549 research outputs found

    Modified Taguchi-Based Approach for Optimal Distributed Generation Mix in Distribution Networks

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    In this paper, a new two-stage optimization framework is proposed to determine the optimal-mix integration of dispatchable Distributed Generation (DG), in power distribution networks, in order to maximize various techno-economic and social benefits simultaneously. The proposed framework incorporates some of the newly introduced regulatory policies to facilitate low carbon networks. A modified Taguchi Method (TM), in combination with a node priority list, is proposed to solve the problem in a minimum number of experiments. Nevertheless, the standard TM is computationally fast but has some inherent tendencies of local trapping and usually converges to suboptimal solutions. Therefore, two modifications are suggested. A roulette wheel selection criterion is applied on priority list to select the most promising DG nodes and then modified TM determines the optimal DG sizes at these nodes. The proposed approach is implemented on two standard test distribution systems of 33 and 118 buses. To validate the suggested improvements, various algorithm performance parameters such as convergence characteristic, best and worst fitness values, and standard deviation are compared with existing variants of TM, and improved genetic algorithm. The comparison shows that the suggested corrections significantly improve the robustness and global searching ability of TM, even compared to meta-heuristic methods

    Mobile Power Infrastructure Planning and Operational Management for Smart City Applications

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    The paper presents new strategies and algorithms for future mobile power infrastructure planning and operational management in smart cities. The efforts have been made to develop a resilient Electric Vehicle (EV) infrastructure for smart city applications. The goal of this work is to maximize the profit of utility and EV owners participating in real-time smart city energy market subjected to numerous techno-economic constraints of the EVs and power distribution system. For effective real-time applications, the knowledge of artificial intelligence and internet of things (IoT) are used in the proposed model. In order to validate the proposed model for smart city applications, IEEE 33-bus radial distribution network is adopted as a small city power network. The simulation results of proposed model are found to be encouraging when it is compared with the case in which conventional strategies are used

    Optimal integration and management of solar generation and battery storage system in distribution systems under uncertain environment

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    The simultaneous placement of solar photovoltaics (SPVs) and battery energy storage systems (BESSs) in distribution systems is a highly complex combinatorial optimization problem. It not only involves siting and sizing but is also embedded with charging and discharging dispatches of BESSs under dynamically varying system states with intermittency of SPVs and operational constraints. This makes the simultaneous allocation a nested problem, where the operational part acts as a constraint for the planning part and adds complexity to the problem. This paper presents a bi-layer optimization strategy to optimally place SPVs and BESSs in the distribution system. A simple and effective operating BESS strategy model is developed to mitigate reverse power flow, enhance load deviation index and absorb variability of load and power generation which are essential features for the faithful exploitation of available renewable energy sources (RESs). In the proposed optimization strategy, the inner layer optimizes the energy management of BESSs for the sizing and siting as suggested by the outer layer. Since the inner layer optimizes each system state separately, the problem search space of GA is significantly reduced. The application results on a benchmark 33-bus test distribution system highlight the importance of the proposed method

    Phase Relations in the Li2O-V2O3-V2O5 System at 700 C: Correlations with Magnetic Defect Concentration in Heavy Fermion LiV2O4

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    The phase relations in the Li2O-V2O3-V2O5 ternary system at 700 C for compositions in equilibrium with LiV2O4 are reported. This study clarified the synthesis conditions under which low and high magnetic defect concentrations can be obtained within the spinel structure of LiV2O4. We confirmed that the LiV2O4 phase can be obtained containing low (0.006 mol%) to high (0.83 mol%) magnetic defect concentrations n{defect} and with consistently high magnetic defect spin S values between 3 and 6.5. The high n{defect} values were obtained in the LiV2O4 phase in equilibrium with V2O3, Li3VO4, or LiVO2 and the low values in the LiV2O4 phase in equilibrium with V3O5. A model is suggested to explain this correlation.Comment: 6 pages, 7 figures; Phys. Rev. B (accepted

    Optimal planning of hybrid energy conversion systems for annual energy cost minimization in Indian residential buildings

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    The increasing interest in renewables has encouraged power system planners to include the concept of hybrid energy systems in modern power industry. Besides, the modern power consumers are becoming more concerned about their energy bills which has led to the concept of hybrid energy management systems (HEMSs) for buildings to monitor, control and optimally manage energy consumptions without any waste. In this study, an optimal planning framework is proposed to determine optimal capacities and sharing of hybrid energy conversion systems (HECS) such as wind turbine, solar photovoltaic, battery energy storage and the utility grid. The objective is to maximize the net present value of the project/system which includes the cost of annual investment, operation and maintenance costs of HEMS expected to have incurred in the planning period. All the costs and parameters are considered in the Indian context, and Genetic Algorithm (GA) is adopted to solve this proposed planning framework. The simulation results obtained are compared with same obtained for conventional houses in India. The comparison shows that the proposed framework effectively reduces the electricity bills while improving its reliability

    Transport and Magnetic Properties of FexVse2 (x = 0 - 0.33)

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    We present our results of the effect of Fe intercalation on the structural, transport and magnetic properties of 1T-VSe2. Intercalation of iron, suppresses the 110K charge density wave (CDW) transition of the 1T-VSe2. For the higher concentration of iron, formation of a new kind of first order transition at 160K takes place, which go on stronger for the 33% Fe intercalation. Thermopower of the FexVSe2 compounds (x = 0 - 0.33), however do not show any anomaly around the transition. The intercalation of Fe does not trigger any magnetism in the weak paramagnetic 1T-VSe2, and Fe is the low spin state of Fe3+.Comment: 7 pages, 8 figures, 2 table

    Multi-objective optimal DG allocation in distribution networks using bat algorithm

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    Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.The Distributed Generations (DGs) storage may store energy during solar energy peak and use it during peak demand. Proper allocation of DG storage is essential to extract maximum possible benefits. This paper introduces a Bat Algorithm (BA) for optimal allocation of DGs in radial distribution networks. The problem is formulated to maximize annual energy loss reduction and to maintain a better node voltage profile under a piece-wise linear variable load pattern using a penalty factor approach. The proposed method is applied on the benchmark IEEE 33-bus and 69-bus system available in literature and the results obtained are promising.dc201

    Locked-in Syndrome in a Young Patient Due to SARS-CoV-2: A Case Report

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    © Copyright © 2020 Sattar, Iqbal, Haider, Zia, Niazi, Hanif, Ali and Khan. Coronavirus disease 2019 (COVID-19), apart from commonly involving the respiratory system, has its impact on the central nervous system, with a wide spectrum of clinical presentations ranging from headaches to ischemic strokes. The ongoing research regarding this novel disease has found that there is a very high prevalence of thrombotic episodes especially in critically ill patients when compared to severe presentation of other viral illnesses. This COVID-19-associated coagulopathy has a very complex etiology with the ability to form thrombus in arteries, veins, and microvasculatures of different organs. We present a unique case of a young woman with underlying COVID-19 who unfortunately developed locked-in syndrome due to bilateral pontine infarction during the course of her illness

    A field indoor air measurement of SARS-CoV-2 in the patient rooms of the largest hospital in Iran

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    The coronavirus disease 2019 (COVID-19) emerged in Wuhan city, China, in late 2019 and has rapidly spread throughout the world. The major route of transmission of SARS-CoV-2 is in contention, with the airborne route a likely transmission pathway for carrying the virus within indoor environments. Until now, there has been no evidence for detection of airborne severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and this may have implication for the potential spread of the COVID-19. We investigated the air of patient rooms with confirmed COVID-19 in the largest hospital in Iran, on March 17, 2020. To collect the SARS-CoV-2 particles, ten air samples were collected into the sterile standard midget impingers containing 20 mL DMEM with 100 μg/mL streptomycin, 100 U/mL penicillin and 1 antifoam reagent for 1 h. Besides, indoor particle number concentrations, CO2, relative humidity and temperature were recorded throughout the sampling duration. Viral RNA was extracted from samples taken from the impingers and Reverse-Transcription PCR (RT-PCR) was applied to confirm the positivity of collected samples based on the virus genome sequence. Fortunately, in this study all air samples which were collected 2 to 5 m from the patients' beds with confirmed COVID-19 were negative. Despite we indicated that all air samples were negative, however, we suggest further in vivo experiments should be conducted using actual patient cough, sneeze and breath aerosols in order to show the possibility of generation of the airborne size carrier aerosols and the viability fraction of the embedded virus in those carrier aerosols. © 2020 Elsevier B.V
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