1,721,004 research outputs found
Visualization techniques of Online Risk-Based Security Assessment (OL-RBSA) application
Get PDFIn a power system control room, operators monitor the power system security to ensure that the bulk electric power systems can withstand sudden disturbances such as electric short circuits or unforeseen loss of system elements - transmission lines, generators, transformers, or loads. There are three types of problems that can result from these disturbances: circuit overload, voltage problems, and dynamic problems. The responsibilities of operational decision-makers are stressful, as the decisions they make, if in error, may result in catastrophic consequences. To ensure that the operations are economic and secure, a probabilistic risk approach called On-Line Risk Based Security Assessment (OL-RBSA) was developed to compute indices that characterize the system security levels. But a key drawback to this approach is that system operators are not able to assimilate the resulting numerical information under stressed conditions in a short time frame. Therefore, the research presented in this thesis has developed visualization techniques for the numerical data. These techniques help human decision-makers to generate immediate insights from the results, especially in stressful environments. The risk indices are visualized using a number of approaches, including relational graphics (meters and bar charts to illustrate risk level), nomograms to illustrate risk variation with operating conditions, temporally, using risk-time plots, and spatially, using a Geographic Information System (GIS) to illustrate the risk indices on a geographic one-line diagram of the transmission system. A remote database management system was a key technology employed in this work to facilitate data movement from the risk calculation engine to the visualization modules
Distribution Emergency Operation
No full textReducing power outage time to each customer is essential to the overall distribution reliability. This book provides the fundamentals of emergency operation using a graph-theoretic approach and exploration of the subsystem(s) that address the operational aspects of electrical fault occurrence to determine possible feeder reconfiguration. The localization of a faulted segment within a feeder involves remote-controlled normally open (NO) and normally closed (NC) switches through supervisory control and data acquisition (SCADA) between radially energized, interconnected feeders. Topics cover: (1) Data extraction from geographic information systems (GIS), (2) Graph modeling of distribution feeders, (3) Programming for backward/forward sweeping unbalanced power flow, (4) Short circuit analysis and fault localization, (5) Fault isolation, temporary and full service restoration, (6) Outage management and crew coordination, (7) Trouble call tickets and escalation to search for fault, and (8) Emerging subject of distribution management systems (DMS)
Preventative maintenance for advanced metering infrastructure against malware propagation
No full textAdvanced metering infrastructure (AMI) deployment has been widely promoted in recent years to improve the accuracy of billing information as well as to facilitate implementation of demand response. Information integrity and availability of the devices is crucial to the billing information that should reflect accurately on how much the household energy is consumed. The IP-based smart metering devices may exist with unknown vulnerabilities that can introduce backdoors to enable worm propagation across AMI network. The infected devices can be attack agents that would largely disable the metering functionalities or manipulate control variables of each meter. This paper proposes an optimal frequency of on-site investigation and the number of monitoring verification to investigate potential anomalies of malware footprinting by applying the decision process framework of Markovian. The proposed method determines the best inspection strategies based on the observation from the existing anomaly detectors deployed in the network. The considerations include malware propagation characteristics, accuracy of anomaly detectors, and investigation and diagnosis costs. Four scenarios are simulated using the proposed method, demonstrating the effectiveness of investigation on potentially infected electronic meters within an AMI network
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Strategic FRTU deployment considering cybersecurity in secondary distribution network
No full textThis paper is concerned about strategic deployment of feeder remote terminal unit (FRTU) in primary network by considering cybersecurity of distribution secondary network. First, detection of historical anomaly load profile in secondary network is assumed to be observable. These irregularities of historical energy usages can be determined from consumer billing centers using proposed cybersecurity metrics. While it is constrained by budget on the number of FRTUs that can be deployed, the proposed algorithm identifies pivotal locations of a distribution feeder to install the FRTUs in different time horizons. The simulation results show that the infrastructure enhancement using proposed multistage method improves investment planning for distribution systems. © 2010-2012 IEEE
Determination of Nash Equilibrium Based on Plausible Attack-Defense Dynamics
No full text© 1969-2012 IEEE. In the critical infrastructure domain, there exist two distinct players, i.e., attackers and defenders, with contradictory strategies to achieve their winnings. This paper proposes a game-theoretic approach to capture the plausible attack-defense dynamics for power transmission grids in a controlled environment. The stratagems of attackers and defenders can be modeled with unique attributes of their motives and emergency responses. The behaviors of attackers include observation and disruptive actions that can disturb operation while defenders can establish multiple levels of defense with remedial actions for risk mitigation. With an assumption of complete information, the defenders can minimize expected loss of load and generator tripping with load generation adjustment based on current conditions. The attackers, which represent the other force, can maximize their payoff by deploying persistent agents to target on the specific points within a power operation network. The boundary between these two, referred as subgame perfect Nash equilibrium, is proposed in the dynamic game model. This model initiates an original infinite game tree that is converted into a finite structure, which is solved using a backward induction approach with multiple scenario validations
Cyber-Based Contingency Analysis
No full text© 2016 IEEE. Microprocessor-based relays protecting against fault current have revolutionized power automation industry. The leverage using commercially available information communication technologies has been the currency for future cyberinfrastructure deployment, which enables plausible electronic manipulation that can affect system operation. The bus differential protection has been recognized as one of the most critical protection schemes, if compromised, that would disconnect a large number of components within a substation. A hypothesized substation outage is the worst case scenario of intrusion attack events. This paper proposes an impact analysis of critical cyber assets in substations that capture historical load and topology conditions. This is to identify critical substations and other \u27nightmare\u27 hypothesized combinations for security protection planning. The proposed metrics of attack scenarios incorporate electronic instrumentation in relation to the physical system for impact and dependency evaluation. Combinatorial verification of these hypothesized events based on the proposed reverse pyramid model (RPM) is validated using IEEE 30-and 118-bus systems
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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