11,872 research outputs found

    Impact Assessment of Hypothesized Cyberattacks on Interconnected Bulk Power Systems

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    The first-ever Ukraine cyberattack on power grid has proven its devastation by hacking into their critical cyber assets. With administrative privileges accessing substation networks/local control centers, one intelligent way of coordinated cyberattacks is to execute a series of disruptive switching executions on multiple substations using compromised supervisory control and data acquisition (SCADA) systems. These actions can cause significant impacts to an interconnected power grid. Unlike the previous power blackouts, such high-impact initiating events can aggravate operating conditions, initiating instability that may lead to system-wide cascading failure. A systemic evaluation of "nightmare" scenarios is highly desirable for asset owners to manage and prioritize the maintenance and investment in protecting their cyberinfrastructure. This survey paper is a conceptual expansion of real-time monitoring, anomaly detection, impact analyses, and mitigation (RAIM) framework that emphasizes on the resulting impacts, both on steady-state and dynamic aspects of power system stability. Hypothetically, we associate the combinatorial analyses of steady state on substations/components outages and dynamics of the sequential switching orders as part of the permutation. The expanded framework includes (1) critical/noncritical combination verification, (2) cascade confirmation, and (3) combination re-evaluation. This paper ends with a discussion of the open issues for metrics and future design pertaining the impact quantification of cyber-related contingencies

    Parallel and Distributed Simulation from Many Cores to the Public Cloud (Extended Version)

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    In this tutorial paper, we will firstly review some basic simulation concepts and then introduce the parallel and distributed simulation techniques in view of some new challenges of today and tomorrow. More in particular, in the last years there has been a wide diffusion of many cores architectures and we can expect this trend to continue. On the other hand, the success of cloud computing is strongly promoting the everything as a service paradigm. Is parallel and distributed simulation ready for these new challenges? The current approaches present many limitations in terms of usability and adaptivity: there is a strong need for new evaluation metrics and for revising the currently implemented mechanisms. In the last part of the paper, we propose a new approach based on multi-agent systems for the simulation of complex systems. It is possible to implement advanced techniques such as the migration of simulated entities in order to build mechanisms that are both adaptive and very easy to use. Adaptive mechanisms are able to significantly reduce the communication cost in the parallel/distributed architectures, to implement load-balance techniques and to cope with execution environments that are both variable and dynamic. Finally, such mechanisms will be used to build simulations on top of unreliable cloud services.Comment: Tutorial paper published in the Proceedings of the International Conference on High Performance Computing and Simulation (HPCS 2011). Istanbul (Turkey), IEEE, July 2011. ISBN 978-1-61284-382-

    Power quality and electromagnetic compatibility: special report, session 2

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    The scope of Session 2 (S2) has been defined as follows by the Session Advisory Group and the Technical Committee: Power Quality (PQ), with the more general concept of electromagnetic compatibility (EMC) and with some related safety problems in electricity distribution systems. Special focus is put on voltage continuity (supply reliability, problem of outages) and voltage quality (voltage level, flicker, unbalance, harmonics). This session will also look at electromagnetic compatibility (mains frequency to 150 kHz), electromagnetic interferences and electric and magnetic fields issues. Also addressed in this session are electrical safety and immunity concerns (lightning issues, step, touch and transferred voltages). The aim of this special report is to present a synthesis of the present concerns in PQ&EMC, based on all selected papers of session 2 and related papers from other sessions, (152 papers in total). The report is divided in the following 4 blocks: Block 1: Electric and Magnetic Fields, EMC, Earthing systems Block 2: Harmonics Block 3: Voltage Variation Block 4: Power Quality Monitoring Two Round Tables will be organised: - Power quality and EMC in the Future Grid (CIGRE/CIRED WG C4.24, RT 13) - Reliability Benchmarking - why we should do it? What should be done in future? (RT 15

    A guide for performing system safety analysis

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    A general guide is presented for performing system safety analyses of hardware, software, operations and human elements of an aerospace program. The guide describes a progression of activities that can be effectively applied to identify hazards to personnel and equipment during all periods of system development. The general process of performing safety analyses is described; setting forth in a logical order the information and data requirements, the analytical steps, and the results. These analyses are the technical basis of a system safety program. Although the guidance established by this document cannot replace human experience and judgement, it does provide a methodical approach to the identification of hazards and evaluation of risks to the system

    Chip level simulation of fault tolerant computers

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    Chip level modeling techniques, functional fault simulation, simulation software development, a more efficient, high level version of GSP, and a parallel architecture for functional simulation are discussed

    Risk-based assessment for distribution network via an efficient Monte Carlo simulation model

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    Given the fact that Smart Grid technologies are implemented mainly in distribution networks, it is essential to build a risk-based assessment tool which can model the operational characteristics of distribution networks operation. This thesis presented a distribution network model which captures the features of distribution network restoration, based on approximations of real-time switching actions. It enables the evaluation of complex distribution network reliability with active network control. The development of an explicit switching model which better reflects actual network switching actions allows for deliberate accuracy and efficiency trade-offs. Combined with importance sampling approach, a significant improvement in computational efficiency has been achieved with both simplified and detailed network switching models. The assessment model also provides flexibility for users to analyse system reliability with various levels of complexity and efficiency. With the proposed assessment tool, different network improvement technologies were investigated for their values of substituting traditional network constructions and impacts on network reliability performances. It has been found that a combination of different technologies, according to specific network requirements, provide the best solution to network investments. Models of customer interruption cost were analysed and compared. The study shows that using different cost models will result in large differences in results and lead to different investment decisions. A single value of lost load is not appropriate to achieve an accurate interruption cost quantification. A chronological simulation model was also built for evaluating the implications of High Impact Low Probability events on distribution network planning. This model provides the insights for the cost of such events and helps network planners justify the cost-effectiveness of post-fault corrections and preventive solutions. Finally, the overall security of supply for GB system was assessed to investigate the impacts of a recent demand reduction at grid supply points (for transmission networks) resulting from the fast growing of generation capacity in distribution networks. It has been found that the current security standard may not be able to guarantee an acceptable reliability performance with the increasing penetration of distributed generation, if further balancing service investment is not available.Open Acces
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