Advanced Materials Research Vols. 791-793

Abstract: The mechanism of over-voltage is analyzed according to the problems that insulated equipment is breakdown and threat to traffic safety when locomotive goes through overlapping electrical sectioning device which generate over-voltage. The model of overlapping electrical sectioning device is established by using PSCAD software. By comparing the size of overvoltage when locomotive goes through seven and eight-span overlapping electrical sectioning device, and RC protection devices is installed in seven-span overlapping electrical sectioning device .It can be introduced : inhibitory effect is significant by installing RC protection devices in the neutral line for over-voltage . Inhibitory effect will be more obvious by installing RC protection devices in the neutral line for over-voltage compared to seven-span overlapping electrical sectioning device.

Abstract: This paper discusses a lithium battery-driven cold plasma jet at atmospheric pressure with a pulsed power supply of design and its simulation. H.V. DC(High voltage directed current) and pulsed discharge circuit comprise of the entire pulse power system. H.V. DC circuit using TIs TMS320F28335 chips as the core of the circuit control module, the chip improves the stability of the H.V.DC circuits. Pulsed discharge circuit design plays a crucial impact on the formation of the narrowed pulses. A new double pulsed discharge circuit is designed by the proposed program. As discharge experiment shown finally, the steep narrowed pulse of pulsed power supply can be used to stabilize the output of the pulsed front.

Abstract: With the realization of physical memristors, using memristors to perform stateful logic operations has been demonstrated feasible. In such operations, memristors simultaneously serve as latches and logic gates, thus enabling the in-situ computing which may open a new computing paradigm for computer architecture. In this paper, we first analyze two types of typical memristive stateful logic gates to reveal the working mechanism of the stateful logic, and then review the recent researches on the memristive stateful logic, and finally discuss the pros and cons of the stateful logic. We reach the conclusion that the stateful logic promises a novel computing paradigm which may revolutionize the conventional computer architecture, while its development is currently subjected to the state drift problem and is constrained by the lack of a general design methodology and physically verification.

Abstract: There are often some problems during operation of the resonant grounding grid, such as tracking failure, excessive tuning, and oversize residual current caused by compensation not matching grounding fault. A new idea is proposed to solve the problems about using of the neutral voltage detection, analysis and calculation. Firstly, neutral voltage characteristics are analyzed. Secondly, neutral voltage is applied to the calculation of tracking sensitivity, and the problems of tracking failure and excessive tuning are effectively solved. Thirdly, change of operation mode and grid disturbance are distinguished by using characteristics of neutral voltage variation. Lastly, the formulas of neutral voltage ranges are derived, which can distinguish high-resistance grounding fault from low-resistance grounding fault and achieve a smart compensation. This solves the problem of excessive residual current. Simulations verified the above conclusions and the results are satisfied.

Abstract: The contradiction between the unbalanced geographical distribution and the electricity consumption of energy distribution determines the long-distance; high-capacity transmission will be an important feature in the future development of the electric power industry. Based on GPS technology, WAN synchronized phases measurement technology has provide real-time dynamic information to the system. However, continuous improvement of the PMU distribution and the real-time monitoring of the grid by WAMS system increasingly comprehensive, massive measurement data have been brought about. Studying the measured data from various trips; it meets the 3V (volume, variety, velocity) characteristics of big data. This paper presents big massive data processing methods to solve the problem with various angles, and its feasibility and necessity.

Abstract: With the constant expansion of the power system and the popularity of WAMS system, to analyze the stability of power system based on WAMS data has become a hotspot studied at present. This paper researches the methods to rapidly extract the critical electrical characters of the power system in fault condition. Principal component analysis is used to extract transient characters of power system, and the results are used in the transient stability assessment, proving the effectiveness of this method.

Abstract: Magneto-elastic cable tension sensor have a number of advantages, it will be ideal method to measure cable tension in large span cable-bridge, but the sensor is sensitive to temperature, so the temperature influence is not negligible to sensor. In this paper, the principle of cable tension sensor based on magnetic-elastic effect is introduced, the common temperature compensation technique are detail analyzed. A novel method of temperature compensation by adjusting the bias magnetic field is put forward, by theoretical analysis and experiment, indicated that it is feasible to compensated the temperature influence.

Abstract: Designers are increasingly relying on FPGA-based emulation to evaluate the performance of LDPC codes. In this paper, we propose a novel approximate lower triangular structure for the parity part of the parity-check matrix of QC-LDPC codes. Next, a high speed partially parallel decoder architecture which based on the Offset BP-based decoding algorithm is proposed. The results indicate that the frequency can reach 100MHz and its throughput rate can reach 113Mbps.

Abstract: Analyzed the unique characteristics of reading and writing the flash memory, and researched the ways of designing a file system. The target embedded file system has the advantages of the traditional file system and the sequential file system. It is able to adapt to the unique characteristics of reading and writing the flash memory. It can solve the inconsistent data problem in the embedded device when power down. And it can solve the bad blocks of the flash which are generated by erase operations also.

Abstract: Distributed resources and microgrids may be designed for power supply in some area. AC-DC or DC-AC conversions are required in microgrids because of DC distributed resources, e.g. photovoltaic arrays. In this paper some factors are considered for determining the voltage grades of microgrids, both AC grid and DC grid, according to comprehensive analysis of microgrid design and operation. The factors include microgrid or distributed resource capacity, efficiency, cost, safety and so on. The line length, microgrid capacity and economic impacts are taken into account for selecting the voltage grade to connect the microgrid into the distribution system. Further, suitable AC and DC voltage grades are selected for residential and commercial application with some microgrid cases.