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International Conference on Electrical Machines and systems (ICEMS)

作者： Han Beibei Sun Xudong Jiang Jianguo State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

In view of the impossibility of current measurement in actual grounding plane in power electronic equipment, an equivalent circuit model is set up in this paper using the partial element equivalent circuit (PEEC) method to simulate and calculate current distribution in grounding plane. The inductance parameters calculated are fairly coincident with experiment results, and some conclusions of current distribution are summarized. It is shown that the equivalent circuit model using PEEC method presented in this paper is a feasible and promising way to model and calculate current distribution in grounding plane

关键词： Current distribution Grounding Equivalent circuits Electromagnetic compatibility Conductors power electronics power system modeling Circuit simulation Impedance Current measurement

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Accurate flux observer based on distributed multi-processor in MV adjustable speed drive system

Accurate flux observer based on distributed multi-processor ...

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International Conference on Electrical Machines and systems (ICEMS)

作者： Liu Shu Liu Jianzheng Zhao Zhengming Yuan Liqiang Bai Hua Zhang Haitao Department of Electrical Engineering and Applied Electronic Technology State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

This paper presents an accurate flux observer used in distributed multi-processor (DMP) adjustable speed drive systems. The stator flux linkage is estimated with a full-order observer, while the rotor speed is identified by using Lyapunov theorem. In order to improve the system performance in a wide speed range, the stator resistance is estimated simultaneously. In this paper, the structure of the DMP system, the principle of the full-order observer and the method for identifying the rotor speed and state resistance are all described in details. Relevant simulation results based on MATLAB/SIMULINK are given to prove the performance of the method. Experiments of a real system also verify the feasibility of this scheme

关键词： Variable speed drives Stators Observers control systems Mathematical model Couplings Torque control Optimal control Sampling methods Pulse width modulation

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A novel fiber-CAN-based real time communication system for MV-ASD systems

A novel fiber-CAN-based real time communication system for M...

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International Conference on Electrical Machines and systems (ICEMS)

作者： Jue Qian Zhengming Zhao Haitao Zhang Hua Bai Liqiang Yuan Department of Electrical Engineering and Applied Electronic Technology State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

The voltage increment in MV-ASD systems deteriorates the electromagnetic environment, therefore the communication system is facing a formidable challenge in the attempt to achieve the numerous real-time interactivities among those subsystems under such electromagnetic circumstance. This paper focuses on the real-time communication system for the MV-ASD systems, in which electromagnetic compatibility (EMC), real-time performance and system reliability are considered simultaneously. A novel fiber-CAN network is designed and implemented, which remarkably increases EMC compared to the conventional ones. The CAN system that serves in the multiprocessor control system for the MV-ASD system with the rated power of 1 MW is implemented. From the experiment results in the MV-ASD system with a 690 kW motor, it can be verified that the requests of timing performance and the reliability for the communication system are well accomplished

关键词： Optical fiber communication Real time systems control systems Communication system control Circuits Torque control Electromagnetic compatibility Pulse width modulation inverters Optical fiber devices power system simulation

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Study on new leading-out mode of neutral points of large-sized turbo-generator

Study on new leading-out mode of neutral points of large-siz...

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International Conference on Electrical Machines and systems (ICEMS)

作者： L. Gui X.H. Wang Y.G. Sun W.J. Wang Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China

To supply overall protection for large-sized turbo-generator, a new approach about leading-out mode of neutral points and disposition of protection schemes is firstly presented in this paper. To check up the sensitivity of the new protection scheme, two turbo-generators with 300 MW are simulated using the multi-loop method. simulation results indicate the performance of the new protection scheme is much better than that of the traditional protection. Without adding hardware investment, the new leading-out mode is agreed by electrical machine designers.

关键词： power system protection Stator windings Current transformers power system simulation power generation Sun Laboratories power system control power systems Hardware

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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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International Conference on Electrical Machines and systems (ICEMS)

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

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 surface-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： power transformers Oil insulation Temperature sensors Predictive models Parameter estimation Heat transfer Temperature measurement Thermal resistance power system simulation Surface fitting

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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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International Conference on Electrical Machines and systems (ICEMS)

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

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： Cooling Stator cores Stator windings Solids Bars Heat transfer power system simulation Temperature Thermal engineering Condition monitoring

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Parameter calculation for induction machine rotor bar with non-sinusoidal current

Parameter calculation for induction machine rotor bar with n...

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International Conference on Electrical Machines and systems (ICEMS)

作者： Xinzhen Wu Xiangheng Wang Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)7506274078

To evaluate the rotor bar parameters of an induction machine with the non-sinusoidal current, a new analysis approach, which employs the circuit analysis theory instead of electromagnetic field theory to count the skin effect, is proposed. In the presented method, a rotor bar is divided into many thin-layers with their own parameters derived. The superposition principle is proven for the calculation of total bar losses and slot magnetic energy due to the non-sinusoidal current composed of sinusoidal components with different frequencies, which shows the parameters of the bar can be expressed with the parameters at respective frequencies. For given examples, the parameters at different frequencies are calculated, and the results are verified by the analytical method or the finite element method.

关键词： Induction machines Skin effect Frequency Rotors Electromagnetic analysis Circuit analysis Magnetic losses Magnetic analysis Finite element methods power system simulation

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Optimized design of main protection configuration scheme for internal faults of Shawan generator

Optimized design of main protection configuration scheme for...

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International Conference on Electrical Machines and systems (ICEMS)

作者： Yuguang Sun Xiangheng Wang Lin Gui Weijian Wang Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)7506274078

In order to provide high-quality protection for large- and medium-sized generators, a new feasible method of designing main protection configuration scheme for internal faults of generators is desirable. Based on calculation of all the possible internal faults with the multi-loop method, the optimized design method is illustrated through Shawan generator in this paper. With this method, the optimal protection configuration scheme, composed of the split-phase transverse differential protection, two sets of incomplete longitudinal differential protection as well as one set of single element transverse differential protection, is determined for the internal faults of Shawan generator, which has two branches in each phase. The rate of operation and double-protection of the optimal scheme both reach the maximum. In addition to that, on all the possible phase-to-phase faults, at least two kinds of protection of the optimal scheme are sure to operate correctly. The optimized scheme excels the conventional one in protection performance index, which verifies the validity of the optimized method of designing main protection configuration scheme for generators.

关键词： Design optimization Circuit faults Design methodology power generation power system protection Character generation power system simulation Performance analysis Stators Sun

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REINFORCEMENT LEARNING control FOR SHIP STEERING USING RECURSIVE LEAST-SQUARES ALGORITHM

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IFAC Proceedings Volumes 2005年第1期38卷 133-138页

作者： Zhi-peng Shen Chen Guo Shi-chun Yuan Lab of Simulation and Control of Navigation Systems Dalian Maritime Univ. Dalian 116026 China State Key Laboratory of Intelligent Technology and system Tsinghua University Beijing 100084 China

Recursive least-squares temporal difference algorithm (RLS-TD) is deduced, which can use data more efficiently with fast convergence and less computational burden. Reinforcement learning based on recursive least-squares methods is applied to ship steering control, as provides an efficient way for the improvement of ship steering control performance. It removes the defect that the conventional intelligent algorithm learning must be provided with some sample data. The parameters of controller are on-line learned and adjusted. simulation results show that the ship course can be properly controlled in case of the disturbances of wave, wind, current. It is demonstrated that the proposed algorithm is a promising alternative to conventional autopilots.

关键词： Recursive squares methods Learning algorithm Action network Ship control simulation

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Aging effect of UV radiation on SIR insulators' hydrophobicity property

Aging effect of UV radiation on SIR insulators' hydrophobici...

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Conference on Electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： Xun Wang Xidong Liang Yuanxiang Zhou State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)0780385845

Based on the simulation of ultraviolet (UV) radiation in the Sun's rays and in corona, the aging effect of UV radiation on composite insulators was studied in this paper, especially the effect on hydrophobicity properties. It is found that after irradiation with UV, no matter whether a short time of less than 24 hours or a long time of 2000 hours, the hydrophobicity and the hydrophobicity transfer properties of silicone rubber (SIR), which are described by contact angle, slowly turns better. Four different kinds of samples with different prescriptions were used in the test. As UV sources, a special setup to simulate the UV rays of corona and a xenon light to simulate the sunlight were both used. The change of rigidity of silicone rubber was also measured. Infrared spectra of the silicone rubber surface, irradiated by UV for various times, show that the content of the low molecule weight on the surface is different, and this can be due to the discrepancy of hydrophobicity properties of the samples.

关键词： Aging Testing Slabs Xenon Corona Rubber power system simulation Surface cleaning Dielectrics and electrical insulation Stress

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