CYBER-PHYSICAL SYSTEMS SECURITY FOR THE SMART GRID
A. C´ardenas , R. Moreno, “Cyber-Physical Systems security for the Smart Grid,” CPS Workshop 2011.
The authors focus on giving a brief overview of why traditional security mechanisms for power systems are inadequate and the need for CPS security. They briefly describe the functional areas of the grid: State estimation-need for SE, mathematically modeling it, testing bad measurements. Constructing the network topology based on data from sensors. Electricity markets-describing the need and the association with SE. Control signals sent to automatic devices/equipment in the grid , based on processed data. The work surveyed is mainly about false data injection attacks and defense at different functional stages of the power systems if present and they open discussions . The authors in a broad sense describe only the principle of the works. They discuss limitations that they find in the works that have surveyed and talk about problems and challenges that have not been covered in literature previously. The authors do not provide a specific solution to the security problem , however, they provide general suggestions on what CPS defense mechanisms could focus on.
FUNCTIONS IN THE CYBER LAYER OF THE GRID
Collecting information from sensors and constructing a model. State estimation of the power system based on measurements Computation and delivery of LMPs(Locational marginal pricing (LMP) is a mechanism for using market-based prices for managing transmission congestion .It involves the marginal cost of supplying ,at least cost, t he next increment of electric demand at a location along with other factors.) for electricity markets Transmission automation-control signals sent to automated devices in the grid The authors survey recent work, find limitations and present them. They discuss open problems and challenges in new research in areas of EMS that have not been considered previously. However, they do not specifically present any solution of their own.
The authors differentiate attacks and defense mechanisms based on the functional areas of the cyber layer that they are designed to attack. All the attacks are primarily based on false data injection. Liu et al-State estimation area, study of attacks on sensors without detection Kosut et al-State estimation area, considers attackers trying to maximize error. Not specifically discussed whether sensors are compromised or not. Also considers defense algorithms designed to detect network attacks. Superior and different as compared to previous fault detection algorithms. Dan and Sandberg -State estimation area, differs from work by Liu et al. because they assume that the attacker cannot compromise sensors .
COMPARING AND CONTRASTING METHODS
References:Y. Liu, M. K. Reiter, and P. Ning. False data injection attacks against state estimation in electric power grids. In CCS ’09: Proceedings of the 16th ACM conference on Computer and communications security, pages 21–32, New York, NY, USA, 2009. ACM.  O. Kosut, L. Jia, R. Thomas, and L. Tong. Malicious Data Attacks on Smart Grid State Estimation: Attack Strategies and Countermeasures. In First IEEE Smart Grid Commnunications Conference (SmartGridComm), October 2010.  G. D´an and H. Sandberg. Stealth Attacks and Protection Schemes for State Estimators in Power Systems. In First
IEEE Smart Grid Commnunications Conference (SmartGridComm), October 2010.
COMPARING AND CONTRASTING METHODS-contd.
Xie. et al.-Electricity markets area, Differs from other work surveyed here because Xie et. al considers the motive of “selfish attacker” and not a “malicious attacker”. Negrete-Pincetic et al- Electricity markets area ,Differs from other work surveyed because they consider attacks against control signals. Earlier attacks are against sensor signals. Philips et al- Transmission automation area,...
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