330,512 research outputs found

    Dispersed storage and generation case studies

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    Three installations utilizing separate dispersed storage and generation (DSG) technologies were investigated. Each of the systems is described in costs and control. Selected institutional and environmental issues are discussed, including life cycle costs. No unresolved technical, environmental, or institutional problems were encountered in the installations. The wind and solar photovoltaic DSG were installed for test purposes, and appear to be presently uneconomical. However, a number of factors are decreasing the cost of DSG relative to conventional alternatives, and an increased DSG penetration level may be expected in the future

    Concepts for design of an energy management system incorporating dispersed storage and generation

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    New forms of generation based on renewable resources must be managed as part of existing power systems in order to be utilized with maximum effectiveness. Many of these generators are by their very nature dispersed or small, so that they will be connected to the distribution part of the power system. This situation poses new questions of control and protection, and the intermittent nature of some of the energy sources poses problems of scheduling and dispatch. Under the assumption that the general objectives of energy management will remain unchanged, the impact of dispersed storage and generation on some of the specific functions of power system control and its hardware are discussed


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    Distribution networks are undergoing radical changes due to the high level of penetration of dispersed generation. Dispersed generation systems require particular attention due to their incorporation of uncertain energy sources, such as wind farms, and due to the impacts that such sources have on the planning and operation of distribution networks. In particular, the foreseeable, extensive use of wind turbine generator units in the future requires that distribution system engineers properly account for their impacts on the system. Many new technical considerations must be addressed, including protection coordination, steady-state analysis, and power quality issues. This paper deals with the very short-term, steady-state analysis of a distribution system with wind farms, for which the time horizon of interest ranges from one hour to a few hours ahead. Several wind-forecasting methods are presented in order to obtain reliable input data for the steady-state analysis. Both deterministic and probabilistic methods were considered and used in performing deterministic and probabilistic load-flow analyses. Numerical applications on a 17-bus, medium-voltage, electrical distribution system with various wind farms connected at different busbars are presented and discusse

    Cavity-enhanced single frequency synthesis via DFG of mode-locked pulse trains

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    We show how to synthesize a CW, single-frequency optical field from the frequency-dispersed, pulsed field of a mode-locked laser. This process, which relies on difference frequency generation in an optical cavity, is efficient and can be considered as an optical rectification. Quantitative estimates for the output power and amplitude noise properties of a realistic system are given. Possible applications to optical frequency synthesis and optical metrology are envisaged

    Distributed monitoring and control of future power systems via grid computing

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    It is now widely accepted within the electrical power supply industry that future power systems operates with significantly larger numbers of small-scale highly dispersed generation units that use renewable energy sources and also reduce carbon dioxide emissions. In order to operate such future power systems securely and efficiently it will be necessary to monitor and control output levels and scheduling when connecting such generation to a power system especially when it is typically embedded at the distribution level. Traditional monitoring and control technology that is currently employed at the transmission level is highly centralized and not scalable to include such significant increases in distributed and embedded generation. However, this paper proposes and demonstrates the adoption of a relatively new technology 'grid computing' that can provide both a scalable and universally adoptable solution to the problems associated with the distributed monitoring and control of future power systems

    Hourly Reconfiguration of Large-scale Networks in the Presence of Dispersed generations Based on Changes in Load and Generation Levels with Teaching-Learning Based Optimization Algorithm

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    Reconfiguration of distribution networks is a problem related to exploitation that, due to changes in the mode of switches, causes changes in configuration of distributed feeders to achieve optimal topology in order to minimize network losses. In addition, dispersed generation units play an important role in distribution networks. The present study aims to examine the reconfiguration of distribution networks by considering the effect of changes in generation level of dispersed generation units and also in load levels with Teaching-Learning Based Optimization (TLBO) Algorithm in order to reduce network power losses. Given the fact that presence of dispersed generation units has a significant effect on reducing network losses, it is necessary to extract optimal topologies in the presence of, in the absence of, and based on the changes in the generation level of these units. In this study, analysis of performance is presented on a standard 69-bus distribution network and effectiveness of the proposed method is proven. Also, some part of the real network of Ardabil with two sub-transmission posts and 5 medium-pressure feeders is analyzed as a large-scale network. The simulation results show that reduction of power losses and improvement of the voltage profile in distribution networks are achieved with the presence of dispersed generation units and also reconfiguration of the distribution network