Applied Mechanics and Materials Vols. 651-653

Abstract: In order to improve the diagnosis rate of wavelet neural network algorithm for the radar circuit, for the network during operation there is poor convergence, the training error and shortcomings easy to fall into local minimum, the network is unable to continue training and testing, proposing a new algorithm of increasing the momentum of the wavelet adaptive neural network, can make the network run more stable, faster learning rate; By the Matlab simulation experiments show that the diagnosis rate of the improved algorithm is much higher than the ordinary one.

Abstract: Because of the high spending and better smoothing affect of VRB, studying the wind power compensation ratio of VRB system become more and more important. The paper proposes a new way to get the power compensation ratio of VRB system, through analyzing the transient stability influence on wind speed fluctuation. Make use of PSASP for transient stability analyzing and observe the smooth affect of the wind disturbance based on the model of IEEE-14. The performance of the proposed method has been evaluated with the comparison of transient stability analyze, the comparison demonstrates the wind power compensation ratio of VRB system.

Abstract: EMTDC is grid simulation analysis software that is capable of modeling for complex electrical and electronic devices, controllers and non-linear network. PSCAD is a user graphical interface of EMTDC. In PSCAD environment, functional modules can be taken from the element library conveniently to set up a complete set of LV SVG control system for simulation study of operation performances under various work conditions. However, the control program of LV SVG in actual application is written in C language, which has great differences from some functional modules in PSCAD simulation module in terms of data processing approach and calculation precision, so there is a huge gap from the simulation result and the actual result.In this paper, Fortran language is used to write interface function. Control program written in C language is embedded into the simulation module set up by EMTDC. An experiment shows that the simulation model built by EMTDC and C language mixed programming has higher precision than ordinary simulation module, and can be transplanted among LV SVG controllers, so it’s more practical.

Abstract: Power user electric energy data acquire system is the important part of building a strong smart grid, and the communication system building is placed in the key position. Firstly, the application of wireless communication technology in the electric energy data acquire system is introduced in this paper. Secondly, the EPON technology is given. Lastly, a comparison of the two communication schemes is made in the ten aspects in detail, hoping that it is as a reference for the construction of power user electric energy data acquire system.

Abstract: Li-ion battery, with the advantage as small size, large power density, high individual voltage, low self-discharge rate, and low internal resistor so on, substitutes the traditional power battery used in AGV system. In the practical application, Li-ion battery discharge with large current after a period of time, the upper voltage of every cell will be non-consistency, and the power system will work abnormally. In the case, the intelligent management of li-ion battery is designed.Experiment result improves that the system can effectively protect the li-ion battery and realize the energy feedback.

Abstract: This design uses the pyroelectric infrared detection technology, single-chip microcomputer control. Pyroelectric infrared sensor sensing the infrared thermal radiation (the body temperature is 37 degrees) of the invaders, converting it into a low frequency signal, passing to microcontroller through amplified circuit. Finally, it implements anti-theft through the alarm module.

Abstract: In order to control the micro harmonic, maintain the micro-grid power balance, make it operate more safe, reliable, using the micro grid energy storage system and the active power filter in combination is put forward, so as to achieve the improvement of micro grid power quality, improve the utilization rate of energy storage devices and save the investment cost. The method is to simulated by the MATLAB to verify the feasibility.

Abstract: In order to check whether there are defects in GIS (gas-insulation-switchgear), it is necessary to do AC voltage withstand test before putting into operation. According to the standards, when doing AC voltage withstand test after GIS expansion or maintenance, the original neighboring parts should be power cut and grounded. For the double bus substation,it means that the whole substation should be power cut, which will decrease the power supply reliability of the grid and have a tremendous impact on the power grid To solve the problem, this paper presents a new AC voltage withstand test method for GIS without power cut, and explains principles and field applications of this method.

Abstract: Wind speed forecasting plays a significant role to the operation of wind power plants and power systems. An accurate forecasting on wind power can effectively relieve or avoid the negative impact of wind power plants on power systems and enhance the competition of wind power plants in electric power market. Based on a fuzzy neural network (FNN), a method of wind speed forecasting is presented in this paper. By mining historical data as the learning stylebook, the fuzzy neural network (FNN) forecasts the wind speed. The simulation results show that this method can improve the accuracy of wind speed forecasting effectively.

Abstract: Not only the construction industry as a pillar industry of the national economy, it is a major contributor to the regional economy. Identification of competitive strengths and weaknesses of the Yunnan Province in the western region, the article is based on the improved TOPSIS to analyze. A variety of factors can have an effect on regional construction industry. By combining researches of other scholars and considering of the meaning of construction industry indicator and possibility of data acquisition and analyzing the statistic data of recent three years, is built an evaluation system which contains 5 elements. By some higher mathematics solving method calculates the weight in approach of ranking and comparing competitiveness of the 12 provinces in western region such as Yunnan, Sichuan and Chongqing identifies the regional competitiveness. The consequence shows that the construction industry competitiveness of Yunnan province is at mid-low level among 12 western provinces, but enjoys a good development potential.