다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

(1990). ENERGY FUNCTION ANALYSIS FOR POWER SYSTEM STABILITY. Electric Machines & Power Systems: Vol. 18, No. 2, pp. 209-210.

Energy function analysis for power system stability

The smart grid is arguably one of the most complex cyber-physical systems (CPS). Complex security challenges have been revealed in both the physical and the cyber parts of the smart grid, and an integrative analysis on the cyber-physical (CP) security is emerging. This paper provides a comprehensive and systematic review of the critical attack threats and defence strategies in the smart grid. We start this survey with an overview of the smart grid security from the CP perspective, and then focuses on prominent CP attack schemes with significant impact on the smart grid operation and corresponding defense solutions. With an in-depth review of the attacks and defences, we then discuss the opportunities and challenges along the smart grid CP security. We hope this paper raises awareness of the CP attack threats and defence strategies in complex CPS-based infrastructures such as the smart grid and inspires research effort toward the development of secure and resilient CP infrastructures.

Cyber-physical attacks and defences in the smart grid: a survey

Cyber security of a power grid: State-of-the-art

Cyber-security in smart grid: Survey and challenges

As information and communication networks are highly interconnected with the power grid, cyber security of the supervisory control and data acquisition (SCADA) system has become a critical issue in the electric power sector. By exploiting the vulnerabilities in cyber components and intruding into the local area networks of the control center, corporation, substations, or by injecting false information into communication links, the attackers are able to eavesdrop critical data, reconfigure devices, and send trip commands to the intelligent electronic devices that control the system breakers. Reliability of the power system can thus be impacted by various cyber attacks. In this paper, four attack scenarios for cyber components in networks of the SCADA system are considered, which may trip breakers of physical components. Two Bayesian attack graph models are built to illustrate the attack procedures and to evaluate the probabilities of successful cyber attacks. A mean time-to-compromise model is modified and adopted considering the known and zero-day vulnerabilities on the cyber components, and the frequencies of intrusions through various paths are estimated. With increased breaker trips resulting from the cyber attacks, the loss of load probabilities in the IEEE reliability test system 79 are estimated. The simulation results demonstrate that the power system becomes less reliable as the frequency of successful attacks on the cyber components increases and the skill levels of attackers increase.

Power System Reliability Evaluation With SCADA Cybersecurity Considerations

Coordinated attacks on electric power systems in a cyber-physical environment

By exploiting the vulnerabilities in cyber components, an attacker could intrude in the wind farm supervisory control and data acquisition (SCADA) system and energy management system (EMS), and maliciously trip one or multiple wind turbines. The reliability of the overall power system could thus be impacted by the performance of wind farms. In this paper, cyber attack scenarios concerning cyber components or networks are considered in the integrated wind farm SCADA/EMS system architecture. Two Bayesian attack graph models are adopted to represent the procedures of successful cyber attacks, and a mean time-to-compromise model is used by considering different attack levels and various vulnerabilities. Frequencies of successful cyber attacks on the wind farm SCADA/EMS system are estimated. A procedure for evaluating the power system reliability is proposed by considering wind turbine trips caused by various cyber attacks. Simulations are conducted based on a typical IEEE reliability test system. Simulation results indicate that the overall system reliability decreases when the frequency of successful attacks on the wind farm SCADA/EMS system and skill levels of attackers increase.

Power System Reliability Assessment Incorporating Cyber Attacks Against Wind Farm Energy Management Systems

The increased complexity of power system makes the power dispatch heavily rely on the condition monitoring and state estimation functions. However, with the massive deployment of cyber technologies, the power grid is becoming more vulnerable to malicious cyber attacks, including various kinds of false data injection attacks. This paper quantifies the influence of load redistribution (LR) attack on the long-term power supply reliability. The intrusion process for manipulating the measurements is modeled by the semi-Markov models. Considering the practical cross-check for suspicious measurements, the regional LR attack model is proposed. A holistic framework incorporating the physical failures and the LR attack is proposed for cyber-physical power system reliability evaluation. The simulation is carried out on the IEEE RTS79 system. The influences of critical factors and strategies are analyzed. It is concluded that the LR attacks have a non-negligible impact on the power system reliability.

Power System Reliability Evaluation Considering Load Redistribution Attacks

A piecewise analytical function is proposed and applied to investigate the steady-state behavior of series-parallel resonant converter operated in a discontinuous current mode. The converter shows two sequences of the equivalent circuits alternatively operated in the discontinuous current mode with different output voltages. To get the response time of current in one resonance, a successive solving process based on the state-space method is presented analytically in each sequence. This solving process can describe the complicated behavior resulting from the load rectifier, which makes the output capacitor appear or disappear several times in one switching period. By introducing the output voltage coefficient and the principle of energy transmission balance, the steady-state model is deduced afterward. This model is accurate and simple, making it helpful to design and optimize the converter conveniently. An excellent agreement is obtained when comparing numerical values calculated by the proposed model to the simulation and to the experimental results.

Yingmeng Xiang

Papers

Power System Reliability Evaluation With SCADA Cybersecurity Considerations

Coordinated attacks on electric power systems in a cyber-physical environment

Power System Reliability Assessment Incorporating Cyber Attacks Against Wind Farm Energy Management Systems

Power System Reliability Evaluation Considering Load Redistribution Attacks

An Analytical Steady-State Model of LCC type Series–Parallel Resonant Converter With Capacitive Output Filter