Applied Mechanics and Materials Vol. 681

Abstract: Electrical safety is a common goal of electricity customers and power companies. In order to meet the needs of different users for electricity safety, ensure the legitimate rights and interests of the State Grid Corporation and users, promote the service level of State Grid Corporation and improve the life quality of the users, an effective measures is the user electricity safety inspections. Firstly, it introduces the development of cloud computing technology and the advantages of the user electricity safety monitoring system based on cloud computing technology. Secondly, from three aspects of the system structure, function and cloud system, the user electrical safety monitoring system based on cloud computing technology has been elaborated. Lastly, it discusses the development of the lateral user electricity safety monitoring, and provides the reference for the application of user electricity safety inspections.

Abstract: Transformer is one of the most important equipment in power system, and accurate condition assessment for transformer is the key for condition based maintenance (CBM). So the study of condition assessment is particularly important. In this paper, the function, role and steps of condition assessment, research status, existing problems and future directions are analyzed and summarized. And this paper can be a reference for transformer’s condition assessment.

Abstract: There is not a component which can implement the algorithm of space vector pulse width modulation (SVPWM) in the PSCAD/EMTDC. The principle of SVPWM is explained firstly. Then the creating process of the self-defined component and the program flowchart of SVPWM are presented. The algorithms of the subroutine are also discussed in detail. Finally, the simulation is performed by using the self-defined component in the system. Simulation results demonstrate the correctness and validity of the inverter and self-defined component.

Abstract: Large disturbance stability of the system was greatly affected by the way of a lot of wind power centralized access to high voltage transmission network. We could use the traditional operation control scheme of controlling the wind farm and the nearby generator system operation output, but the wind farm and conventional power plant's interests would be seriously affected. Therefore, this paper put forward the control strategy by using the combination of low voltage protection and security automatic device. Large disturbance stability level could reach or close to the level before the wind, so as to minimize the impact of wind power integration on large disturbance stability of power system.

Abstract: The Cu₂O addition deteriorates the electrical properties of ZnO varistors, which is a good agreement with similar findings on Ag₂O additions. The best fitted impedance analysis reveals that the Cu₂O addition increases grain resistance and lowers the grain boundary resistance, results in low nonlinearity and higher leakage current of ZnO varistors.

Abstract: In order to study deeply the cause of mal-operation of the current increment protection and then redo the setting calculation, the all-parallel AT traction network model and the simulation model of Electric Multiple Units (EMU) are established. Using the model that has been established and Simulink simulation tool, the situation while the EMU is being started, passing neutral section or the traction network has grounding fault with interruption was simulated. The simulation result show that the current increment when the EMU starting is significantly different from that situation when fault occurring. While the situation when the EMU passing neutral section is the opposite. So we can draw a conclusion that the current increment protection will not appear mal-operation when the EMU starting and when passing neutral section may appear mal-operation. Finally, the current increment protection setting principle has been improved, and its feasibility has been verified.

Abstract: Few studies have been conducted on the constructability or economic feasibility of the coupling of Pre-tensioned Spun High Strength Concrete (hereinafter PHC pile). For this reason, before applying it to actual construction sites, an analysis of constructability and economic feasibility is necessary. Therefore, this study aims to compare the welding method with the high-tension vertical bolt method. It is found that the use of the high-tension vertical bolt method can reduce expenses by 25 percent on average compared with the welding method.

Abstract: Abstract. With the development of building science and technology, there are more and more super high-rise buildings. Meanwhile, difficulties in structural design and construction are also on the rise. As the finite element technology field develops, there are numerous types of structural design software, with different mutual functional characteristics. In order to satisfy the design and construction calculation of large-scale engineering, formats of different structural models shall be converted frequently, so as to satisfy the demand of design and construction calculation. In this paper, a simple method will be sought for converting the finite element model of SAP2000 structural design into ANSYS finite element model based on super high-rise structural design model by combining the practical engineering. After conversion, simple APDL ^[1] programming can be applied for realizing the conversion technology of model.

Abstract: Rollers are widely used in the construction of infrastructure; the influence of vibratory on surrounding environment caused by roller in construction is increasingly prominent. In order to solve this problem, a monitoring experiment was conducted in a compacted subgrade construction site to show how the vibratory of roller impact on surrounding environmental. Through the analysis of compacted subgrade monitoring data show that the peak fast decline rapidly with distance attenuation, the prediction formula is: a = 1657.85 * R ^ (-1.1), Based on the impact of compacted subgrade vibration velocity, frequency, and duration on the surrounding buildings is analyzed and found that the vibration velocity and frequency are less impact on the housing, but the duration of the construction will have an impact. Lastly, from Z vibration level and seismic intensity angle, the effects of vibration on personal feelings and building structures caused by vibration acceleration is analyzed. Furthermore, the way of excavating vibration attenuation ditch to control effect of vibration is proposed to the greatest impact of vibration on the residential buildings.

Abstract: The main structure of wind tunnel is special-shaped thin-walled structure. During the design and construction phase, its static strength, static stiffness and dynamic characteristics have to be taken into account. The author explains the meshing method of the main structure of wind tunnel in which finite element computing model is established through ABAQUS according to model simplification principle and analysis of stress, deformation and modality is done on this wind tunnel model. Analysis results show that the main structure of this wind tunnel caters for requirements of static strength and static stiffness in which overall stiffness distributes reasonably, modal frequency presents good distribution and condition permits to do further optimization on part of components. Straight section wall of wind tunnel affords the most pressures while dip angle section amplifies or reduces according to cross section of downwind section. Amplification section is suction-based and wall of amplification section is pressure-based. This analysis result would provide references for tension analysis of roof surface.