Cyber-physical attacks and defences in the smart grid: a survey <s> Substation attacks: <s> 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. <s> BIB001 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Substation attacks: <s> Power station control and management systems represent key elements for guaranteeing the security of the power grid infrastructure. Intrinsically conceived to support the continuous provision of power in secure conditions, those systems today make intensive use of information and communication systems and are therefore exposed to related accidental and intentional cyber threats. This paper describes a simulation of cyber attacks conducted in the CESI RICERCA laboratory testbed on a prototypical substation control infrastructure with the purpose of testing their feasibility and illustrating their impact on the control system services. A set of attack scenarios targeting several subsystems has been experimented, with different simulated threat motivations and different degrees of impact on the global substation service. The paper reports some considerations about the consequences of the implemented attacks, focusing on different facets of the problem, in an effort to elucidate the full significance of the potential cyber threats. <s> BIB002 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Substation attacks: <s> 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 scenario of simultaneous intrusions launched over multiple substations is considered. The proposed detection method considers temporal 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. <s> BIB003 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Substation attacks: <s> A modern power system consists of several control and monitoring loops, both automated and manually operated, to ensure that the system remains within safe operating bounds at all times. The focus of this paper is on data integrity attacks on messages exchanged between the control center and actuators in the voltage control loop. Devices such as the ones belonging to the FACTS family (STATCOM, SVC, TCR, etc.), are connected to the system at designated points for voltage control purposes. An attacker could cause a detrimental impact on the system by performing an attack on the control messages sent to these devices which would manipulate its settings. The aim of this paper is to highlight the impact of an attack targeted at such voltage control deices in the system. This paper presents a template that might be used by an attacker with knowledge of system functionality. The paper also explains the sensitivity analysis technique which will help the attacker identify the device to be compromised. A successful attack would result in abnormal voltage conditions in the system, thus violating NERC reliability standards. <s> BIB004 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Substation attacks: <s> In the study of power grid security, the cascading failure analysis in multi-contingency scenarios has been a challenge due to its topological complexity and computational cost. Both network analyses and load ranking methods have their own limitations. In this paper, based on self-organizing map (SOM), we propose an integrated approach combining spatial feature (distance)-based clustering with electrical characteristics (load) to assess the vulnerability and cascading effect of multiple component sets in the power grid. Using the clustering result from SOM, we choose sets of heavy-loaded initial victims to perform attack schemes and evaluate the subsequent cascading effect of their failures, and this SOM-based approach effectively identifies the more vulnerable sets of substations than those from the traditional load ranking and other clustering methods. As a result, this new approach provides an efficient and reliable technique to study the power system failure behavior in cascading effect of critical component failure. <s> BIB005 </s> Cyber-physical attacks and defences in the smart grid: a survey <s> Substation attacks: <s> The cyber-security of several industrial plants has been compromised for last years by some worms and viruses, such as Stuxnet, which was able to take control of the Supervisory Control And Data Acquisition (SCADA) system of a nuclear plant in Iran. The research community and the international standardization committees raised their awareness about protecting information in Substation Automation Systems (SAS). IEC 61850-5 and IEC 62351-6 standards respectively describe communication models and the security mechanisms to be deployed in current substations, but they present some inconsistencies. On the one hand, this standard mandates that RSA cryptosystem must be used to provide source authenticity of GOOSE and SV messages. However, despite expensive processors with crypto accelerators were utilized, execution times would exceed the maximum transfer times stated in the standard for most time critical applications. On the other hand, the recommended synchronization solution is the Precision Time Protocol (PTP), as defined in IEEE 1588-2008, which introduced an optional security extension based on old keyed hash algorithms that has also been demonstrated to be suboptimal due to latency times and required resources. The aim of this paper is to explore current available security solutions and study their applicability to the substation environment. Furthermore, as part of the future security framework, a MACsec-based security approach that allows different communication services with diverse performance and security requirements to live together within the substation network is proposed. <s> BIB006
in operation across the USA, the entire interconnected transmission system could suffer a major blackout when coordinated attacks had been launched on as few as nine transmission substations  . An early investigation on substation network security has demonstrated that an attacker is capable of penetrating multi-layers of firewalls and password protections to gain full control of a substation BIB001 . Credible impacts of multi-substation intrusions have been subsequently evaluated in BIB003 , and the potential risks given consideration of cascading failures under multi-substation attacks have been demonstrated in BIB005 . As shown in Fig. 5 , the clustering-based vulnerability analysis can effectively identify the most-vulnerable victims in a bulk power grid. Within a compromised substation, the voltage control loop of flexible alternating current (AC) transmission system becomes vulnerable to malicious attacks  . Malicious messages can be injected to manipulate the configuration of the voltage controllers that results in voltage violations and oscillations in the system BIB004 . Detailed simulations of typical substation attacks have been conducted in BIB002 , and the cybersecurity issues of substation automation systems have been comprehensively analysed  BIB006 .