Current Issue : July - September Volume : 2018 Issue Number : 3 Articles : 5 Articles
A new dynamic model is developed in this paper based on the generic MATLAB\nbattery model. The battery capacity is expressed as a function of the self-discharge\nrate, the discharge current, the cycling life and the temperature of the battery.\nThe dependence of the model parameters on cycle life and temperature are estimated\nfrom the first order approximation. The detailed procedures and formula\nto extract the model parameters are presented and the extraction relies\nonly on the discharge curves at two different discharge currents, at two different\nlife cycles, and at two different temperatures. These discharge curves are typically\nprovided in the battery manufacturer�s datasheet. The proposed model is\nverified for both nickel-metal hydride and lithium-ion batteries by comparing\nthe calculated discharge curves with the results from the generic MATLAB\nmodel. The model is further validated for the Sinopoly lithium-ion battery\n(SP-LFP1000AHA) by comparing the model results with the discharge curves\nfrom the manufacturer�s datasheet at different discharge currents, different cycling\nnumbers, and different temperatures. Simulation results show that the new\nmodel can correctly predict voltage separation beyond the nominal zone while\nmaintaining the same level of accuracy as the generic MATLAB model in the\nexponential and nominal zones....
This paper proposed a study on the power dispatching optimization in the microgrid aiming at Chinese national condition based\non PSO algorithm. The whole work is on the basis of the weighted factor variation of the objective function due to different weather\nconditions.Three cases including the good contamination-diffusingweather condition, the smogweather condition, and the normal\ncondition are considered, respectively. In the case of smog weather, the new energy generation and the battery system will be all\nout to use as less power as possible from the primary grid so that the pollution produced by coal consumption in the thermal\npower plants can be upmost reduced. However, in the case of perfect contamination-diffusing weather, the battery is not used to\nreserve its lifetime, while a large amount of exchanged power from the primary grid is used to obtain a most economic-efficient\neffect. In normal condition, the power dispatching is performed in a most balanced way considering not only the cost but also the\nenvironmental management. The case study in Suzhou Industrial Part confirms the effectiveness of the proposed method in this\npaper....
A solar chimney PV/T power plant (SCPVTPP) is proposed. Mathematical models are established for the PV/T solar collector,\nthe chimney, and the power conversion unit, respectively. Performances of the designed SCPVTPP are then simulated. The\nSCPVTPPs with different PV module areas are finally discussed. It is found that the PV cells hold the highest temperature in\nthe solar collector. Temperature rise of the PV module has significant influences to its power generation. Without cooling, the\nPV power capacity has an average decrease of 28.71%. The contradictory influences of temperature rise and airflow cooling\nlead to an 11.81% decrease of the average power capacity. By adding the power generated by PVT, the total PV-related power\ncontribution increases by 4.72%. With the increase of the solar collector ratio, the temperature rise and the wind velocity both\nfirst decrease then increase, the SCPP power productivity decreases linearly, and the PV power productivity increases linearly,\nwhereas the PVT power productivity first increases linearly then increases superlinearly. There is a reversed solar collector\nratio, exceeding which the PV generates most power. In this study, solar thermal power takes the major role when the solar\nPV area ratio is smaller than 0.055....
The installation capacity of wind and solar photovoltaic power is continually increasing, which makes renewable energy grid\nconnection and power generation an important link of China�s power structure optimization. A virtual power plant (VPP) is an\nimportant way to help distributed energy resource grid connection and promote renewable energy industry development. To study\nthe economic scheduling problem of various distributed energy resources and the profit distribution problem of VPP alliance, this\nstudy builds a separate operation schedulingmodel for individual VPP and a joint operation schedulingmodel for VPP alliance, as\nwell as the profit distribution model. The case study verifies the feasibility and effectiveness of the proposed model. The sensitivity\nanalysis provides information about VPP decision-making in accordance with the policy environment development trend....
The paper dwells on the unified power quality indexes characterizing the\nphenomenon of voltage unbalance in three-phase systems. Voltage unbalance\nis one of the commonest occurrences in the town mains of 0.38 kV voltage.\nThe phenomenon describes as inequality of vector magnitude of phase voltage\nand shearing angle between them. Causes and consequences of the voltage\nunbalance in distribution networks have been considered. The algorithm,\nwhich allows switching one-phase load, has been developed as one of the methods\nof reducing the unbalance level. The algorithm is written in the function\nblock diagram programming language. For determining the duration and\nmagnitude of the unbalance level it is proposed to introduce the forecasting\nalgorithm. The necessary data for forecasting are accumulated in the course of\nthe algorithm based on the Function Block Diagram. The algorithm example\nis given for transforming substation of the urban electrical power supply system.\nThe results of the economic efficiency assessment of the algorithm implementation\nare shown in conclusion. The use of automatic switching of the\none-phase load for explored substation allows reducing energy losses (active\nelectric energy by 7.63%; reactive energy by 8.37%). It also allows improving\nsupply quality to a consumer. For explored substation the average zero-\nsequence unbalance factor has dropped from 3.59% to 2.13%, and the negative-\nsequence unbalance factor has dropped from 0.61% to 0.36%....
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