Applied Mechanics and Materials Vols. 687-691

Abstract: When the Optical Current Transformer (OCT) with different sampling frequencies is applied to differential protection, the output data of OCT of each branch of the differential protection are required to be converted to a uniform sampling frequency. The filtering algorithm is inevitably applied in the progress of frequency conversion. In the essay, a new Zero Phase Maxflat filtering algorithm, the prototype of which is IIR digital filter, achieving zero phase maxflat pass band amplitude characteristics and zero-phase filtering. The algorithm is with high accuracy and achieves a rapid filter with lower order along with the shorter filter time and fast protection action. In the end, simulation is used to verify the feasibility and effectiveness of the algorithm.

Abstract: It has been well recognized that the methods for electrical load modeling have significant impacts on the power systems operation, simulation, analysis and security assessment. Compared with the power grid of infinite capacity, the equipment power system with a large number of power electronic devices has larger internal resistance, and the application objects of the model face to the three-phase four-wire independent power supply system. Therefore, this paper deals with the problem of the three-phase four-wire harmonic load modeling in the equipment power system of infinite capacity, including the basic idea and principle of nonlinear load design, the main circuit structure of the chosen four-leg PWM converter, and the overall control strategy. Based on FFT analysis comparison between the real measured data and the simulation data, it is further shown that the load model can reproduce accurately the current waveform distortion, and simulate the harmonic characteristics of the steady state and transient state of equipment power system.

Abstract: Recently, solar LED lighting systems are widely used because of their energy-saving and environment friendly characteristics. But there are also some key problems in current solar LED lighting systems, such as follows: First, the lifetime of lead-acid battery is too short so that the whole system lose efficacy soon; Second, current solar LED lighting systems usually are isolated systems, so its controllability is worse. This paper propose a new solar LED intelligent lighting systems based on Internet of Things and Supercapacitor ,which can tackle these two problems better, so the solar LED intelligent lighting systems will advance applications of solar LED lighting systems.

Abstract: A capacitor memory erasing technique for pipeline ADC is introduced, which insert a clearing phase to the traditional working timing sequence of the MDAC to erasing the residual charges on the sampling capacitor. The measurement shows that the 14-bit pipeline ADC adopting the proposed technique can achieve a sampling rate of 250MSPS with SNR 69dB, SFDR 80dB, compared with the traditional ADC of sampling rate 100MSPS, SNR 60dB, SFDR 71dB, which proves the proposed technique can improve the performances of pipeline ADCS obviously.

Abstract: Large consumers, one of the most important groups which power supply company serves, are nowadays producing increasingly prominent operational risks. The urgent problem that power supply companies face, is to scientifically, accurately and immediately control the risks and its impacts. This paper mainly forces on the visualization of large consumers’ operation risk information in the power supply company. First, the characteristics of operational risk information are analyzed from different dimension features, and various visual elements which are applicable to different risk factors are summarized. On the basis of the first step, combined with the diversified characteristics of large consumers’ risk information, two modified risk visual elements, Heatmap and Treemap, are designed. Finally, the visualization schemes of large consumers’ operational risk information are proposed by instance. Results show that administrators can timely discover and recognize large consumers’ operational risks from these schemes, which effectively improved risk visualization and early warning capabilities.

Abstract: One of the main reasons caused the blackout accident is the existence of the power grid vulnerable unit. Therefore, how to find out the existing vulnerable unit accurately becomes a hot topic in the power grid at present. In this article, the problem aiming at the insufficient of grid vulnerability metrics is studied. Firstly, the new comprehensive vulnerability indicator was constructed to remedy the disadvantages of the current indicators of grid vulnerability. Secondly, the calculation process was listed. Finally, the advantages and disadvantages of the new indicator and the traditional indicator were analyzed in detail in the IEEE typical example. The result of the example shows that the new indicator built in this article is valid.

Abstract: For hardware Trojan detection process is difficult to effectively extract the exact equivalent logic function of the target chip logic function is proposed based on contradictory truth table equivalent extraction scheme and key Enabling technologies. Designed to target chip waveforms attribute recognition model, through the analysis of multiple properties of the model and proof, the work is given waveform attribute recognition model parameter setting principles.

Abstract: This paper set up two structures model of switched-capacitor circuit based on second-order output settling, one type is charge transfer, the other is capacitance overturn. According to charge conservation when in charge storage and charge transfer process, the transfer function derived. By analyzing the time-domain solution in the form of output function, we find out the factors which influence on the rate of SC. In order to achieve the fastest settling time, the phase margin of open-loop amplifier is 63.4° in charge transfer by calculated, while in capacitance overturn is 76°.

Abstract: The paper realized a smart home system based on FS_S5PC100 hardware platform and Android frame, and finished the JNI procedures, the Linux bottom drivers and the user interface based on Java. It provides the good theoretic references for develop the real relevant smart home systems in the future.

Abstract: The temperature of transmission line is an important parameter in the condition monitoring system on transmission line and its measured value is affected by the state of sensors. General regression neural network (GRNN) was used to construct an auto-detection network for temperature sensors of transmission line. Optimizing design of network, error controlling and effect testing were studied, and also a method of threshold for sensor detection was advanced. The network is verified by practical data from a 220kv transmission line in Sichuan Province and is proved to be with good value of engineering application for sensor state detection of unit.