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IEEE Symposium Power Modulator

作者： Ling Dai Fuchang Lin Xiangyu Shi Xingchen Yao Yaohong Cheng Zhiwei Li Cheng Su State Key laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan Hebei China

This paper devotes itself to the experimental study on surface flashover characteristics of insulating material, which is closely connected to the compact pulsed power system operating in vacuum. The rated voltage of the pulsed power source is several kV and the peak current is several kA. To simulate the actual operating condition and possible failure mode of pulsed power system, a series of experiments are performed to validate the adaptability of high pulsed power device in vacuum. This paper concentrates on the mechanism of surface flashover in vacuum and corresponding influence factors. Different metal electrode materials, different creepage distances and the interference effect of hot plasma have been studied. Research indicates that external plasma plays a key role in the formation of surface flashover. In medium vacuum (1×10 -3 Pa), the surface flashover voltage of 3mm surface creeping distance on organic glass is above 17 kV; But if there is external plasma source, the flashover voltage would reduce significantly with the increase of plasma density; flashover voltage would rush to 1 kV or lower. Based on the experiment study, some measures are taken on the several kilovolts pulsed power source (PPS) produced in prior work. The device can operate stably in the vacuum of 10 -3 Pa.

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Communication modeling for wide-area relay protection based on IEC 61850

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Telkomnika - Indonesian Journal of Electrical engineering 2012年第7期10卷 1673-1684页

作者： Chen, Guoyan Yin, Xianggen Zhang, Kai The State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan 430074 China

Wide-area communication system is supporting platform for wide-area relay protection (WARP) exchanging information, which includes not only visible physical communication equipment and links, but also communication protocols and other upper communication services. WARP communication has become an important issue in WARP practical applications, but it has not been described in IEC 61850 standard. To solve this issue, this paper firstly presents the general steps of WARP modeling according to the layer upon layer modeling methods of IEC 61850 standard, then proposes a tree structure model of master station and affiliate stations with information interaction model between master station and affiliate stations following IEC 61850 by taking a 220kV smart substation and WARP algorithm based on fault voltage distribution for example, finally establishes a communication model of WARP that includes client/server transfer model, electrical value transmission model and logical status variables transmission model. The fundamental purpose of constructing the communication model is to implement the interoperability between WARP-IED (WARP-Intelligent Electronic Devices) and other IEDs in a smart substation. © 2012 Universitas Ahmad Dahlan.

关键词： Trees (mathematics)

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A novel fault phase selector for double-circuit transmission lines

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Telkomnika - Indonesian Journal of Electrical engineering 2012年第7期10卷 1730-1738页

作者： Deng, Xing Yin, Xianggen Zhang, Zhe Kong, Xiangping Qiu, Cheng The State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan 430074 China

A novel fault phase selector for double-circuit transmission lines is presented. The fault type is determined with the superimposed components and steady state components of fault voltage. According to the determined fault type, auxiliary criteria based on the magnitude and phase difference of fault phase current is applied to judge whether inter-line fault happens or not. If inter-line fault happens, the fault phase is determined by comprehensive criteria based on the comparison of current magnitude and the judgment of impedance direction. The simulation results verify the correction of the proposed phase selector. © 2012 Universitas Ahmad Dahlan.

关键词： Electric lines

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Architecture and fault identification of wide-area protection system

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Telkomnika - Indonesian Journal of Electrical engineering 2012年第3期10卷 442-450页

作者： Li, Zhenxing Yin, Xianggen Zhang, Zhe Wang, Yuxue The State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan 430074 China

Wide-area protection system (WAPS) is widely studied for the purpose of improving the performance of conventional backup protection. In this paper, the system architecture of WAPS is proposed and its key technologies are discussed in view of engineering projects. So a mixed structurecentralized-distributed structure which is more suitable for WAPS in limited power grid region, is obtained based on the advantages of the centralized structure and distributed structure. Furthermore, regional distance protection algorithm was taken as an example to illustrate the functions of the constituent units. Faulted components can be detected based on multi-source imformation fuse in the algorithm. And the algorithm cannot only improved the selectivity, the rapidity, and the reliability of relaying protection but also has high fault tolerant capability. A simulation of 220 kV grid systems in Easter Hubei province showed the effectiveness of the wide-area protection system presented by this paper. © 2012 Universitas Ahmad Dahlan.

关键词： Computer architecture

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A 60,000-A DC comparator based on dual-loop control system

A 60,000-A DC comparator based on dual-loop control system

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Conference on Precision electromagnetic Measurements (CPEM)

作者： Shiyan Ren Donghui Cai Yumeng Zhang State Key Laboratory of Advanced Electromagnetic Engineering and Technology College of Electrical and Electric Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781467304399

A 60,000-A dc comparator based on dual-loop control system with self-calibration and mutual-calibration is developed. The dual-loop control principle, which is that the bias winding's current automatically balances more than 90% of the dc magnetic potential of the measured current and the feedback winding's current automatically compensates the rest of the dc magnetic potential, is applied in this comparator. The quadruple electricity and magnetic shielding structure is used to get a high precision, which can reach 5×10 -6 accuracy. It has been verified by experiments. Finally, the advantages and bright application prospects are shown in detail.

关键词： Windings Magnetic shielding Magnetic noise Current measurement Control systems Electric potential Standards

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The effect of power on duty cycle on the pulsed RF discharge and the pulsed RF plasma jet array

The effect of power on duty cycle on the pulsed RF discharge...

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IEEE International Conference on Plasma Science (ICOPS)

作者： D. W. Liu National State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology WuHan Hubei China

Summary form only given. Nowadays biomedical application of atmospheric pressure glow discharges (APGD) known as plasma medicine has received growing attention due to their economic and technological impact. Although RF plasma has high density of reactive specie, the gas temperature of hundreds degrees prevent its biomedical application. However, the pulsed RF plasma decreased the gas temperature to 310±10k by reducing RF power ontime. Although the different RF power on time leaded to the changing of pulsed RF plasma reactivity, our study suggested on the condition of the same RF power on time, the changing of pulse frequency and duty on cycle affected the peak current, optical emission intensity of the pulsed RF plasma. On the other hand, the parallel plate discharge has the advantage of large area processing, so the sterilization effect of the pulsed RF discharge was analyzed by putting a semipermeable membrane with E. Coli on the electrode. Finally, because plasma jet can provide plasma not spatially bound, by keeping the same power on duty cycle, the difference of propagation characteristics between the pulsed RF plasma jet array and the pulsed DC jet array are analyzed. The plasma plume structure of pulsed RF jet array is same as stable DC discharge, and the strong electric field leaded to growing plasma bullet in the launching period of the pulsed DC jet array. The reactivity of pulsed RF jet array is stronger than that of pulsed DC jet array.

关键词： Radio frequency Arrays Discharges (electric) Plasma temperature Physics electromagnetics

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A self-calibration method for high-precision direct current comparator

A self-calibration method for high-precision direct current ...

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Conference on Precision electromagnetic Measurements (CPEM)

ISBN: (纸本)9781467304399

To solve the problem of calibrating high-precision heavy direct current comparator and related metering device, a self-calibration method based on small current differential principle is proposed, and the formulas based on the method are derived. This method fairly prevents the difficulty from measuring weak signal, and can accurately and easily calibrate 1×10 -5 ~1×10 -7 current ratio-error for high-precision direct current instruments by choosing appropriate measurement parameters based on the formula in this paper. And the validity of the method is proved by experimental data.

关键词： Current measurement Calibration Mathematical model Equations Educational institutions Standards Resistors

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A novel high-precision current adder based on dc comparator

A novel high-precision current adder based on dc comparator

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Conference on Precision electromagnetic Measurements (CPEM)

作者： Shiyan Ren Yumeng Zhang Donghui Cai State Key Laboratory of Advanced Electromagnetic Engineering and Technology College of Electrical and Electric Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781467304399

To solve the problem of calibrating current summation measurement system, a novel high-precision current adder based on current comparator principle is presented. It contains primary windings of six channels, feedback winding and calibrating winding. The total 24 windings' turns of such six channels can be selected skillfully according to the method of minimum common divisor, so that the sum of measured currents is indicated by the adder's feedback current. And experiments show that its accuracy is better than 5×10 -5 .

关键词： Adders Windings Current measurement Calibration Standards Accuracy Electrical resistance measurement

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A Driven Model Research of a Parallel Coil Gun

A Driven Model Research of a Parallel Coil Gun

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2012 International Conference on Mechanical engineering and Materials(ICMEM 2012)

作者： Fang Guo YueJin Tang Li Ren Guangdong Electric Power Design Institute State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology

Compared with the coaxial coil gun, the structure of parallel coil gun is conducive to release the effective load which carried by the emitter, and easy to add the suspension device. So, for some massive emitter which could not be easy wrapped inside of the barrel, to design an open parallel coil gun with a high temperature superconducting(HTS) maglev assist device is great significance. The directions of driving force are inconsistent during the drive current pulse up and down under only one coil driven. Eliminating the resistance is an effective way to improve the emission efficiency. A new mode of single-stage and multi-stage driven is designed in this paper. The pulse link up method between the various coils is analyzed. And then a small parallel coil gun model is established in the finite element software ANSOFT. The propulsion effects of single-stage and two-stage driven are simulated. And the feasibility of this driven mode is verified by these simulation results.

关键词： electromagnetic emission Parallel coil gun Pulsed magnetic traveling wave

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Temporally resolved imaging on quenching and re-ignition of nanosecond underwater discharge

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AIP Advances 2012年第4期2卷

作者： Yang, Yong Cho, Young I. Fridman, Alexander State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan Hubei 430074 China Department of Mechanical Engineering Drexel University Philadelphia PA 19104 United States

This paper presents the temporally resolved images of plasma discharge in de-ionized water. The discharge was produced by high voltage pulses with 0.3 ns rise time and 10 ns duration. The temporal resolution of the imaging system was one nanosecond. A unique three-stage process, including a fast ignition at the leading edge of the pulse, quenching at the plateau of the pulse, and self re-ignition at the trailing edge of the pulse, was observed in a single pulse cycle. The maximum measured propagation velocity of the plasma discharge was about 1000 km/s. The possibility of direct ionization in water under high reduced electric field conditions was discussed. © 2012 Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License.

关键词： Electric discharges

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