Applied Mechanics and Materials Vols. 641-642

Abstract: The vertical distribution of aerosol extinction coefficients, and relativity between aerosol and BC the within summer planetary boundary layer (PBL) over the observation site are shown in this paper. The data indicates that the aerosol is almost trapped within PBL and troposphere layer is rather stable and the main composition of aerosol in Beijing is BC. The multi-layer structure of the aerosol distribution is obvious.

Abstract: By means of building up a three-dimension coordinate system in vector space, the coordinate transform used in instantaneous reactive power theory (IRPT) proposed by H. Akagi is deduced and through spatial coordinate transform two equivalent three-dimension coordinate systems are obtained. After rigorous mathematical deduction the transformation factor for above-mentioned three-dimension coordinate systems is achieved, thus the coefficient deduction for IRPT is solved and the zero-sequence quantity expressing three-phase asymmetrical system is directly obtained. By use of the theory of rotating phasor, the basic principle of instantaneous spatial vector detection method based on IRPT is explained. The authors’ analysis is available for understanding and improvement of this harmonic current detection method.

Abstract: With the development of economy, the energy demand is becoming bigger and bigger, the development of wind energy is one of the main ways to solve energy crisis. In terms of energy utilization, high power wind power connected to the grid is currently one of the most effective ways of wind energy utilization. The wind power generation system connected to the grid plays the role of the changing wind energy into mechanical energy by wind turbines, and then converts mechanical energy into electrical energy by a generator. Because CSCF wind turbine works with the gearbox, which is low efficiency, noise and mechanical loss. And it has not been able to meet the needs of the times. Therefore, the direct drive wind power technology capable of tracking the maximal power point of wind power at rated wind speed has become one of the hot spots in the present research. This paper introduces the converter of the direct drive wind power system and analyzes the working principle of the direct driven permanent magnet synchronous wind power system.

Abstract: With the development of economic and technology, global resources crisis and environment issues have become increasingly prominent, all of these lead new challenges to the electric power grid. In the development of future power grid, Smart Grid (SG) represents a new direction of future development. Smart Distribution Grid (SDG) is an important breakthrough in SG as the last part of the power system to the user. Firstly, this paper gives the definition of SDG. Then it introduces the key technologies according to the requirement of SDG. Finally, it is concluded that SDG is the inevitable result of the development.

Abstract: Reliability centered maintenance (RCM) is well known for its widely application in various manufacturing industries, but the study on insulating switches of substation is still blank. In this paper, based on RCM evaluation, fault tree is built according to substation fault data, so as to establish fault assessment model of insulating switches. Corresponding fault and maintenance, RCM evaluation model is set up to assess substation maintenance scheme. After combining with actual data from all substations, a series of calculation is implemented, which lead to improving suggestions. Eventually, optimal reliability and economical efficiency is achieved.

Abstract: With the rapid development of electric power construction , transmission lines and the surrounding geological environment influence each other that has become increasingly serious, however, there is not formed yet a set of complete and more scientific geological environmental evaluation system in transmission lines at present. In this paper, on the basis of using the experience of other industries of geological environmental evaluation research , study and put forward the geological environmental evaluation method specifically for transmission lines. Evaluation system is established for transmission lines in planning period and construction period , and also put forward the corresponding evaluation index. The research conclusion can provides theoretical support and maintenance for transmission lines of the whole life cycle design,and it also provides reference in designing transmission lines plan and preventing, and controlling geological environmental problems of transmission lines for the decision-making department.

Abstract: This article calculate the potential distribution of the line charge and infinite medium cylindrical shell, it is discussed that the electric potential of linear charge and dielectric medium cylinder shell system or the electric potential of linear charge and medium cylinder system and can be given by the line charge and medium cylindrical shell system potential.

Abstract: Currently, the Chinese code calculate the wind loads of transmission towers and lines separately, the code methods make the loads of ground wire which was regarded as external loads force on the transmission tower, without considering the coupling effect between the tower and line, this method does not accord with the actual working state of the transmission tower. Therefore, according to the actual state of tower-tower-line coupling, this article established the finite element model of its system. What’s more, on the basis of different layout of damper system, the dynamic response and vibration reduction effect of the tower-line coupling system under different conditions were studied in this paper. The results show that, both can reduce the system’s vibration effectively while considering the tower-line coupling and with the consideration of different damper layout schemes at the same time. The third scheme which is tower head lower half part edge member bar plus dampers had the most significant vibration reduction effect. The research results can be reference for engineering design and engineering practice, it also has a certain theoretical and practical significance.

Abstract: V2G technology is an important part of the smart grid,which realizes the power inter-transformation between Power Grid and electric vehicles [1]. V2G technology is introduced and the structure of charging and discharging system in V2G technology is analyzed [2]. Under synchronous rotating frame, the combination current-controlled and Voltage space vector control method is adopted, which carries out the power inter-transformation between Power Grid and electric vehicles [3].

Abstract: Harmonics of power system seriously affected the quality of electric power. Shunt Active Power Filter (SAPF) [1] which overcomes the shortcomings of passive filter (PF) has become main technology to suppress harmonic. In this paper, structure, mathematic model, detection method and control of SAPF are mainly analyzed and reviewed. With development of key technology of APF, it will have a better application prospect.