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Research On Microgrid Hierarchical Energy Optimal Management Strategy Based On Renewable Energy Sources Forecasting

Posted on:2016-03-01Degree:MasterType:Thesis
Country:ChinaCandidate:Y P JiFull Text:PDF
GTID:2272330479950500Subject:Navigation, guidance and control
Abstract/Summary:PDF Full Text Request
At present, under the double pressure of energy demand and environmental protection, the research on field of distributed generation techniques, which can improve the utilization efficiency of traditional energy and can make use of renewable energy, have been paid for attention gradually in worldwide. Distributed generators(DGs), when clustered to form Microgrid, can bring potential benefit to the users such as improved supply reliability, quality, and better optimization of resources. The energy management system(EMS) of Microgrid is very important for the Microgrid in improving power supply reliability and economical operation.The energy management system of Microgrid can be achieved by centralized or decentralized techniques. However, both types of techniques have their drawbacks and advantages. In this paper, in order to void drawbacks and make best use of the advantages, a two level hierarchical energy optimization and management strategy is proposed based on weak communication between central control and lower level DGs. The main task of central control is responsible for next one hour power assignment based on the output power of DGs and load demand in Microgrid for the purpose of maximum economic and environment benefits. Due to the high-penetration of intermittent energy and the fluctuation of load, the successful power assignment plan is difficult to draw up. The hybrid probabilistic forecast approach, which combines the ensemble empirical mode decomposition(EEMD) and the sparse Bayesian learning(SBL), is developed to improve prediction accuracy. In addition, the upper level EMS can handle uncertainty related to the forecasted errors and improve the Microgrid optimization operation robustness. In order to weaken the dependence on the performance of central controller and communication, the real time active power supply-demand matching of Microgrid completely depends on lower level distributed EMS. The supply-demand imbalance of active power will cause grid frequency fluctuation. According to the DGs characteristic of response time and cost, a two-layer real time active power control strategy is proposed. The energy storage systems only handle the large error of supply-demand imbalance for maintaining the frequency in permissible range; whereas the dispatchable DGs act on secondary frequency control based on optimal distributed algorithm to achieve supply-demand and regulate the power outputs of the energy storages to zero. The validity of the proposed two level hierarchical energy optimization and management strategy is demonstrated by means of simulation results.
Keywords/Search Tags:Microgrid, hierarchical EMS, hybrid probabilistic forecast, cooperative frequency control, weak communication
PDF Full Text Request
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