Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> There is virtually universal agreement that it is necessary to upgrade the electric grid to increase overall system efficiency and reliability. Much of the technology currently in use by the grid is outdated and in many cases unreliable. There have been three major blackouts in the past ten years. The reliance on old technology leads to inefficient systems, costing unnecessary money to the utilities, consumers, and taxpayers. To upgrade the grid, and to operate an improved grid, will require significant dependence on distributed intelligence and broadband communication capabilities. The access and communications capabilities require the latest in proven security technology for extremely large, wide-area communications networks. This paper discusses key security technologies for a smart grid system, including public key infrastructures and trusted computing. <s> BIB001 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> The smart grid moves new power grid automation systems from being proprietary and closed to the current state of information technology (IT) which is highly interconnected and open. But open and interconnected automation platforms bring about major security challenges. The power grid automation network has inherent security risks due to the fact that the systems and applications for the power grid were originally designed without much consideration of cybersecurity. This paper first introduces scope and functionalities of power grid, its automation and control system, and communications. Potential cyberattacks and their adverse impacts on power grid operation are discussed, a general SCADA cyberattack process is presented. This paper discusses the major challenges and strategies to protect smart grid against cyberattacks and finally proposes a conceptual layered framework for protecting power grid automation systems against cyberattacks without compromising timely availability of control and signal data. The proposed “bump-in-the-wire” approach also provides security protection for legacy systems which do not have enough computational power or memory space to perform security functionalities. The on-site system test of the developed prototype security system is briefly presented as well. <s> BIB002 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> This paper systematically investigates the novel idea of applying the next generation wireless technology, cognitive radio network, for the smart grid. In particular, system architecture, algorithms, and hardware testbed are studied. A microgrid testbed supporting both power flow and information flow is also proposed. Control strategies and security considerations are discussed. Furthermore, the concept of independent component analysis (ICA) in combination with the robust principal component analysis (PCA) technique is employed to recover data from the simultaneous smart meter wireless transmissions in the presence of strong wideband interference. The performance illustrates the gain of bringing the state of the art mathematics to smart grid. <s> BIB003 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> Supervisory Control and Data Acquisition (SCADA) systems control and monitor industrial and critical infrastructure functions, such as electricity, gas, water, waste, railway, and traffic. Recent attacks on SCADA systems highlight the need of stronger SCADA security. It is important to analyze the security risks and develop appropriate security solutions to protect such systems. However, a key problem is the lack of proper modeling tools to evaluate the security of SCADA systems. As widely accepted in academic and industrial communities, it is impractical to conduct security experiments on live systems. A modeling simulation tool would enable the simulation of SCADA systems with the benefit of testing different attack and security solutions. This paper proposes a simulation tool for building SCADA simulations that supports the integration of external devices and applications. A key benefit of this tool is the ability to test the effect of attacks on real devices and applications, even though using a simulated environment. The paper further describes two case studies that demonstrate how the tool can be efficiently used to create SCADA simulations and perform malicious attacks. <s> BIB004 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> The critical infrastructures of our society are in the process of being modernized. Most significantly impacted are the industrial control systems through replacement of old electromechanical systems with advanced computing and communication technologies. This modernization has introduced new vulnerabilities to those infrastructures. Securing critical infrastructures is a challenging research problem, as these control systems were not designed with security in mind. This paper presents a testbed designed to study and simulate the various available techniques for securing and protecting Supervisory Control and Data Acquisition (SCADA) systems against a wide range of cyber attacks. The testbed is also used to evaluate the detection rate, false alerts and effectiveness of the protection techniques. We present preliminary results on using the testbed to detect a selected set of cyber attacks and the impact of the protection techniques on the operations of the system. <s> BIB005 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> The smart grid's heavy reliance on cyber resources introduces numerous security concerns. The substantial attack surface presented by the advanced metering infrastructure (AMI) along with the dissemination of sensitive data including privacy, billing, and control information will provide attackers with significant economic incentive. In addition, the scale and complexity of the architecture will stress the capabilities of many security controls such as public key encryption (PKI), authentication, and access control. The aforementioned concerns produce a requirement for increased risk management including security models that have the capability to scale to such a complex environment. A security model is introduced to represent various privilege states in a large architecture and evaluates viable paths that an attacker could exploit. The resulting model is used to produce a quantitative information-based exposure metric to evaluate the completeness of implemented security mechanisms. Various applications are proposed to show how the metric can enhance current risk management processes by identifying information dependencies of the deployed security mechanisms. Finally, the applicability of the proposed methodologies has been evaluated through a simulation study using realistic AMI infrastructure to demonstrate the utility of the proposed metric. <s> BIB006 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> Data injection attacks to manipulate system state estimators on power grids are considered. A unified formulation for the problem of constructing attacking vectors is developed for linearized measurement models. Based on this formulation, a new low-complexity attacking strategy is shown to significantly outperform naive l1 relaxation. It is demonstrated that it is possible to defend against malicious data injection if a small subset of measurements can be made immune to the attacks. However, selecting such subsets is a high-complexity combinatorial problem given the typically large size of electrical grids. To address the complexity issue, a fast greedy algorithm to select a subset of measurements to be protected is proposed. Another greedy algorithm that facilitates the placement of secure phasor measurement units (PMUs) to defend against data injection attacks is also developed. Simulations on the IEEE test systems demonstrate the benefits of the proposed algorithms. <s> BIB007 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> State estimation is a key element in today's power systems for reliable system operation and control. State estimation collects information from a large number of meter measurements and analyzes it in a centralized manner at the control center. Existing state estimation approaches were traditionally assumed to be able to tolerate and detect random bad measurements. They were, however, recently shown to be vulnerable to intentional false data injection attacks. This paper fully develops the concept of load redistribution (LR) attacks, a special type of false data injection attacks, and analyzes their damage to power system operation in different time steps with different attacking resource limitations. Based on damaging effect analysis, we differentiate two attacking goals from the adversary's perspective, i.e., immediate attacking goal and delayed attacking goal. For the immediate attacking goal, this paper identifies the most damaging LR attack through a max-min attacker-defender model. Then, the criterion of determining effective protection strategies is explained. The effectiveness of the proposed model is tested on a 14-bus system. To the author's best knowledge, this is the first work of its kind, which quantitatively analyzes the damage of the false data injection attacks to power system operation and security. Our analysis hence provides an in-depth insight on effective attack prevention with limited protection resource budget. <s> BIB008 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> A smart grid is a new form of electricity network with high fidelity power-flow control, self-healing, and energy reliability and energy security using digital communications and control technology. To upgrade an existing power grid into a smart grid, it requires significant dependence on intelligent and secure communication infrastructures. It requires security frameworks for distributed communications, pervasive computing and sensing technologies in smart grid. However, as many of the communication technologies currently recommended to use by a smart grid is vulnerable in cyber security, it could lead to unreliable system operations, causing unnecessary expenditure, even consequential disaster to both utilities and consumers. In this paper, we summarize the cyber security requirements and the possible vulnerabilities in smart grid communications and survey the current solutions on cyber security for smart grid communications. <s> BIB009 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> Cyber security is becoming an area of growing concern in the electric power industry with the development of smart grid. False data injection attack, which is against state estimation through SCADA network, has recently attracted wide research interests. This paper further develops the concept of load redistribution (LR) attack, a special type of false data injection attack. The damage of LR attacks to power system operations can manifest in an immediate or a delayed fashion. For the immediate attacking goal, we show in this paper that the most damaging attack can be identified through a max-min attacker-defender model. Benders decomposition within a restart framework is used to solve the bilevel immediate LR attack problem with a moderate computational effort. Its effectiveness has been validated by the Karush-Kuhn-Tucker (KKT)-based method solution in our previous work. For the delayed attacking goal, we propose a trilevel model to identify the most damaging attack and transform the model into an equivalent single-level mixed-integer problem for final solution. In summary, this paper enables quantitative analysis of the damage of LR attacks to power system operations and security, and hence provides an in-depth insight on effective attack prevention when resource budgets are limited. A 14-bus system is used to test the correctness of the proposed model and algorithm. <s> BIB010 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> To secure the network communication for the smart grid, it is important that a secure key management scheme is needed. The focus of this paper is on the secure key distribution for the smart grid. In this paper, we first overview the key management scheme recently proposed by Wu-Zhou and show it is vulnerable to the man-in-the-middle attack. Then we propose a new key distribution protocol and demonstrate it is secure and efficient for smart grid network. Applying traditional PKI to the smart grid requires significant work and maintenance of the public key. By using Kerberos to smart grid may lose authentication from the third party due to power outages. Therefore, we propose a scheme for a smart grid using a trusted third party which not only has no issue on key revocation, but also the third party can be easily duplicated in case power outages occur. <s> BIB011 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> The necessity to promote smart grid (SG) has been recognized with a strong consensus. The SG integrates electrical grids and communication infrastructures and forms an intelligent electricity network working with all connected components to deliver sustainable electricity supplies. Many advanced communication technologies have been identified for SG applications with a potential to significantly enhance the overall efficiency of power grids. In this paper, the challenges and applications of communication technologies in SG are discussed. In particular, we identify three major challenges to implement SG communication systems, including standards interoperability, cognitive access to unlicensed radio spectra, and cyber security. The issues to implement SG communications on an evolutional path and its future trends are also addressed. The aim of this paper is to offer a comprehensive review of state-of-the-art researches on SG communications. <s> BIB012 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> 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. <s> BIB013 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> Key management for secure communications of Advanced Metering Infrastructure is an unsolved problem until now. The difficulties and their basic solutions for AMI to choose a key management scheme will be summed up after the studies of AMI system structure, business process and cyber security requirements, proposing a key management scheme based on a hybrid-tree graph for AMI. The cyber security, including key security, key freshness, forward & backward security, etc., can be satisfied by the presented scheme, while the overhead of the scheme is reasonable. Based on the analysis, the presented scheme is a possible solution for AMI. <s> BIB014 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> Malicious data attacks on specific buses of the power grid can lead to incorrect state estimation and in turn affect electricity prices and operational stability. A hidden data attack model is presented in this paper which involves an adversary corrupting meter readings in the grid to produce undetectable errors in a set of critical state variables. A polynomial time algorithm is given to identify the minimum set of measurements needed by the adversary to corrupt the desired state variables. To prevent such hidden attacks, a greedy protection algorithm is proposed for two cases, one where the adversary is resource limited and the other where the adversary has no resource constraint. The performances of the proposed algorithms are demonstrated through simulations on different IEEE test systems. <s> BIB015 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> The normal operation of power system relies on accurate state estimation that faithfully reflects the physical aspects of the electrical power grids. However, recent research shows that carefully synthesized false-data injection attacks can bypass the security system and introduce arbitrary errors to state estimates. In this paper, we use graphical methods to study defending mechanisms against false-data injection attacks on power system state estimation. By securing carefully selected meter measurements, no false data injection attack can be launched to compromise any set of state variables. We characterize the optimal protection problem, which protects the state variables with minimum number of measurements, as a variant Steiner tree problem in a graph. Based on the graphical characterization, we propose both exact and reduced-complexity approximation algorithms. In particular, we show that the proposed tree-pruning based approximation algorithm significantly reduces computational complexity, while yielding negligible performance degradation compared with the optimal algorithms. The advantageous performance of the proposed defending mechanisms is verified in IEEE standard power system testcases. <s> BIB016 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> Accurate state estimation is of paramount importance to maintain the power system operating in a secure and efficient state. The recently identified coordinated data injection attacks to meter measurements can bypass the current security system and introduce errors to the state estimates. The conventional wisdom to mitigate such attacks is by securing meter measurements to evade malicious injections. In this paper, we provide a novel alternative to defend against false-data injection attacks using covert power network topological information. By keeping the exact reactance of a set of transmission lines from attackers, no false data injection attack can be launched to compromise any set of state variables. We first investigate from the attackers' perspective the necessary condition to perform injection attack. Based on the arguments, we characterize the optimal protection problem, which protects the state variables with minimum cost, as a well-studied Steiner tree problem in a graph. Besides, we also propose a mixed defending strategy that jointly considers the use of covert topological information and secure meter measurements when either method alone is costly or unable to achieve the protection objective. A mixed integer linear programming (MILP) formulation is introduced to obtain the optimal mixed defending strategy. To tackle the NP-hardness of the problem, a tree pruning-based heuristic is further presented to produce an approximate solution in polynomial time. The advantageous performance of the proposed defending mechanisms is verified in IEEE standard power system testcases. <s> BIB017 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> The widespread deployment of smart meters in the advanced metering infrastructure (AMI) raises privacy concerns. Analyzing the data collected from smart meters can expose habits and can be potentially used to predict consumers' behaviors. In this paper, we analyze the confidentiality of information in the AMI consisting of nodes with interdependent correlated security assets. On each node, the defender can choose one of several security modes available. We try to answer the following questions: 1) What is the expected behavior of a rational attacker?; 2) What is the optimal strategy of the defender?; and 3) Can we configure the security modes on each node to discourage the attacker from launching any attacks? In this paper, we formulate the problem as a noncooperative game and analyze the behavior of the attacker and the defender at the Nash equilibrium. The attacker chooses his targets in order to collect the maximum amount of data on consumers, and the defender chooses the encryption level of outbound data on each device in the AMI. Using our model, we derive the minimum defense resources required and the optimal strategy of the defender. Finally, we show how our framework can be applied in a real-world scenario via a case study. <s> BIB018 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> Cyber-Physical Security Testbeds serve as valuable experimental platforms to implement and evaluate realistic, complex cyber attack-defense experiments. Testbeds, unlike traditional simulation platforms, capture communication, control and physical system characteristics and their interdependencies adequately in a unified environment. In this paper, we show how the PowerCyber CPS testbed at Iowa State was used to implement and evaluate cyber attacks on one of the fundamental Wide-Area Control applications, namely, the Automatic Generation Control (AGC). We provide a brief overview of the implementation of the experimental setup on the testbed. We then present a case study using the IEEE 9 bus system to evaluate the impacts of cyber attacks on AGC. Specifically, we analyzed the impacts of measurement based attacks that manipulated the tie-line and frequency measurements, and control based attacks that manipulated the ACE values sent to generators. We found that these attacks could potentially create under frequency conditions and could cause unnecessary load shedding. As part of future work, we plan to extend this work and utilize the experimental setup to implement other sophisticated, stealthy attack vectors and also develop attack-resilient algorithms to detect and mitigate such attacks. <s> BIB019 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> As part of the smart grid development, more and more technologies are developed and deployed on the power grid to enhance the system reliability. A primary purpose of the smart grid is to significantly increase the capability of computer-based remote control and automation. As a result, the level of connectivity has become much higher, and cyber security also becomes a potential threat to the cyber-physical systems (CPSs). In this paper, a survey of the state-of-the-art is conducted on the cyber security of the power grid concerning issues of: (1) the structure of CPSs in a smart grid; (2) cyber vulnerability assessment; (3) cyber protection systems; and (4) testbeds of a CPS. At Washington State University (WSU), the Smart City Testbed (SCT) has been developed to provide a platform to test, analyze and validate defense mechanisms against potential cyber intrusions. A test case is provided in this paper to demonstrate how a testbed helps the study of cyber security and the anomaly detection system (ADS) for substations. <s> BIB020 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> Data injection attacks have recently emerged as a significant threat on the smart power grid. By launching data injection attacks, an adversary can manipulate the real-time locational marginal prices to obtain economic benefits. Despite the surge of existing literature on data injection, most such works assume the presence of a single attacker and assume no cost for attack or defense. In contrast, in this paper, a model for data injection attacks with multiple adversaries and a single smart grid defender is introduced. To study the defender-attackers interaction, two game models are considered. In the first, a Stackelberg game model is used in which the defender acts as a leader that can anticipate the actions of the adversaries, that act as followers, before deciding on which measurements to protect. The existence and properties of the Stackelberg equilibrium of this game are studied. To find the equilibrium, a distributed learning algorithm that operates under limited system information is proposed and shown to converge to the game solution. In the second proposed game model, it is considered that the defender cannot anticipate the actions of the adversaries. To this end, we proposed a hybrid satisfaction equilibrium - Nash equilibrium game and defined its equilibrium concept. A search algorithm is also provided to find the equilibrium of the hybrid game. Numerical results using the IEEE 30-bus system are used to illustrate and analyze the strategic interactions between the attackers and defender. Our results show that by defending a very small set of measurements, the grid operator can achieve an equilibrium through which the optimal attacks have no effect on the system. Moreover, our results show how, at equilibrium, multiple attackers can play a destructive role towards each other, by choosing to carry out attacks that cancel each other out, leaving the system unaffected. <s> BIB021 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> State estimation is an essential part of energy management system in smart grid as it is a basis for many of the associated management and control processes. In this paper, we present a decentralized state estimation approach, based on consensus optimization and the alternating direction method of multipliers, that is robust against certain harsh class of false data injection schemes. The proposed scheme provides a reliable estimate of the global system state in a distributed manner even if the system is regionally unobservable to some regional controllers, but globally observable across regions. The scheme also accommodates different communication network topologies for a given power network. We assess the performance of the presented schemes on IEEE 14 and 118 bus test systems. <s> BIB022 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> To fully support information management among various stakeholders in smart grid domains, how to establish secure communication sessions has become an important issue for smart grid environments. In order to support secure communications between smart meters and service providers, key management for authentication becomes a crucial security topic. Recently, several key distribution schemes have been proposed to provide secure communications for smart grid. However, these schemes do not support smart meter anonymity and possess security weaknesses. This paper utilizes an identity-based signature scheme and an identity-based encryption scheme to propose a new anonymous key distribution scheme for smart grid environments. In the proposed scheme, a smart meter can anonymously access services provided by service providers using one private key without the help of the trusted anchor during authentication. In addition, the proposed scheme requires only a few of computation operations at the smart meter side. Security analysis is conducted to prove the proposed scheme is secure under random oracle model. <s> BIB023 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> Advanced metering infrastructure (AMI) deployment has been widely promoted in recent years to improve the accuracy of billing information as well as to facilitate implementation of demand response. Information integrity and availability of the devices is crucial to the billing information that should reflect accurately on how much the household energy is consumed. The IP-based smart metering devices may exist with unknown vulnerabilities that can introduce backdoors to enable worm propagation across AMI network. The infected devices can be attack agents that would largely disable the metering functionalities or manipulate control variables of each meter. This paper proposes an optimal frequency of on-site investigation and the number of monitoring verification to investigate potential anomalies of malware footprinting by applying the decision process framework of Markovian. The proposed method determines the best inspection strategies based on the observation from the existing anomaly detectors deployed in the network. The considerations include malware propagation characteristics, accuracy of anomaly detectors, and investigation and diagnosis costs. Four scenarios are simulated using the proposed method, demonstrating the effectiveness of investigation on potentially infected electronic meters within an AMI network. <s> BIB024 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> Researchers from various cross disciplinary fields such as power systems, data science, and cybersecurity face two distinct challenges. First, the lack of a comprehensive test bed that integrates industry standard hardware, software, and wide area measurement system (WAMS) components and protocols impedes the study of cybersecurity issues including vulnerabilities associated with WAMS components and the consequences of exploitation of vulnerabilities. Second, a lack of comprehensive labeled Synchrophasor data along with other system related information imposes challenges to the development and evaluation of data mining algorithms that can classify power system cyber-power events. In this paper, a WAMS cyber-physical test bed was developed using a real time digital simulator with hardware-in-the-loop simulation. Commercial control and monitoring devices, hardware, software, and industry standard communication networks and protocols were combined with custom MATLAB, Python, and AutoIt scripts to model realistic power system contingencies and cyber-attacks. An automated simulation and control engine was developed to randomize modeled cyber-power events including power system faults, contingencies, control actions, and cyber-attacks. Scripts were added to capture heterogenous sensor data and create ground truth labeled datasets. The WAMS cyber-physical test bed is capable of simulating various sized power systems and creating datasets without altering the hardware configuration. A WAMS architecture is presented to document the integration of various components. Finally, test bed applications, simulated cyber-power scenarios, the dataset development process, and selected results are presented. <s> BIB025 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> This paper investigates the problem of defending against false data injection (FDI) attacks on power system state estimation. Although many research works have been previously reported on addressing the same problem, most of them made a very strong assumption that some meter measurements can be absolutely protected. To address the problem practically, a reasonable approach is to assume whether or not a meter measurement could be compromised by an adversary does depend on the defense budget deployed by the defender on the meter. From this perspective, our contributions focus on designing the least-budget defense strategy to protect power systems against FDI attacks. In addition, we also extend to investigate choosing which meters to be protected and determining how much defense budget to be deployed on each of these meters. We further formulate the meter selection problem as a mixed integer nonlinear programming problem, which can be efficiently tackled by Benders’ decomposition. Finally, extensive simulations are conducted on IEEE test power systems to demonstrate the advantages of the proposed approach in terms of computing time and solution quality, especially for large-scale power systems. <s> BIB026 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Protection <s> It was revealed that modern power systems are at high risk of cyber-attacks, as an attacker can stealthily execute false data injection attacks against the state estimation without knowing the full topology and parameter information of the entire power network. To mitigate the risk, in this paper, we propose a bilevel mixed integer linear programming (MILP) model to determine the least number of measurements to be protected. A decomposition approach is adopted to obtain the suboptimal solution. To further reduce the computation complexity, we also propose to separate the power grid into several subnetworks using a MILP approach and apply distributed protection strategy to each subnetwork. The simulations on the IEEE 14-bus, IEEE 24-bus, IEEE 30-bus, and IEEE 118-bus systems verify the correctness and effectiveness of the proposed protection strategy. <s> BIB027
Generic protection against CP attacks relies on the establishment of secured communication, the preservation of critical information, and the alleviation of exposed vulnerabilities. Since the early discussion on the challenges of cybersecurity in power systems BIB002 , innovative systems, protocols, and technologies have been developed for the protection of smart grid security. These effort have been reiterated in a number of comprehensive reviews BIB001 BIB009 BIB012  . The secure communication in smart grid can effectively dissolve a majority of the CP attack threats. While it is difficult to conduct field tests on the operating power systems, dedicated security testbeds have been developed to validate the attack schemes and facilitate the development of security enhancements BIB003 BIB004 BIB005 BIB013 BIB019 BIB020 BIB025 . A framework has also been developed to evaluate the exposure of physical components in the cyberspace BIB006 . Meanwhile, a number of attack-specific protections can be implemented strategically to reduce or erase certain CP attack threats. The threat of FDIA schemes can be effectively reduced or eliminated by the protection of a few critical measurements, as the stealthiness is dependent on the number of measurements being compromised. The protection can be achieved by the installation of secured or encrypted devices on critical locations so the protected measurements are immune to the injections. To identify these locations, greedy algorithms have been proposed to heuristically search for the critical subsets of measurements BIB007 BIB015 . Mixed-integer linear programming optimisation BIB026 BIB027 and game-theoretic approach BIB021 have been proposed with consideration of the costs of attackers and defenders, respectively. The optimal locations can also be obtained by graph-based approaches, which also provide suboptimal solutions for situations where the complexity is a major concern BIB016 . Protection strategies for critical measurements against the FDIA-based LR attacks have also been proposed in BIB008 BIB010 . Alternatively, protection against FDIA can be achieved through the preservation or rearrangement of crucial information in the system. Covert power network topological information can effectively enhance the security of SE when a subset of the line reactance has been preserved from the attacker's knowledge BIB017 . Re-configuration of the topological information in the cyberspace can also eliminate the risk of FDIA in large-scale distribution systems  . Recent development of distributed SE systems has also exhibited promising attack-resilience for the protection of SE measurements BIB022 . For the AMI systems, secure key management and distribution mechanisms have been developed as the most effective protection against unauthorised accesses to smart meters BIB014 BIB011 BIB023 . In addition, game-theoretic approach for the optimal deployment of encrypted smart meters with limited budget BIB018 and Markov decision process (MDP)-based preventative maintenance strategy BIB024 have both been developed for the protection of smart meters.