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IEEE International Conference on Plasma Science (ICOPS)

作者： Xiaobing Zou Rui Liu Xinxin Wang Guixin Zhang Chengmu Luo Min Han Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

Summary form only given. Between the output electrodes of a 500 kV/400 kA/100 ns pulsed-power generator, two Al wires each with diameter of 10-100 mum crossing and touching at a single point constitute an "x" shape load. The cross position explodes first and then pinches axially to form so-called X-pinch plasma as current is delivered to the "x" wires. In order to analyze the energy spectra of ion beams emitted from x-pinch, a compact Thomson spectrometer was designed and constructed. It consists of an entrance window, a pair of small permanent magnets, an exit pinhole, and a high sensitive nuclear track detector of CR-39 plastic plate. Ion beams experience deflections in the electromagnetic field, and then hit the target (CR-39 plastic) at different positions and form craters, then the craters form different parabolic track with different ratio of ion mass to ion charge. By counting the track density of the parabolas, charge state resolved energy spectra of ion beams were obtained

关键词： Ion beams Plasmas Target tracking Wires Plastics Electrodes Pulse shaping methods Pulse generation Shape Magnetic analysis

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Implementation of Fault Detection and Diagnosis System for control systems in Thermal power Plants

Implementation of Fault Detection and Diagnosis System for C...

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World Congress on Intelligent control and Automation (WCICA)

作者： Xiaobin Huang Hongjing Qi Xuan Liu Department of Automation Key Laboratory of Equipment State Monitoring and Control for Power Station MOE North China Electric Power University Beijing China Department of Equipment Engineering Zhangshan Power Generation Company Limited Changzhi Shanxi China

A software-based system was developed for fault detection and diagnosis (FDD) of control systems in typical thermal power plants. For the large-scale industrial processes as thermal power plants, a three-level configuration to build a realtime FDD system is proposed. This configuration includes the component level, loop level and system level. Developed algorithms for each level and systematic approaches and steps to implement the overall diagnostic system are discussed. The developed system has been applied to a real-world thermal power plant to monitor its main control systems

关键词： Fault detection Fault diagnosis control systems power generation Automatic generation control power system reliability Large-scale systems Boilers Electrical fault detection Thermal engineering

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Progressively Converging Deadbeat control for UPS Inverter

Progressively Converging Deadbeat Control for UPS Inverter

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Annual IEEE Conference on Applied power Electronics Conference and Exposition (APEC)

作者： Y.D. Liu Y. Xing L.P. Huang M. Sakane State Key Laboratory of Security Control & Simulation of Power Systems and Large Scale Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China College of Automation Engineering Nanjing University of Aeronautics and Astronautics Jiangsu China GS Yuasa Power Electronics Limited Osaka Japan

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Experimental analysis of DC pre-excitation for 3-level inverter-motor system

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2006年第3期26卷 159-163页

作者： Bai, Hua Zhao, Zheng-Ming Hu, Xian Chen, Xin State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing 100084 China South Automation Company Nanjing 210003 China

In the AC adjusting speed system, the significant current impulse frequently occurs in the starting process while the output torque is sufficient. This would damage the power electronics device, cause the unbalance of neutral point in three-level NPC topology, and deteriorate the starting performance. In this paper, a DC pre-excitation strategy, which limits the starting current and enhances the electromagnetic torque via establishing the flux linkage before starting process, is proposed to the three-level inverter under analysis on the mechanism of the above large current. The relevant experiments present its eminent effect on the 380 V/160 kW inverter-motor system. Also this paper discuss the feasibility of its application in high voltage high power inverter.

关键词： Induction motors

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Risk-based study on under voltage load shedding schemes

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2006年第19期26卷 18-22页

作者： Dai, Jian-Feng Zhu, Ling-Zhi Zhou, Shuang-Xi Lu, Zong-Xiang State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Beijing 100084 China

A risk based method is proposed to design under voltage load shedding (UVLS) scheme. Different with traditional methods, the proposed one employs a series of risk indices, which are obtained based on a full-scale contingencies analysis, to determine the operating parameters of load shedding. According to this method, the load bus, in which the UVLS can exert itself with the highest efficiency to prevent voltage collapse, is selected as the first candidate to execute load shedding. And the amount of loads to be shed is identified though a relationship between risk values and shedding amount. The selection of shedding time conforms to the principle that the compound risk brought by failed shedding and unexpected shedding must be the minimum. Experiments conducted for IEEE 39-bus system reveal that the proposed method redound to identify the location, amount and time of load shedding more accurately and reasonably due to taking into account a great deal of uncertain factors.

关键词： Electric load shedding

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Study on probability of voltage instability based on the stochastic characteristic of load margin index

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2006年第13期26卷 26-30页

作者： Dai, Jian-Feng Wang, Hai-Chao Zhou, Shuang-Xi Lu, Zong-Xiang Zhu, Ling-Zhi State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Beijing 100084 China

In order to make up the deficiency of traditional analytical method used in the research of voltage stability problem, we need to know the probability information concerned with voltage instability. Therefore, this paper proposes a method to calculate the probability of voltage instability based on the stochastic characteristic of load margin index. This method firstly determines the stochastic characteristic of load margin index through an analysis about the randomicity of parameters which tie up with the tracing of critical point in continue power flow computation, and then figures out the probability of voltage instability by using moment and cumulate method. Owing to take into account more uncertain factors' influence on the voltage stability, the result acquired by this method is much more accurate and reasonable. A numerical simulation based on IEEE 39-bus system reveals that the proposed method works properly.

关键词： Electric power systems

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Improved simultaneous extrapolation in sharp impulse signals in time and frequency domains

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2006年第18期26卷 133-137页

作者： Zou, Jun Guo, Jian He, Jin-Liang Zhang, Bo Teng, Wen-Rui State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing 100084 China Dept. of Electrical Engineering Henan University of Technology Zhengzhou 450042 China

The characteristic of the transient response of the grounding system takes on a fast rising and slow damping with the lightning excitation. An improved simultaneous time and frequency domain extrapolation method is presented based on Hermite function expansion, which takes the above mentioned characteristic of the transient signal into account, using early time response and low-frequency data, the complete electromagnetic response is generated. By using mutually complementary data, simultaneous extrapolation in time and frequency domains are carried out by using the Hermite polynomials as the basis function. However, the extrapolation method is not suitable to deal with the transient response with the fast pulse excitation. The improvement for the extrapolation method is to pre- and post-process the transient response data with the fast pulse excitation. As a pre-processed procedure, in order to reduce the condition number of the matrix used for determined the coefficient of basis function, the scale transformation is used in time and frequency domain respectively, and the data in time domain is smoothed and padded with zero. An adaptive algorithm to determine the order of Hermite function is also proposed. As a post-processed step, the transient data are smoothed by using GPOF to obtain a convergent result. The numerical example and the field measurement are presented to illustrate the application of this methodology. The method proposed enhances the ability of the simultaneous time and frequency extrapolation techniques.

关键词： Signal processing

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Adaptive Galerkin approach of the indirect boundary element method for calculating 3D linear magnetostatic field

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2006年第1期26卷 96-100页

作者： Zou, Jun He, Jin-Liang Yu, Hai-Yu Teng, Wen-Rui State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing 100084 China Dept. of Electrical Engineering Henan University of Technology Zhengzhou 450042 China

The indirect boundary element method has some special advantages for the 3D linear magnetostatic field calculation by using the equivalent magnetic surface charge. In order to improve the accuracy of solutions and decrease the computational costs, an adaptive Galerkin approach to solve the magnetostatic integral equation is presented by using the h-type refinement technology. The basic idea of the proposed approach can be summarized as follows. The error of magnetic flux density is globally minimized in the Galerkin sense in the implementation, so the continuity error of magnetic flux density of each element can be served as a criterion to guide the adaptive refinement. The singularity of geometric corners and edges can be overcome due to the scheme of the discretization of the integral equation with Galerkin's approach. In addition, a local resolution technology is proposed, which leads to the minimal refined unknown. The numerical examples show the proposed method is efficient and accurate by comparison to the analytical solutions and the measured results.

关键词： Magnetic fields

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Calculation on the thermal field of the water cooling stator of three-gorge hydro-generator

Calculation on the thermal field of the water cooling stator...

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ICEMS 2005: 8th International Conference on Electrical Machines nd systems

作者： Wang, H.Y. Su, P.S. Wang, X.H. Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing 10084 China

ISBN: (纸本)7506274078

To simplify the calculation of winding bar temperature for the condition monitoring of the water cooling stator of Three-Gorge Hydro-Generator, this paper calculates three of two-dimension thermal fields. Using the three fields simulates the different section along the axial direction of the generator. The total amount of heat taken away by water can be calculated by weighting the result of three fields on the total axial length of them. Four groups of thermal-fields with different outlet-water temperature are calculated by using ANSYS multi-physical software. The calculation results of temperature of measurement-point between up-layer and down-layer bars in stator are partly supported by the measurement data. And the relatively error between the heat taken by cooling-water and the heat generated by the stator bar is always less than 5%.

关键词： Stators

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Research on the prediction-model of the surface-temperature of large oil-immersed power transformer

Research on the prediction-model of the surface-temperature ...

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ICEMS 2005: 8th International Conference on Electrical Machines nd systems

ISBN: (纸本)7506274078

In order to detect the abnormal temperature of large oil-Immersed power transformer earlier, this paper presents a new prediction-model of surface-temperature for the transformer to predict the normal surf ace-temperature. And to compare the difference between the predicted value and the measured value can judge If the condition of the transformer Is fit to operate. The model parameters are estimated from the field data by using the Partial-Least-Square method, which overcomes the instability of results estimated by using the traditional Least-Square method. Furthermore, the appropriate amount of data for the parameter estimation was decided according to the principle of Heat Transfer and the characteristics of the predicted deviation, such as mean, variance and normal distribution. The prediction model is verified from the accuracy of results predicted with one year of field data.

关键词： Electric transformers

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