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Architecture and fault identification of wide-area protection system

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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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 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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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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Enhancements to the Cumulant Method for probabilistic load flow studies

Enhancements to the Cumulant Method for probabilistic load f...

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IEEE General Meeting Power& Energy Society

作者： Defu Cai Jinfu Chen Dongyuan Shi Xianzhong Duan Huijie Li Meiqi Yao State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China Alstom Grid Research and Technology Center Shanghai China

This paper introduces two enhancements to the Cumulant Method (CM) for probabilistic load flow studies. The first one is to handle the correlation between input random variables. This enhancement models the correlated input random variables as a function of several independent ones by Cholesky decomposition and modifies CM equations. The second one is to adopt Monte Carlo sampling techniques to calculate the cumulants of input random variable with complex distribution function. The accuracy and efficiency of the proposed approaches are verified against Monte Carlo simulation method on modified IEEE 14-bus system. The impacts of wind speed correlation on power system operation are investigated by the proposed approaches.

关键词： Random variables Correlation Vectors Distribution functions Electronic countermeasures Matrix decomposition Load flow

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DISCHARGE CHARACTERISTIC TESTS UNDER SALTY AND ACIDITY HAZE SIMULATING CONDITIONS

DISCHARGE CHARACTERISTIC TESTS UNDER SALTY AND ACIDITY HAZE ...

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The ⅪⅩ International Conference on Gas Discharges and Their Applications

作者： CHEN WEIMIN HE ZHENGHAO WANG GUOLI MA JUN ZHANG XIAOFEI XU TAISHENG ZHAO HUAN LIU QINGYING State Key Laboratory of Advanced Electromagnetic Engineering and Technology(Huazhong University of Science and Technology) Research Institute of China Southern Power Grid Co.Ltd.

ISBN: (纸本)9771003651221

The research on electric discharge characteristic in haze is *** may be conducive to improve the high voltage transmission line insulation design and *** paper presents recent research work of discharge characteristic tests under the haze conditions simulated in salty or *** rode-plane gap breakdown and flashover along insulator string surface are involved in the *** show that the discharge voltage is different while the concentration in salty or acidity is *** discharge has its own performance when the condition is in salty and in acidity respectively. Another important phenomenon deduce from the results is that the lowest discharge voltage in simulating haze is no obviously difference between rode-gap and insulator string while the equivalent distance are *** implies that the worst haze may cause discharge directly in space path and not along the surface of the insulator *** may lead to trip the line and the system. Some more research work is expected to do further.

关键词： DISCHARGE CHARACTERISTIC TESTS UNDER SALTY AND ACIDITY HAZE SIMULATING CONDITIONS

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An analytical method for determining circuit parameter of a solid rotor induction motor

An analytical method for determining circuit parameter of a ...

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International Conference on Electrical Machines and Systems (ICEMS)

作者： Siyuan Guo Libing Zhou Tong Yang State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China Beijing aerospace control device institute Beijing China

This paper presents an analytical method for prediction of equivalent circuit parameter of a solid rotor induction motor with smooth surface. The solid rotor induction motor is similar to a linear induction motor in electromagnetic properties. Therefore, the method of performance calculation for LIM can be applied for the solid rotor induction motor. On the principle of complex power from the equivalent circuit identical to that from electromagnetic field, we develop an analytical model based on 2D polar coordinates and account for the influence of nonlinearity and hysteresis.

关键词： Rotors Solids Induction motors Equivalent circuits Magnetic hysteresis Stator windings Permeability

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