Virtual power plant (VPP) is an effective technology form to aggregate the distributed energy resources (DERs), which include distributed generation (DG), energy storage (ES) and demand response (DR). The establishment of a unified and coordinated control of VPP is an important means to achieve the interconnection of energy internet. Therefore, this paper focuses on the research of VPP construction model. Firstly, a preliminary introduction on all kinds of the DERs is carried out. According to the relevant guidelines, the decision area of the VPP is carefully divided, and the decision variables representing the various resources in the area are determined. Then, in order to get a VPP with low daily average cost, good load characteristics, high degree of DG consumption and high degree of resource aggregation, a multi-objective VPP construction model based on decision area division is established, and various constraints including geographic information are considered. The improved bat algorithm based on priority selection is used to solve this model. Finally, the correctness and effectiveness of the model are verified by an example.

With increased direct current (DC) load density and the penetration of a large number of distributed generation (DG) units in alternating current (AC) distribution networks (DNs); a planning approach that considers transforming some of the AC lines into DC lines and building the DC network is proposed. Considering the DG output uncertainty and the load fluctuation, a planning model for an AC/DC hybrid distribution network (DN) with the DG based on the construction of multi-scenario technology with timing characteristics is built. In the DG configuration planning model, the lines to be transformed into DC form the access location and the decision regarding the DC or AC form of the newly built lines are considered optimizing variables. The DG investment, the network and converters of the DG and load, the active power loss and the voltage stability are considered in the objective functions. An improved adaptive niche genetic algorithm based on the fuzzy degree of membership and variance weighting is used to solve the nested model. Finally, considering the improved electrical and electronic engineers 33 (IEEE33) node system as an example, the correctness and effectiveness of the proposed planning method are verified. Compared to the plan without transforming some of the AC lines into DC lines and building a DC network, more DG can be admitted, and the economic cost of the AC/DC hybrid DN is notably decreased when planning to transform some of the AC lines into DC lines and build a DC network. The active power network loss and the voltage stability index are similarly further optimized.

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In this paper, the antibacterial property of hemp fiber was studied before and after extracted with ethanol. Simultaneously, the chemical composition of ethanol extract from hemp fiber was analyzed and characterized by UR and FT-IR. Experiment results show that, the antibacterial property of hemp fiber decreased after extracted with ethanol. The Inhibitory rate to Candida albicans decreased from85.7% to 64.4%. The Inhibitory rate to Staphylococcus aureus, Escherichia coli and Candida albicans deceased as extraction time prolonging, and attained equilibrium after about 4 hours. Through experiments and date analysis by using FT-IR and UV, hemp fiber contains chalcone. It is initially argued that the active anti-bacterial constituents of hemp fiber may be alkaloids, flavones and saponins.

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