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Now-a-days, healthcare risks are more and more complex and interconnected due to the large number of agents which are meeting and interacting in this environment and due to the rapid development of technologies and information sharing. Therefore, the present paper focuses on the main healthcare risk categories and tries to qualitatively assess them using the methods offered by the grey systems theory...
Remote data possession checking plays a crucial role in cloud data storage. It allows the owners to verify whether their data are correctly stored in the Cloud without downloading them. To solve this problem, there are many methods proposed such as MAC-based methods, RSA- based homomorphic methods and BLS-based homomorphic methods.This paper presents and compares auditing methods which are based on...
This paper presents a distributed multi-agent scheme for enhancing the cyber security of smart grids which integrates computational resources, physical processes, and communication capabilities. Smart grid infrastructures are vulnerable to various cyber attacks and noises whose influences are significant for reliable and secure operations. A distributed agent-based framework is developed to investigate...
Increasing uncertainties in power system operation require novel approaches for utilizing operational flexibility to enable a both secure and efficient power supply. This paper presents a real-time coordination approach for adaptive redispatch of generation and load in case of overloads in the electrical transmission network. For this, a previously developed multi-agent system for coordinating power...
Dependency on thermal generation and continued wind power growth in Europe due to renewable energy and greenhouse gas emissions targets has resulted in an interesting set of challenges for power systems. The variability of wind power impacts dispatch and balancing by grid operators, power plant operations by generating companies and market wholesale costs. This paper quantifies the effects of high...
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...
In this paper we propose a robust method to determine, allocate and price the contingency reserves required to fully comply with N-1 security criteria in real-time operations. Unlike the traditional fixed reserve requirement, the method identifies adequate reserves in terms of type, quantity and location, needed to respond to expected generation outages. The provision of energy and responsive reserves...
This paper develops and presents an adaptive market-based load shedding scheme that provides options for adaptive selection of loads in real-time. Therefore an ancillary market-based system where consumers as well as system operator have options to contribute to system security can be evolved. All existing load shedding schemes are based on system operator's assessment and emphasize system security...
A method that exploits Thevenin equivalent representation for obtaining post-contingency steady-state nodal voltages is integrated with a method of detecting post-contingency aperiodic small-signal instability. The task of integrating stability assessment with contingency assessment is challenged by the cases of unstable post-contingency conditions. For unstable postcontingency conditions there exists...
The high penetration of distributed generation (DG) sources in distribution networks (DN) can induce overvoltage issues. In this paper, an optimal and fair real power capping method (RPCM) for voltage regulation in DN with high photovoltaic (PV) penetration is proposed. Based on the forecasting of solar radiance and load profiles, the method optimally dispatches the generation of PVs to prevent overvoltage...
Renewable energy sources and widespread small-scale power generators change the structure of the power grid, where actual power consumers also temporarily become suppliers. Smart grids require continuous management of complex operations through utility providers, which leads to increasing interconnections and usage of ICT-enabled industrial control systems. Yet, often insufficiently implemented security...
A Smart Transformers (ST) is an automated transformer based on the latest power electronics and communication technologies. It aims not only at replacing the traditional transformer, but at providing also ancillary services to the grid, thanks to the greater flexibility offered by power electronics. However, in the case of grid overload caused by high load demand or high production from renewable...
This paper presents a model to include a security constraint for wind power plant in a hydrothermal dispatch problem. The proposed Unit Commitment (UC) is an augmented problem to take into account different scenarios of wind speed during the day. The wind farms are represented by a linear model that the generations are considered proportional to the availability of wind. The proposed optimization...
nowadays, power system tends to be operated in heavily stressed load, which can cause voltage stability problem. Moreover, occurrence probability of contingency is increasing due to growth of power system size and complexity. This paper proposes a new preventive control scheme based on voltage stability and security monitoring by means of wide area monitoring systems (WAMS). The proposed control scheme...
Risk-based security indexes can be used as a constraint in OPF to determine the most economic generation dispatch while ensuring that the risk of power system operation stays below a given value. Existing approaches only limit the total risk, which can result in some system states having significantly higher values of risk compared to others. In this paper, a risk-constrained AC OPF that limits the...
In this paper an algorithm is developed for solving the Optimal Power Flow (OPF) and Security Constrained OPF (SCOPF) problem in mixed AC/DC grids. Non-linear models are used for power lines and AC/DC and DC/DC converters. The converter models include terminal losses and power rating constraints. The formulation of the SCOPF problem is such that it works for preventive OPF where no corrective actions...
With rapidly increasing complexity of power grids in Europe, North America and Asia, liberalization of electricity markets and increasing penetration of renewable energy, the risk of large-scale emergencies and blackouts increases. This paper proposes a novel approach for development of software for modelling of decentralized intelligent systems for security monitoring and control in power systems...
Scan based Design for Testability structures are highly vulnerable to unauthorized access to the internal signals of a chip. This paper proposes a secure scan based design which prevents this unauthorized access without any compromise in the testability. The proposed secure architecture employs unique keys for each test vector. These unique keys are generated by a linear feedback shift register and...
Voltage collapse is a critical problem that impacts power system operational security. Timely and accurate assessment of voltage security is necessary to detect alarm states in order to prevent a large-scale blackout. This paper presents an on-line voltage security assessment scheme using periodically updated random forest-based decision trees. We demonstrated the proposed method on the modified 53-bus...
This paper discusses some problems related with the current Brazilian electricity market, brings out some dilemmas that should be examined in order to implement a more market oriented approach, and proposes a new market design to overcome these issues. The proposed market design is based on the concept of energy right accounts as virtual reservoirs and aims at enhancing the flexibility to enable market...
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