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Thermal analysis of air-core power reactors

ISRN Mechanical engineering 2013年第1期2013卷

作者： Yuan, Zhao He, Jun-Jia Pan, Yuan Yin, Xiao-Gen Ding, Can Ning, Shao-Fei Li, Hong-Lei State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan 430074 China

A fluid-thermal coupled analysis based on FEM is conducted. The inner structure of the coils is built with consideration of both the structural details and the simplicity;thus, the detailed heat conduction process is coupled with the computational fluid dynamics in the thermal computation of air-core reactors. According to the simulation results, 2D temperature distribution results are given and proved by the thermal test results of a prototype. Then the temperature results are used to calculate the heat flux to predict the detailed heat transfer process in the packages of the reactors. The study in this paper may be useful in the design optimization in air-core reactors. © 2013 Zhao Yuan et al.

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Experimental Study on Arc Duration under Different Atmospheres

Experimental Study on Arc Duration under Different Atmospher...

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第十三届国际机电装置会议(IS-EMD2013)

作者： Chen LI Zhenbiao LI Qian WANG Du LIU State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong Univ.of Science & TechnologyWuhan430074P.R.China

To clarify the dependence of arc duration on atmosphere, experiments were conducted under conditions of air, N2, Ar, He and CO2 with the pressure of 0.1MPa in a 14V/28V/42V circuit re spectively.A quantitative relationship between arc duration and gas parameters such as ionization po tential, thermal conductivity was obtained from the experimental ***, the inherent mechanism of influence of atmosphere on arc duration was discussed.

关键词： atmosphere arc duration quantitative relationship

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Short circuit analysis for integration of 10MW Windfarm in Nigeria at the PCC

Short circuit analysis for integration of 10MW Windfarm in N...

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IEEE General Meeting Power& Energy Society

作者： Owolabi Sunday Adio Xiangning Lin Feng Zhao Zhiqian Bo State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China Smart Grid Institute State Grid Beijing CHINA

A short circuit in a power system can cause very high currents to flow to the fault location. The magnitude of the short circuit current depends on the impedance of system under short circuit conditions. However, to study the effect of windfarm integrated into Power Holding Company of Nigeria (PHCN) which is power bureau of the country, a short circuit calculation was performed studies conducted. The analysis was carried out in two stages, one was using Thevenin equivalent to roughly check unbalance short current from PHCN external source from Kaduna substation at 132/33kV, although this was actually not part of the current studies. The second part was to performed short circuit analysis at network where the windfarm will be connected through 33/11kV level (PCC), which is for this current studies by using computer software tool (DigSILENT powerfactory). This was done to verify the withstands of capacity for the main substation equipment and the new OHLs in comparison with the 3-phase and 1-phase to ground short circuit calculated values of grid studies for the windfarm project. In the network calculation, consideration was made for both maximum and minimum short circuit conditions and it is performed according the IEC 60909 (2001) standards. However, the aim of the analysis was the assessment of the electrical parameters of the WindFarm during and after a three phase short circuit event at the 33 kV Kastina substation because this is the point where the windfarm have to be connected and also the location of the wind generators.

关键词： Software Substations Gold

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Mechanism of insulation resistance in metalized polypropylene film capacitors

Mechanism of insulation resistance in metalized polypropylen...

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Conference on Electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： Hua Li Zhiwei Li Fuchang Lin Yaohong Chen De Liu Bowen Wang Haoyuan Li Qin Zhang State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology HUST Wuhan P. R. China

Metalized polypropylene film capacitors (MPPFCs) can work under high electric fields due to the self-healing characteristic. Leakage phenomenon caused by the insulation resistance (IR) in MPPFCs is one of the important factors resulting in the reduction of the energy efficiency. The IR is directly related to the DC electric conduction mechanism in polypropylene film. This paper mainly concentrates on the IR by investigating the electrical conduction mechanism of metalized films under high electric fields. Firstly the conduction mechanism of metallized films is discussed. Secondly IR is obtained under different electric fields based on an established measurement platform The Poole-Frenkel(PF) model presented in this paper includes the field-enhanced carrier density caused by the barrier height attenuation in directions both opposite and forward to the electric field, and the field-enhanced carrier mobility. The equation for electric conductivity based on this model gives not only the usual Ohm's law at low fields but also at extremely high electric fields. And the IR calculations match well with the experimental results.

关键词： Electric fields Conductivity Films Capacitors Resistance Current measurement

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Position/force switching control based on velocity damping

Position/force switching control based on velocity damping

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2013 IEEE International Conference on Information and Automation, ICIA 2013

作者： Long, Zhili Fang, Jiwen Zhao, Jiping Chao, Zhu Shenzhen Graduate School Harbin Institute of Technology Shenzhen 518055 China Shenzhen Key Lab for Advanced Motion Control Technology and Modern Automation Equipment Shenzhen 518055 China State Key Lab for Manufacturing Systems Engineering Xi'An Jiaotong University Shenzhen 710049 China Dongguan Huazhong University of Science Technology Manufacturing Engineering Institute Dongguan 523808 China

ISBN: (纸本)9781479913343

Stable and fast switching between displacement and pressure will directly affect precision and velocity of automated equipment. Switching control between displacement and pressure, which is based on the velocity damping, is proposed for motion switching of automated equipment. At first, the control models were established by analyzing displacement control and pressure control. To solve the shortage of direct switching between displacement and pressure, switching control based on the velocity damping is presented. The effectiveness of this method is verified by using piezoelectric sensor in experiment. Compared to direct switching control, the proposed switching control becomes more accurate and faster. The measurement data shows that the maximal impact force of control system is 0.4N and the amplitude of forces of fluctuations are within the range of ±0.03N. © 2013 IEEE.

关键词： Control systems

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Room temperature direct current air plasma jet for biomedical applications

Room temperature direct current air plasma jet for biomedica...

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IEEE International Conference on Plasma Science (ICOPS)

作者： S. Wu Z. Wang Q. Huang X. Lu K. Ostrikov State key laboratory of advanced electromagnetic engineering and technology Huazhong University of Science and Technology Wuhan Hubei China Huazhong University of Science and Technology Wuhan Hubei CN

Summary form only given. Atmospheric-pressure room-temperature plasma jets are commonly used in plasma medicine, nanotechnology, as well as surface and materials processing. Most of the applications require room-temperature operation while completely avoiding the glow-to-arc transitions. To meet these requirements, the atmospheric plasma jets are usually sustained in noble gases. However, this is very challenging for the open-air operation. Moreover, the cross-sections of the plasma plumes are typically very small, which make large-area surface processing particularly difficult. One promising way to overcome this shortcoming is by using the plasma jet arrays. However, since the individual plasma plumes generated by the arrayed plasma jets are in most cases independent and do not merge in open air, it is very difficult to achieve uniform plasmas and surface treatment effects. In this paper, we demonstrate a homogenous cold air plasma glow with a large cross-section generated by a direct current power supply. There is no risk of glow-to-arc transitions, and the plasma glow appears uniform regardless of the gap between the nozzle and the surface being processed. Detailed studies show that both the position of the quartz tube and the gas flow rate affect the plasma characteristics. Further investigation indicates that the residual charges trapped on the inner surface of the quartz tube may be responsible for the generation of the air plasma plume with a large cross-section. Moreover, the spatially resolved optical emission spectroscopy reveals that the air plasma plume is uniform as it propagates out of the nozzle. The air plasma plume with remarkable improvement of the plasma uniformity is used to improve the bio-compatibility of a glass coverslip over a reasonably large area. This improvement is demonstrated by a much more uniform and effective attachment and proliferation of human embryonic kidney 293 (HEK 293) cells on the plasma-treated surface.

关键词： Surface treatment Educational institutions Australia Electron tubes Plasma temperature laboratories

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Analysis of d- and q-axis inductances and saliency ratios in interior permanent magnet machines with fractional-slot concentrated- windings considering harmonic effects

Analysis of d- and q-axis inductances and saliency ratios in...

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International Conference on Electrical Machines and Systems (ICEMS)

作者： Xiaolong Zhang Ronghai Qu Hong Chen Jian Luo State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China UCAS EV Co. Ltd Shanghai China

The interior permanent magnet (IPM) machine with fractional-slot concentrated-windings (FSCW) has become a popular research topic owing to their novel structures and attracting potentials. This paper is focused on inductances and saliency ratios in IPM FSCW machines with different pole and slot combinations. Analytical expressions of inductances and saliency ratios are derived using harmonic analysis method (HAM) and their features and trends are concluded. The concept of dq-axis equivalent windings containing harmonic components is proposed to help better understand these features and trends. It explains the phenomenon that configurations with fewer stator slots and fewer winding layers have lower saliency ratio. Theoretical conclusions are verified by finite-element (FE) method.

关键词： Windings Harmonic analysis Inductance Power capacitors Rotors Atmospheric modeling Stator windings

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P-70: Multilayer Silicon and Silicon Oxide Subwavelength Grating as a Reflective Polarizer in Visible Region

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SID Symposium Digest of Technical Papers 2014年第1期45卷

作者： Su Pan Hoi-Sing Kwok State Key Lab on Advanced Displays and Optoelectronics Department of Electronic and Computer Engineering Hong Kong University of Science & Technology Clear Water Bay Kowloon Hong Kong

We proposed a novel visible polarizer based on multilayer silicon and silicon oxide alternative subwavelength grating and its optical characteristic is numerically investigated by finite difference time domain method. The reflectance of TE mode and transmission of TM mode are above 90% with extinction ratio up to 10 3 . Moreover, the proposed polarizer also has wide angular field and large fabrication tolerance.

关键词： polarizer subwavelength grating FDTD

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P-120: Nucleation-control Bistable Twist Nematic Display

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SID Symposium Digest of Technical Papers 2014年第1期45卷

作者： Man-Chun Tseng Chung-Yung Lee Tsz-Kin Ho Hoi-Sing Kwok State Key Lab on Advanced Displays and Optoelectronics Department of Electrical and Electronic Engineering Hong Kong University of Science Technology Clear Water Bay Kowloon Hong Kong

A fast π bistable twist nematic (π-BTN) liquid crystal display controlled by nucleation process is developed. The nucleation induced by the patterned spacer inside the cell. The response time is fast and it depends ...

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The application of Bayesian network theory in transformer condition assessment

The application of Bayesian network theory in transformer co...

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IEEE PES Asia-Pacific Power and Energy engineering Conference (APPEEC)

作者： Jiangtao Quan Ling Ruan Zhicheng Xie Xingdong Li Xiangning Lin The State Grid Key Laboratory of On-site Test Technology Hubei Electric Power Test & Research Institute Wuhan China The State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

In order to assess transformer's status and forecast its potential fault, this paper applied Bayesian network classifier into transformer fault diagnosis, combined with dissolved gas analysis and other electrical test results, and thereby created a transformer fault synthetic diagnosis method. Build up transformer's fault diagnosis model based on Naive Bayesian Classifier and Tree Augmented Naive Bayesian Classifier respectively, and verify their validity by instance.

关键词： Oil insulation Power transformer insulation Bayes methods Circuit faults Fault diagnosis Grounding

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