIs) and 2) received measurements. A two-step bad data detection (BDD) method is introduced for ICT irregularities and outages. The proposed algorithm benefits are shown on two IEEE test cases with time-varying load/generation: 14-bus and 300-bus.
The information technology in a cyber-physical power system plays a significant role in quickly regulating the energy flow that can cope with the complexity of power system operation and control. The energy processing capability of power systems depends heavily on the reliability of information systems. The reliability model of cyber space includes not only the binary-state operation-failure representation of physical devices, but also the multi-state representation of information flow in corresponding networks. This paper proposes a reliability modeling and assessment method for the power information system (i.e., cyber space in power system). The proposed composite Markov model would couple physical characteristics and information flow performances in a two-layer model. The proposed reliability methods combine the sequential Monte-Carlo simulation with the linear programming model to acquire maximum flows that would supply power demands. The proposed methodology is applied to the reliability analyses of the power information system in the IEEE 14-bus system in which the performances of the proposed indices are evaluated.
This paper introduces an analytical method, based on the Complex Network Theory (CNT), to assess the risk of the Smart Grid failure due to communication network malfunction, associated with latency and ICT network reliability. Firstly, the communication architecture is modelled using a two-step CNT framework-an Operation Graph (OG) in step one and a Reliability Graph (RG) in step two. Secondly, the latency of data packets and the reliability of each communication device are incorporated into the model to identify the reliability of all operational communication paths for successful power system control purposes. Then, the risk of Smart Grid failure due to the communication network malfunction is quantified using a System Reliability Index (SRI). Next, sensitivity analysis is performed to assess the importance of each communication network component using two innovative Importance Measures (IM), namely System Reliability Advancement Worth (SRAW) and System Reliability Deterioration Worth (SRDW). Finally, the proposed approach is demonstrated on a laboratory-scale communication network.
The evolution of architecture of contemporary SCADA systems follows trends in industry sector. Today, SCADA systems imply the application of smart grid and artificial intelligence concepts, the use of IP-based technologies, new mobile devices, as well as the use of private and public cloud computing services. Security risk assessment of contemporary SCADA systems needs to include new security aspects. This chapter analyzes information security in contemporary SCADA systems. Focus is then directed to SCADA network architecture and recommended security mechanisms for mitigating the security risk that assumes the use of Defense in Depth concept. Special attention is paid to SCADA-specific intrusion detection and intrusion prevention technologies. A case study outlines recommendations for security risk mitigation of SCADA system in a hydropower plant.
Cyber-Physical Systems (CPSs) combine computational and physical components enabling real-world interaction. Digitization, decentralization, and high connectivity, as well as incorporation of various enabling technologies, raise various security issues. These security concerns may affect safety, endangering assets and even human lives. This is especially true for CPS utilization in different sectors of great significance, including manufacturing or critical infrastructures, creating a need for efficiently handling relevant security issues. Including security as part of a software-intensive technical system (i.e., the CPS) that can be distributed and highly resilient highlights the need for appropriate security methodologies to be applied on the CPS from the engineering stage during CPS design. The efficient security-related processes that are implemented at design time have an impact on security monitoring during the CPS operational phase (at run-time). Efficient and accurate security monitoring that follows security-by-design principles can be a potent tool in the hands of the CPS manager for detecting and mitigating cyber threats. Monitoring traffic and activity at the system boundaries, detecting changes to device status and configuration, detecting suspicious activity indicating attacks, detecting unauthorized activity that is suspicious or violates security policies, and timely responding to security incidents and recovering from them are issues that need to be efficiently tackled with by security monitoring. In this chapter, we explore the various CPS cybersecurity threats and discuss how adding security as a parameter at the CPS design phase can provide a well-structured and efficient approach on providing strong security CPS foundations. New technologies on CPS security design are presented and emerging security directions are discussed. Furthermore, in the chapter, the different aspects of security monitoring are presented with a special emphasis on CPSs, discussing the various existing monitoring approaches that are followed in order to detect security issues at run-time. Specific use cases of CPSs in the manufacturing domain and with reference to critical infrastructures are also detailed and security requirements like confidentiality, integrity, and availability are discussed.
Electrical power system developed few decades back is now being transformed into smart grid power systems due to the availability of many utilities like Smart metering system with auto monitoring quality of power, automatic control by Supervisory Control and Data Acquisition (SCADA) system, and usage of renewable or green energy sources for reduction of carbon footprint. Smart grid provides a solution for stability, reliability, efficiency, voltage regulation, cost, air pollution, and safety of energy systems. The smart grid system is designed for visualizing and monitoring of real-time demand of power and distribution of electricity as per load from consumers. Smart grid infrastructure system is a fusion of two infrastructures, i.e., physical and cyber infrastructure. It makes use of both the physical and digital infrastructure. Cyber infrastructure makes use of a communication network and SCADA system for control and trustworthy data communication in two way communication mode.
An increasing interest is emerging on the development of smart grid cyber-physical system testbeds. As new communication and information technologies emerge, innovative cyber-physical system testbeds need to leverage realistic and scalable platforms. Indeed, the interdisciplinary structure of the smart grid concept compels heterogeneous testbeds with different capabilities. There is a significant need to evaluate new concepts and vulnerabilities as opposed to counting on solely simulation studies especially using hardware-in-the-loop test platforms. In this paper, we present a comprehensive survey on cyber-physical smart grid testbeds aiming to provide a taxonomy and insightful guidelines for the development as well as to identify the key features and design decisions while developing future smart grid testbeds. First, this survey provides a four step taxonomy based on smart grid domains, research goals, test platforms, and communication infrastructure. Then, we introduce an overview with a detailed discussion and an evaluation on existing testbeds from the literature. Finally, we conclude the paper with a look on future trends and developments in cyber-physical smart grid testbed research.
A communication infrastructure is an essential part to the success of the emerging smart grid. A scalable and pervasive communication infrastructure is crucial in both construction and operation of a smart grid. In this paper, we present the background and motivation of communication infrastructures in smart grid systems. We also summarize major requirements that smart grid communications must meet. From the experience of several industrial trials on smart grid with communication infrastructures, we expect that the traditional carbon fuel based power plants can cooperate with emerging distributed renewable energy such as wind, solar, etc, to reduce the carbon fuel consumption and consequent green house gas such as carbon dioxide emission. The consumers can minimize their expense on energy by adjusting their intelligent home appliance operations to avoid the peak hours and utilize the renewable energy instead. We further explore the challenges for a communication infrastructure as the part of a complex smart grid system. Since a smart grid system might have over millions of consumers and devices, the demand of its reliability and security is extremely critical. Through a communication infrastructure, a smart grid can improve power reliability and quality to eliminate electricity blackout. Security is a challenging issue since the on-going smart grid systems facing increasing vulnerabilities as more and more automation, remote monitoring/controlling and supervision entities are interconnected.
Smart grid initiatives are becoming more and more achievable through the use of information infrastructures that feature peer-to-peer communication, monitoring, protection and automated control. The analysis of smart grid operation requires considering the reliability of the cyber network as it is neither invulnerable nor failure free. This paper quantitatively evaluates the reliability of modern power systems, which incorporates the impact of cyber network failures on the reliability of the power network. In this paper, four types of interdependencies are defined and a new concept of state mapping is proposed to map the failures in the cyber network to the failures of the power network. Furthermore, in order to evaluate the impact of direct cyber-power interdependencies on the reliability indices, two optimization models are introduced to maximize the data connection in the cyber network and minimize the load shedding in the power network. The effectiveness of proposed reliability evaluation method is shown by a smart microgrid application. The methodology presented in this paper is a start point to optimize the future power grid which has increasingly interdependencies between cyber and power networks.
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.
Cyber security is becoming a major concern of smart grids, as the functionality of a smart grid is highly dependent on the cyber communication. Therefore, it is important to study the impact of cyber attacks on smart grids. This paper discusses several types of cyber attacks. Then, it presents results of studies of impacts on transient angle and transient voltage stability due to cyber attacks on two voltage support devices, SVC and STATCOM, in an 8-bus test system. The 8 bus system and voltage devices are simulated and the stability analysis is performed with DSATools™. The results showed that some modification cyber attacks can make the system angle or voltage unstable, following a physical fault in the system.
Vulnerability assessment is a requirement of NERC's cybersecurity standards for electric power systems. The purpose is to study the impact of a cyber attack on supervisory control and data acquisition (SCADA) systems. Compliance of the requirement to meet the standard has become increasingly challenging as the system becomes more dispersed in wide areas. Interdependencies between computer communication system and the physical infrastructure also become more complex as information technologies are further integrated into devices and networks. This paper proposes a vulnerability assessment framework to systematically evaluate the vulnerabilities of SCADA systems at three levels: system , scenarios , and access points . The proposed method is based on cyber systems embedded with the firewall and password models, the primary mode of protection in the power industry today. The impact of a potential electronic intrusion is evaluated by its potential loss of load in the power system. This capability is enabled by integration of a logic-based simulation method and a module for the power flow computation. The IEEE 30-bus system is used to evaluate the impact of attacks launched from outside or from within the substation networks. Countermeasures are identified for improvement of the cybersecurity.
In this paper, we analyze the cyber security of state estimators in Supervisory Control and Data Acquisition (SCADA) systems operating in power grids. Safe and reliable operation of these critical infrastructure systems is a major concern in our society. In current state estimation algorithms there are bad data detection (BDD) schemes to detect random outliers in the measurement data. Such schemes are based on high measurement redundancy. Although such methods may detect a set of very basic cyber attacks, they may fail in the presence of a more intelligent attacker. We explore the latter by considering scenarios where deception attacks are performed, sending false information to the control center. Similar attacks have been studied before for linear state estimators, assuming the attacker has perfect model knowledge. Here we instead assume the attacker only possesses a perturbed model. Such a model may correspond to a partial model of the true system, or even an out-dated model. We characterize the attacker by a set of objectives, and propose policies to synthesize stealthy deceptions attacks, both in the case of linear and nonlinear estimators. We show that the more accurate model the attacker has access to, the larger deception attack he can perform undetected. Specifically, we quantify trade-offs between model accuracy and possible attack impact for different BDD schemes. The developed tools can be used to further strengthen and protect the critical state-estimation component in SCADA systems.
Introduction. Generating Capacity-Basic Probability Methods. Generating Capacity-Frequency and Duration Method. Interconnected Systems. Operating Reserve. Composite Generation and Transmission Systems. Distribution Systems-Basic Techniques and Radial Networks. Distribution Systems-Parallel and Meshed Networks. Distribution Systems-Extended Techniques. Substations and Switching Stations. Plant and Station Availability. Applications of Monte Carlo Simulation. Evaluation of Reliability Worth. Epilogue. Appendix 1: Definitions. Appendix 2: Analysis of the IEEE Reliability Test System. Appendix 3: Thirdorder Equations for Overlapping Events. Solutions to Problems. Index.
Reliability test systems are used as a benchmark tool to test and validate probabilistic methods developed for power systems reliability evaluation. The IEEE Reliability Test System (RTS) and the Roy Billinton Test System (RBTS) are the two most widely used test systems for studying new ideas of power system reliability analysis. With the increasing penetration of Information and Communication Technologies (ICTs), modern power system performance is becoming increasingly dependent on cyber infrastructure. To facilitate the development of methods to quantitatively evaluate the impact of cyber failures on power system reliability, it is necessary to develop a reliability test system that incorporates ICT features. This paper proposes the idea of developing a cyber-physical reliability test system. A portion of the IEEE RTS is extended with ICT configurations as an example to illustrate this idea. Technical considerations and challenges in developing a large cyber-physical reliability test system are also discussed with feasible solutions suggested. The purpose of this paper is to propose initial thoughts of developing a benchmark test system for electric power grid cyber-physical reliability studies, based on which a full-fledged system can be established later with cumulative efforts and inputs from both academia and industry.
One of the main drawbacks of the existing wide-area damping controller (WADC) that are usually tuned based on several selected typical operating conditions, is its limited adaptability to continuous variations in operating conditions. An adaptive WADC employing the lead-lag structure using measurement-driven model is proposed in this paper. The state subspace model is identified online using ambient data or ring-down data to represent system oscillatory behaviors. The parameters of the lead-lag time constants can be updated based on the new residue derived from the identified model, while the new control gain can also be determined based on the identified model to achieve maximum damping ratio. Moreover, a delay compensator adopting the lead-lag structure and the quadratic interpolation algorithm are utilized to handle random time delay and data packet loss, respectively. The effectiveness of the proposed adaptive WADC is validated by the case study in the two-area four-machine system.
Cyber-induced dependent failures are important to be considered in composite system reliability evaluation. Because of the complexity and dimensionality, Monte Carlo simulation is a preferred method for composite system reliability evaluation. The non-sequential Monte Carlo or sampling generally requires less computational and storage resources than sequential techniques and is generally preferred for large systems where components are independent or only a limited dependency exists. However, cyber-induced events involve dependent failures, making it difficult to use sampling methods. The difficulties of using sampling with dependent failures are discussed and a solution is proposed. The basic idea is to generate a representative state space from which states can be sampled. The probabilities of representative state space provide an approximation of the joint distribution and are generated by a sequential simulation in this paper but it may be possible to find alternative means of achieving this objective. The proposed method preserves the dependent features of cyber-induced events and also improves the efficiency. Although motivated by cyber-induced failures, the technique can be used for other types of dependent failures as well. A comparative study between a purely sequential methodology and the proposed method is presented on an extended Roy Billinton Test System.
With the increasing deployment of smart grid technologies, modern electric power systems are becoming more and more dependent on their cyber infrastructure. The unavailability of communication networks inevitably influences the reliability of power systems. Therefore, it is very important to study the malfunctions of cyber networks and their impact on power system reliability. In this paper, to illustrate the ideas, a 4-bus power system is extended to include the Ethernet-based protection system at each bus. The failure modes and impact of each individual component are analyzed. The effects of link failures resulting from packet delay are also considered. The term "link failure" in this paper refers to an event in which a link temporarily or permanently fails to transmit information in a timely manner. The example presents an effective approach to evaluate integrated cyber-physical power systems and provides possible enhancement suggestions for future research.
In this paper, we analyze control-related attacks in SCADA (supervisory control and data acquisition) systems for power grids. This class of attacks introduces a serious threat to power systems, because attackers can directly change the system's physical configuration using malicious control commands crafted in a legitimate format. To detect such attacks, we propose a semantic analysis framework that integrates network intrusion detection systems (IDSes) with a power flow analysis capable of estimating the execution consequences of control commands. To balance detection accuracy and latency, the parameters of the power flow analysis algorithm are dynamically adapted according to real-time system dynamics. Our experiments on IEEE 24-bus, 30-bus, and 39-bus systems and a 2736-bus system demonstrate that (1) by opening 3 transmission lines, an attacker can put the tested system into an insecure state, and (2) the semantic analysis can complete detection in 200 milliseconds for the large-scale 2736-bus system with about 0.78% false positives and 0.01% false negatives, which allow for timely responses to intrusions.
Protection system failures have been recognized as major causes of expanded outages and thereby affect bulk power system reliability. With the rapid progress of smart grid technologies, legacy protection systems with hardwired architecture are being gradually replaced by computer and communication networks consisting of multi-functional and smart Intelligent Electronic Devices (IEDs). In this paper, a systematic methodology for considering the effect of cyber-malfunctions in substations on power system reliability is proposed by extending the concepts we previously presented. The Roy Billinton Test System (RBTS) is extended to include substation protection systems with modern architecture, which is an important step as a test system like this is currently unavailable. The proposed approach is then demonstrated on this test system. The quantitative relationship between switching time and system-wide energy unavailability is studied. The results of our study clearly indicate the impact of protection system failures on system-wide reliability indices and signify the importance of accelerating line switching process. Furthermore, the overall methodology used in this paper provides a tractable and scalable option for the reliability evaluation of large cyber-physical power systems.
This paper proposes a novel reliability modeling and analysis methodology for modern substation protection systems. A typical IEC 61850 based substation protection system is designed and analyzed using this methodology as an example. This system includes cyber components such as Merging Units (MUs), Intelligent Electronic Devices (IEDs), and process bus, as well as physical components such as transformers, circuit breakers, and transmission lines. A general technique for cyber-physical system reliability analysis and the concept of cyber-physical interface matrix are presented. The failure modes of individual components and their impacts on the overall system are modeled and numerically analyzed. The utility of the cyber-physical interface matrix in the reliability analysis of a composite power system is also illustrated. The cyber-physical interface matrix is the critical idea that helps making the analysis tractable. The results of our study provide important and precise information for substation reliability evaluation and pave the way for the reliability analysis of complex and large scale cyber-physical systems.
The development of a smarter electric grid will depend on increased deployments of information and communication technology (ICT) to support novel communication and control functions. Unfortunately, this additional dependency also expands the risk from cyber attacks. Designing systems with adequate cyber security depends heavily on the availability of representative environments, such as testbeds, where current issues and future ideas can be evaluated. This paper provides an overview of a smart grid security testbed, including the set of control, communication, and physical system components required to provide an accurate cyber-physical environment. It then identifies various testbed research applications and also identifies how various components support these applications. The PowerCyber testbed at Iowa State University is then introduced, including the architecture, applications, and novel capabilities, such as virtualization, Real Time Digital Simulators (RTDS), and ISEAGE WAN emulation. Finally, several attack scenarios are evaluated using the testbed to explore cyber-physical impacts. In particular, availability and integrity attacks are demonstrated with both isolated and coordinated approaches, these attacks are then evaluated based on the physical system's voltage and rotor angle stability.
A cyber-power system, a type of cyber-physical system, contains two interconnected infrastructures: a power network and a cyber network. The cyber network monitors, protects and controls the power network. Without the cyber network, the power network cannot operate efficiently or reliably. This paper studies the cyber-power interdependencies in smart grids and categorizes four types of interdependencies between cyber and power networks. The proposed classification permits the assessment of adverse effects of cyber network failures on the power network's operation. Two applications of cyber-power systems, automated substations and micro grids, are discussed in this paper, and certain cyber-power interdependencies are listed as examples.
Malicious attacks against power systems are investigated, in which an adversary controls a set of meters and is able to alter the measurements from those meters. Two regimes of attacks are considered. The strong attack regime is where the adversary attacks a sufficient number of meters so that the network state becomes unobservable by the control center. For attacks in this regime, the smallest set of attacked meters capable of causing network unobservability is characterized using a graph theoretic approach. By casting the problem as one of minimizing a supermodular graph functional, the problem of identifying the smallest set of vulnerable meters is shown to have polynomial complexity. For the weak attack regime where the adversary controls only a small number of meters, the problem is examined from a decision theoretic perspective for both the control center and the adversary. For the control center, a generalized likelihood ratio detector is proposed that incorporates historical data. For the adversary, the trade-off between maximizing estimation error at the control center and minimizing detection probability of the launched attack is examined. An optimal attack based on minimum energy leakage is proposed.
There is significant interest to develop proactive approaches to cyber defense, in which future attack strategies are anticipated and these insights are incorporated into defense designs. This paper considers the problem of protecting computer networks against intrusions and other attacks, and leverages the coevolutionary relationship between attackers and defenders to derive two new methods for proactive network defense. The first method is a bipartite graph-based machine learning algorithm which enables information concerning previous attacks to be “transferred” for application against novel attacks, thereby substantially increasing the rate with which defense systems can successfully respond to new attacks. The second approach involves exploiting basic threat information (e.g., from cyber security analysts) to generate “synthetic” attack data for use in training defense systems, resulting in networks defenses that are effective against both current and (near) future attacks. The utility of the proposed methods is demonstrated by showing that they outperform standard techniques for the task of detecting malicious network activity in two publicly-available cyber datasets.
This paper presents a framework for cyber attack impact analysis of a smart grid. We focus on the model synthesis stage in which both cyber and physical grid entity relationships are modeled as directed graphs. Each node of the graph has associated state information that is governed by dynamical system equations that model the physics of the interaction (for electrical grid components) or functionality (for cyber grid elements). We illustrate how cause-effect relationships can be conveniently expressed for both analysis and extension to large-scale smart grid systems.
Modern power grids with their physical current-carrying components and the embedded computer, communication and control networks are fast emerging as one of the largest and most complex cyber-physical systems. The addition of more sensing, communication, variable power sources and storage under the renewable energy thrust and smart grid initiative will add even higher orders of dimensionality and complexity. This order of complexity, intended to achieve higher levels of efficiency, flexibility and fault tolerance, can also be a source of more failures of complex nature that can actually degrade reliability. Yet, almost the entire literature on power system reliability evaluation is concerned only with the failures of the current-carrying part of the power grid. The literature on the reliability of power systems examining the overlaid cyber components is scant and that of their mutual interdependence is almost non-existent. The objective of this paper is to explore the topic of the reliability assurance of cyber-physical systems and possibly stimulate more research in this area.
We study the economic impact of a potential class of integrity cyber attacks, named false data injection attacks, on elec- tric power market operations. In particular, we show that with the knowledge of the transmission system topology, attackers may cir- cumvent the bad data detection algorithms equipped in today's state estimator. This, in turn, may be leveraged by attackers for consistent financial arbitrage such as virtual bidding at selected pairs of nodes. This paper is a first attempt to formalize the eco- nomic impact of malicious data attacks on real-time market opera- tions. We show how an attack could systematically construct a prof- itable attacking strategy, in the meantime being undetected by the system operator. Such a result is also valuable for the system oper- ators to examine the potential economic loss due to such cyber at- tack. The potential impact of the false data injection attacks is illus- trated on real-time market operations of the IEEE 14-bus system.
Cybersecurity of the substations in a power system is a major issue as the substations become increasingly dependent on computer and communication networks. This paper is concerned with anomaly detection in the computer network environment of a substation. An anomaly inference algorithm is proposed for early detection of cyber-intrusions at the substations. The potential sce- nario of simultaneous intrusions launched over multiple substa- tions is considered. The proposed detection method considers tem- poral anomalies. Potential intrusion events are ranked based on the credibility impact on the power system. Snapshots of anomaly entities at substations are described. Simulation results using the modified IEEE 118-bus system have shown the effectiveness of the proposed method for systematic identification. The result of this research is a tool to detect cyber-intrusions that are likely to cause significant damages to the power grid.
The development of a trustworthy smart grid requires a deeper understanding of potential impacts resulting from successful cyber attacks. Estimating feasible attack impact requires an evaluation of the grid's dependency on its cyber infrastructure and its ability to tolerate potential failures. A further exploration of the cyber–physical relationships within the smart grid and a specific review of possible attack vectors is necessary to determine the adequacy of cybersecurity efforts. This paper highlights the significance of cyber infrastructure security in conjunction with power application security to prevent, mitigate, and tolerate cyber attacks. A layered approach is introduced to evaluating risk based on the security of both the physical power applications and the supporting cyber infrastructure. A classification is presented to highlight dependencies between the cyber–physical controls required to support the smart grid and the communication and computations that must be protected from cyber attack. The paper then presents current research efforts aimed at enhancing the smart grid's application and infrastructure security. Finally, current challenges are identified to facilitate future research efforts.
This book covers a wide range of relevant material related to present-day knowledge and application in power system reliability. Increasing socioeconomic pressures to create safe and reliable power systems are being exerted on utilities by government, environmental groups and society in general. The material presented in this book will play a role in finding acceptable solutions to such pressures and will encourage the increased use of reliability techniques in practical applications.
The IEEE Reliability Test System (RTS) developed by the
Application of Probability Method Subcommittee has been used to compare
and test a wide range of generating capacity and composite system
evaluation techniques and subsequent digital computer programs. A basic
reliability test system is presented which has evolved from the
reliability education and research programs conducted by the Power
System Research Group at the University of Saskatchewan. The basic
system data necessary for adequacy evaluation at the generation and
composite generation and transmission system levels are presented
together with the fundamental data required to conduct
reliability-cost/reliability-worth evaluation
IEEE tutorial on electric delivery system reliability evaluation
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Meliopoulos, and C. Singh, "IEEE tutorial on electric delivery system
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Cyber-physical systems security for smart grid
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security for smart grid," in Power Systems Engineering Research Center
(PSERC) -Future Grid Initiative White Paper, 2012.
IEC TC57 WG15: IEC 62351 Security Standards for the Power System Information Infrastructure
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