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Distributed energy storage system (DESS) becomes more and more popular in the distribution network, especially in the era with largely increased the renewable energies. This paper proposed the day-ahead coordinated operation method of active distribution network considering distributed energy storage system integration and network reconfiguration. The objective is to minimize the energy loss of distribution network within one day. The DESS optimal operation model is proposed. The network reconfiguration considered in this paper is a multiple time segment reconfiguration. The purpose is to find a topology structure which can adapt to the load and DG variety within 24 hours. The proposed model and algorithm is verified with a TPC 84-bus system, the different switch operation times and different substation voltages are discussed. The results show the adaptability of the proposed methodology and the necessity to include the DESS and network reconfiguration in the coordinated operation.

Composite material which is light weight, corrosion resistance, high strength, and high insulation, can be used as an ideal material in transmission tower, but lack of corresponding theoretical and experimental research. To research the stability of composite tubes, compression test is applied to total 72 pieces D-type composite tubes. The actual bearing capacity is obtained by experiment, Based on the theoretical, the compression stability calculated formula which is fit for composite tube is proposed, and the formula is modified by experimental data, the experimental process analysis using finite element method is done. The result shows that, the theoretical results calculated by the modified formula proposed in this paper, are relatively similar with finite element method results, and tested values. The result also suggest that the slenderness ratio of the composite tube does not exceed 80 in transmission tower.

The steel tower applying large size angel steel which limb width exceeds 200mm is characterized with good integrity of material, clear force transmission, simple node structure, saving bolts and filling plate, convenient assembly and erection etc advantages. Technical and economic advantage of Q420 large size angle steel tower has been validated in ±800kv ultra-high DC Jinping-Sunan power transmission line engineering. It has been become a tendency to use Q420 large size angle steel to substitute angle steel tower with large design carrying capacity of common combined specification (limb width is 200mm and below). This paper makes thorough analysis and summary on application condition, application characteristic, technology and economy of application, design and research of application, application principle etc of Q420 large size angle steel.