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Research On The Hybrid Control Strategy Between Controllable Load And Energy Storage System In Microgrid

Posted on:2017-09-23Degree:MasterType:Thesis
Country:ChinaCandidate:J W YinFull Text:PDF
GTID:2322330491462466Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
Microgrid is a small distribution system which is composed of distributed generations, energy storage systems, loads, monitoring and protection devices. As an effiective form for renewable energy access to the large power grid, microgrid has attracted more and more attentions. Both controllable load (CL) and energy storage system (ESS) are the important parts of microgrid, the optimization and control of them can effectively enhance the operation ability and benefit of microgrid. However, the research on coordination control between them is not thorough enough, and the controllable resource has not been fully utilized. Based on the background, CL and ESS are the main research objectives in this paper, and the focus is the problem of coordination control between them. The main content of this paper can be listed as follows:(1) Considering the background that global energy crisis and environment problem is increasing serious and the rapid development of distributed generation, the development status of microgrid in U.S., Japan, EU and China is introduced in detail. The research on CL, ESS and the coordination between them has been overviewed systematically.(2) The framework of hybrid control strategy between CL and ESS is proposed. It includes the local control layer, distributed coordination control layer and centralized optimal scheduling layer, which are corresponding to the integrated control strategy between CL and ESS, the distributed control strategy based on consensus algorithm and the centralized energy management strategy considering CL classification and ESS life.(3) An integrated control strategy between CL and ESS is proposed, which takes the characteristic that CL has large controllable capacity, low control cost and the power of ESS can be adjusted preciously into consideration, the Load-Storage Integrated Unit (LSU) is designed. When microgrid is in grid-connected state, the optimization objective of LSU is the minimum adjustment cost. While in islanded state, the objective of LSU is the minimum influence range and the fastest response rapid. At last, the control strategy has been verified through simulation and laboratory test.(4) A distributed control strategy based on consensus algorithm is proposed, which is concentrated on the economic dispatch problem (EDP) between ESSs. The EDP is analyzed in detail and the characteristic is used to desigen a solving method based on algorithm. At the same time, the state of charge (SOC) and state of health (SOH) are considered when building the economic model of ESS, which can lead to a more reasonable and accurate result of EDP. The strategy is verified through numerical simulation in grid-connected state and islanded state. The incluence of economic model of ESS has also been anylized at the same time. In addition, the strategy has shown its good adaptability in large scale system.(5) A centralized energy management strategy is proposed, which considers CL classification and ESS life. The load is classified based on its controllable ability, including uncontrollable load, translational load and cuttable load, and the CL model is built. When building the economic model of ESS, the influence on the attenuation of capacity result from the charge power and discharge power is considered. Based on the above models of CL and ESS, with the optimization objective of minimum cost of daily electricity, the electricity plan is designed. At last, taking a household microgrid as the research object, the strategy is verified through numerical simulation.
Keywords/Search Tags:Microgrid, Controllable load, Energy storage system, Energy management, Hierarchical coordination control, Power optimization and dispatch
PDF Full Text Request
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