23,387 research outputs found

    Power system security enhancement by HVDC links using a closed-loop emergency control

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    In recent years, guaranteeing that large-scale interconnected systems operate safely, stably and economically has become a major and emergency issue. A number of high profile blackouts caused by cascading outages have focused attention on this issue. Embedded HVDC (High Voltage Direct Current) links within a larger AC power system are known to act as a “firewall” against cascading disturbances and therefore, can effectively contribute in preventing blackouts. A good example is the 2003 blackout in USA and Canada, where the Québec grid was not affected due to its HVDC interconnection. In the literature, many works have studied the impact of HVDC on the power system stability, but very few examples exist in the area of its impact on the system security. This paper presents a control strategy for HVDC systems to increase their contribution to system security. A real-time closed-loop control scheme is used to modulate the DC power of HVDC links to alleviate AC system overloads and improve system security. Simulations carried out on a simplified model of the Hydro-Québec network show that the proposed method works well and can greatly improve system security during emergency situations.Peer reviewedFinal Accepted Versio

    Age-appropriate information technology on the advance: Putting paid to olden times

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    Ageing society opens up enormous economic potential. Whereas for a long time social interpretation homed in on the doomsday scenarios of demographic change, it is the economic potential that is now emerging with increasing clarity. Information and communication technologies stand a good chance of benefiting from this trend. Older people are not intrinsically technology refuseniks, as evidenced by the growing number of silver agers using the internet. Successful products will be far removed from disenfranchisement and stigmatisation. The challenge to product developers and marketing strategists is to create age-appropriate offers that older people do not perceive as encroaching on their autonomy or pointing up their physical infirmities. Particularly promising are offers enabling barrier-free use without seeming like segregational solutions for specific age groups. User friendliness, value systems and the legal framework are currently stymieing yet wider success. Technical fascination aside, the business potential hinges directly on regulations concerning data protection, teletreatment and cost reimbursement, on user friendliness and society’s attitude towards the application of robotics in medicine and healthcare. The tasks involved are enormous. Product developers, marketing strategists, physicians, nurses and carers, politicians and older people in need of help themselves must be prepared to take the new routes. Assistance systems, e-Health and health games benefit from demographic change. The range of offers is highly diversified. They extend from ‘intelligent’ tablet dispensers, emergency bio sensor technology in motor vehicles and motion sensor technology through tele-monitoring and online consultations to brain jogging and exercise games.demographics, technology,ICT, e-Health, games, AAL, assistance systems

    Automating security monitoring and analysis for Space Station Freedom's electric power system

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    Operating a large, space power system requires classifying the system's status and analyzing its security. Conventional algorithms are used by terrestrial electric utilities to provide such information to their dispatchers, but their application aboard Space Station Freedom will consume too much processing time. A new approach for monitoring and analysis using adaptive pattern techniques is presented. This approach yields an on-line security monitoring and analysis algorithm that is accurate and fast; and thus, it can free the Space Station Freedom's power control computers for other tasks

    A design for an intelligent monitor and controller for space station electrical power using parallel distributed problem solving

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    The emphasis is on defining a set of communicating processes for intelligent spacecraft secondary power distribution and control. The computer hardware and software implementation platform for this work is that of the ADEPTS project at the Johnson Space Center (JSC). The electrical power system design which was used as the basis for this research is that of Space Station Freedom, although the functionality of the processes defined here generalize to any permanent manned space power control application. First, the Space Station Electrical Power Subsystem (EPS) hardware to be monitored is described, followed by a set of scenarios describing typical monitor and control activity. Then, the parallel distributed problem solving approach to knowledge engineering is introduced. There follows a two-step presentation of the intelligent software design for secondary power control. The first step decomposes the problem of monitoring and control into three primary functions. Each of the primary functions is described in detail. Suggestions for refinements and embelishments in design specifications are given

    ITERL: A Wireless Adaptive System for Efficient Road Lighting

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    This work presents the development and construction of an adaptive street lighting system that improves safety at intersections, which is the result of applying low-power Internet of Things (IoT) techniques to intelligent transportation systems. A set of wireless sensor nodes using the Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 standard with additional internet protocol (IP) connectivity measures both ambient conditions and vehicle transit. These measurements are sent to a coordinator node that collects and passes them to a local controller, which then makes decisions leading to the streetlight being turned on and its illumination level controlled. Streetlights are autonomous, powered by photovoltaic energy, and wirelessly connected, achieving a high degree of energy efficiency. Relevant data are also sent to the highway conservation center, allowing it to maintain up-to-date information for the system, enabling preventive maintenance.Consejería de Fomento y Vivienda Junta de Andalucía G-GI3002 / IDIOFondo Europeo de Desarrollo Regional G-GI3002 / IDI
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