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IEEE Conference on Industrial Electronics and Applications (ICIEA)

作者： Lezhu Chen Zhoujun Jia Key Laboratory of Power Electronics & Motion Control Anhui University of Science and Technology Maanshan Anhui China State Key Laboratory of Power System Tsinghua University Beijing China

The configuration and principle of shunt active power filter is introduced briefly in this paper. A digitally controlled shunt active power filter based on double DSP is designed for the three-phase four-wire system. The main circuit of the shunt active power filter selects a four-leg voltage-source inverter, and a dynamic hysteresis-band current control is used to track the current. A control strategy based on the instantaneous reactive power theory is given in consideration of the source voltage becoming distorted and unbalanced. The facility can compensate harmonic and reactive power completely for three-phase four-wire system. The hardware configuration, flow chart of software, derivation of compensating signal and derivation of PWM waves are analyzed. The validity and correctness of the filter are proved in experiment.

关键词： Active filters Digital signal processing power harmonic filters Pulse width modulation Digital control control systems Circuits Pulse width modulation inverters Hysteresis Current control

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Effects of interfacial pressure on tracking failure at XLPE cable joint by analyzing discharge light distribution

Effects of interfacial pressure on tracking failure at XLPE ...

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IEEE International Conference on Solid Dielectrics (ICSD)

作者： B. X. Du L. Gu Key Laboratory of Power System Simulation and Control of Ministry of Education Department of Electrical Engineering School of Electrical Engineering and Automation Tianjin University TJU Tianjin China

This paper investigated the effects of interfacial pressure on the discharge and tracking failure at the interface between XLPE and silicon rubber by analyzing the distribution of discharge light emitted during the failure process. The test sample was made by pressing together a piece of XLPE and a piece of transparent silicon rubber with the pressure of 20 kN/cm 2 , 100 kN/cm 2 and 300 kN/cm 2 , respectively. Test voltage was applied to a pair of plate-needle electrodes sandwiched at the interface with the insulation distance of 10 mm. The initial discharge voltage, the discharge light from discharge to tracking failure and the tracking patterns after failure were recorded with a digital camera. Then the discharge light was analyzed with an image processing method. Results show that the initial discharge voltage increases with the increase of pressure, which significantly influences the distribution characteristics of the discharge light and tracking pattern at the interface. The analysis of discharge light distribution is helpful in understanding the failure process and its mechanism at the interface between XLPE and silicon rubber found in prefabricated cable joint.

关键词： Discharges Insulation life Degradation Brightness power cables Rubber Silicon

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Application of nonlinear methods in tracking failure test of epoxy/SiO2 nanocomposite

Application of nonlinear methods in tracking failure test of...

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IEEE International Conference on Solid Dielectrics (ICSD)

作者： B. X. Du J. W. Zhang L. Gu H. J. Liu Key Laboratory of Power System Simulation and Control of Ministry of Education Department of Electrical Engineering School of Electrical Engineering and Automation Tianjin University TJU Tianjin China

This paper investigates the effect of nano-scale SiO 2 on the tracking failure properties of nanocomposites. Test samples were made by dispersing nano-scale SiO 2 powder in epoxy with the weight ratios of 0, 1, 3, 5, 7, 9 wt%. AC voltage was applied on a pair of needle-plate electrodes at the surface with the insulation distance of 10 mm. The time to tracking failure and discharge current were recorded. In order to distinguish the change of the tracking resistance from the confusing discharge current, a recurrence plot (RP) analysis of discharge current has been used. The patterns of the tracking failure were analyzed with fractal dimension (FD) method to quantify the carbonization degree. The results reveal that 3 wt% of nano-scale SiO 2 filler greatly increase the resistance to tracking failure of epoxy/SiO 2 nanocomposite.

关键词： Insulation life Degradation Discharges Surface discharges Surface treatment Loading Electrodes

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Effect of temperature on electrical tree in silicone rubber

Effect of temperature on electrical tree in silicone rubber

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IEEE International Conference on Solid Dielectrics (ICSD)

作者： B. X. Du Z. L. May Gao T. Han Key Laboratory of Power System Simulation and Control of Ministry of Education Department of Electrical Engineering School of Electrical Engineering and Automation Tianjin University TJU Tianjin China

In this paper, room temperature vulcanized (RTV) silicone rubber (SiR) was employed as test sample to investigate the relationship between electrical tree propagation characteristics and the experiment temperature. Both the structures and growth characteristics of electrical tree in SiR were observed by using a digital camera and a microscope system. Obtained results show that electrical tree in RTV SiR is white gap tree channel, which all initiate from single branch, and the width of initiative single branch channel varies a lot with the electrical tree structure. The structure of electrical tree at experiment temperature from 30°C to 90°C in RTV SiR can be classified into four categories. They are branch, bush, pine branch and bush-pine mixed tree. The distribution of tree structures changes with the experiment. At the temperature of 30°C, branch tree take up a great proportion, however, bush tree becomes the dominant structure when the temperature rise up to 60°C and 90°C. The probability of tree initiation decreases obviously with the rise of the experiment temperature from 30°C to 90°C. All kinds of electrical tree grow rapidly in the first beginning of the treeing propagation, and this process lasts only a few minutes. In addition, a new parameter, the treeing proportion is introduced to describe propagation characteristics of bush tree.

关键词： Electrodes Rubber Temperature distribution Needles power cables Cable insulation

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Analysis of Windup in Brushless DC Motor Speed Regulating system and its control

Analysis of Windup in Brushless DC Motor Speed Regulating Sy...

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The 8th World Congress on Intelligent control and Automation(第八届智能控制与自动化世界大会 WCICA 2010)

作者： Zhaoxia Xiao Hongwei Fang School of Electrical Engineering and Automation　Tianjin Polytechnic University Tianjin 300160 Chin Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Ti

The windup phenomenon caused by the current limitation and PWM voltage regulation in the brushless DC motor (BLDCM) double PI loop speed regulating system has been investigated. And the anti-windup controller has been applied to suppress the relevant windup phenomenon. The simulation illustrates that the anti-windup controller make the BLDCM speed regulating less overshoot and quickly dynamic response. And it also has the same anti-disturb performance while the BLDCM running with external load disturb and/or internal resistor, inductance and inertia variation. The results have good reference for the design of BLDCM and the performance enhancement of the BLDCM speed regulating system.

关键词： Stators Windup Torque Resistance Brushless DC motors Inductance simulation

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state of the art of hybrid excitation permanent magnet synchronous machines

State of the art of hybrid excitation permanent magnet synch...

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作者： Wang, Shanming Xia, Yonghong Wang, Xiangheng Su, Pengsheng Huang, Shaogang Zhang, Anming State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China Department of Electrical and Automatic Engineering Nanchang University Nanchang Jiangxi 330031 China Military Deputy Department Dalian 426 Factory No.1 Yanhai Jie Xigang Qu Dalian Liaoning 116005 China

ISBN: (纸本)9788986510119

The hybrid excitation permanent magnet machine (HEPMM) combines two kinds of excitation: permanent magnet (PM) and electrical excitation, so it possesses the advantages of PM machines and overcomes the incapability of regulating the excitation field. By now many HEPMM schemes have been presented. In this paper the operation principle, structure, advantages and disadvantages of these HEPMMs have been reviewed and compared in detail. These HEPMMs are classified into three types by new classification method - placement of PM and iron poles. At last novel harmonic excitation HEPMM is proposed and discussed.

关键词： Permanent magnets

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Ecological influence of dam construction and river-lake connectivity on migration fish habitat in the Yangtze River basin, China

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Procedia Environmental Sciences 2010年 2卷 1942-1954页

作者： Yujun Yi Zhifeng Yang Shanghong Zhang Ph D. State Key Laboratory of Water Environment Simulation and Pollution Control School of Environment Beijing Normal University Beijing China Professor State Key Laboratory of Water Environment Simulation and Pollution Control School of Environment Beijing Normal University Beijing China Associate Professor Renewable Energy School North China Electric Power University Beijing China

Habitat fragment owning to obstruct of dams and barriers badly affect the aquatic faunas. Many spawning sites of migration fishes are lost, and their growth and reproduction are affected. The Yangtze River with connected lakes is the most important fresh water fishery area in China. The Yangtze's four major carp species (YFMCS) are the most typical migration fish lived in this area. They reproduce in river and grow in lake. Distributaries lies between the Yangtze River and Dongting Lake are the passages for these migration fishes. Due to the construction of dams and barriers, some original passages were out of use. Up to now, only four channels exist between the river and lake, there are Songcikou, Taipingkou and Ouchikou normally called “three outlets”, and Chenglingji inlet. Diverted Water Volume (DWV) and the Percentage of Diverted Water (PDW) through the three outlets reflect the relationship between the Yangtze River and the Dongting *** variation of river-lake relation caused by dam construction, and the effect on migration fishes are discussed in this paper. The relationship of DWV and fry output in middle reach of the Yangtze river and the Dongting Lake, PDW and the percentage of the YFMCS in a total catch of fish, DWV and flux of carp fry at the Jianli station, DWV and yield of the YFMCS were analyzed. The results show that dams and barriers constructed on the Yangtze River threaten some fish species in this area, especially the migration fishes. The connectivity degree of river and lake decide the growth and reproduction of emigration fishes, the yield of the YFMCS increase by the DWV increase, and hydraulic project have important influence on reproduction of fishes. In order to reduce the ecological influence of hydropower projects, reservoir management especially in spawning season should integrate ecological demand.

关键词： River-lake relation habitat fragment migration fish Yangtze River the Yangtze's four major carp species

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Impacts of motor load on the transient stability of the MicroGrid

Impacts of motor load on the transient stability of the Micr...

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World Congress on Intelligent control and Automation (WCICA)

作者： Zhaoxia Xiao Hongwei Fang School of Electrical Engineering and Automation Tianjin Professional University Tianjin China Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University TJU Tianjin China

Transient stability of a MicroGrid in which the micro sources using the peer-to-peer and master-slave control was investigated. The P-f and Q-V droop control was used for micro sources 1 and 2. And the PQ control was used for micro source 3. The impacts of motor load on the transient stability of the MicroGrid were shown when the motor load starts, load power changes and a three-phase faults happens. And the power sharing between each micro sources and the main frequency supporting are achieved. simulation results have verified the effectiveness of the proposed control strategy.

关键词： Stability analysis power system stability Transient analysis Automation Inverters Distributed power generation

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state of the art of hybrid excitation permanent magnet synchronous machines

State of the art of hybrid excitation permanent magnet synch...

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2010 International Conference on Electrical Machines and systems, ICEMS2010

关键词： Iron Magnetic fields Windings Stator cores Rotors Stator windings Magnetic circuits

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Analysing on characteristics of lightning shielding failure of UHVAC double circuit transmission line based on leader progression method

Analysing on characteristics of lightning shielding failure ...

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Asia-Pacific Symposium on Electromagnetic Compatibility (APEMC)

作者： Zhiyong Wang Shaoan Wang Zhanqing Yu Yinan Geng Rong Zeng Jinliang He Zhizhao Li Guangzhou Power Supply Bureau China Southern Power Grid Company Limited Guangzhou China Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China

ISBN: (纸本)9781424456215

Shielding failure of lightning is the key problem for safe operation of UHV transmission lines. Taking the feature of 1000KV AC double circuit transmission lines into account, the leader progression method with proper criterion was employed. The lightning shielding failure rate of top phase, middle phase and bottom phase of two different transmission line tower types were compute, in three different geography conditions. The research work is helpful for improving the lightning performance of UHV transmission lines.

关键词： Failure analysis Lightning Distributed parameter circuits Conductors power transmission lines Transmission line theory Voltage Corona Poles and towers power system simulation

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