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IEEE/PES Transmission and Distribution Conference and Exposition: Latin America

作者： K. L. S. Shenxing X. Dong Z. Bo State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China Tsinghua University Beijing Beijing CN State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China AREVA T&D Automation슠and Information Systems Stafford UK

Non conventional instrument transformer (NCIT) and IEC 61850 are crucial technologies in digital substations. But they bring some new uncertainties to protection IEDs, especially the time synchronization issue in current differential protection. The paper analyzes the time delay of transferring sampled values from NCIT to current differential relay in NCIT and IEC61850 based digital substation, then finds out the delay-non-deterministic problem, at last presents a novel current differential protection scheme by using phase-locked loops (PLL ) technology.

关键词： Substations Delay effects Ethernet networks Phase locked loops IEC Synchronization Data communication

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Optimal design of SVC-based subsynchronous damping control using genetic and simulated annealing algorithm

Optimal design of SVC-based subsynchronous damping control u...

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International Conference on Information and Automation (ICIA)

作者： Tingzhi Yang Xiaorong Xie Shiyu Liu Donghui Zhang State Key Laboratory of security control & simulation of power systems and large-scale generation equipments Department of Electrical Engineering Tsinghua University Beijing China

In this paper, an optimal approach based on genetic and simulated annealing algorithm (GASA) is prosposed to design more effective and robust subsynchronous damping control (SSDC) of Static Var Compensator (SVC) for multimodal SSR damping improvement. A practical multi-machine series compensated power system suffering multimodal SSR has been studied to demonstrate the effectiveness of the approach. The developed SSDC comprises independent modal control path, each with separate feedback gains and phase-shifts, to damp different torsional mode. The problem of simultaneously tuning all the control parameters for robust stabilization of multiple torsional modes over various system conditions is formulated into a standardized constrained optimization problem. With the proposed GASA, the problem is efficiently solved and the SVC SSDC is optimized. Both eigenvalue analyses and electromagnetic simulations have been conducted on the test system to validate the approach and the designed SVC-based SSDC.

关键词： Static VAr compensators Damping Generators Gallium power system dynamics Optimization power systems

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Current differential protection based on Non-Conventional Instrument Transformer and IEC61850

Current differential protection based on Non-Conventional In...

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International Universities power Engineering Conference (UPEC)

作者： Kun Liu Xinzhou Dong Zhiqian Bo State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China AREVA T&D Automation슠and Information Systems Staffordshire UK

Non Conventional Instrument Transformer (NCIT) and IEC 61850 are crucial technologies in digital substations. But they bring some new uncertainties to protection IEDs, especially the time synchronization issue in current differential protection. The paper analyzes the time delay of transferring sampled values from NCIT to current differential relay in NCIT and IEC61850 based digital substation, then finds out the delay-non-deterministic problem, at last presents a novel current differential protection scheme by using Phase-Locked Loops (PLL ) technology.

关键词： Substations Delay effects Synchronization IEC Phase locked loops Data communication Ethernet networks

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PSIM and SIMULINK Co-simulation for three-level adjustable speed drive systems

PSIM and SIMULINK Co-simulation for three-level adjustable s...

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IPEMC 2006: CES/IEEE 5th International power Electronics and Motion control Conference

作者： Yongchang, Zhang Zhengming, Zhao Baihua Liqiang, Yuan Haitao, Zhang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)1424404487

Applying co-simulation technology is a very important trend in power electronics simulation, which can make full use of the merits of different software to improve the efficiency of building up a system. In this paper, a simulation platform for three-level adjustable speed drive (ASD) based on co-simulation of PSIM and SIMULINK is presented, which includes the interface between PSIM and SIMULINK, main circuit in PSIM, space vector pulse width modulation (SVPWM), dead time and minimum pulse width, view of output voltage and its Fourier analysis in SIMULINK Based on this platform, the cause of large current when motor starts is studied. simulation and experimental results show that the minimum pulse width contributes a lot for the large starting current of the ASD. In conclusion, applying the simulation platform introduced in this paper, the dynamic behavior of the three-level ASD can be easily studied, which reduces the cost and improves efficiency at the same time compared to hardware investments, and may help to realize the optimal design of the ASD in practice. © 2006 IEEE.

关键词： Efficiency

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Dynamic Equivalent Circuit Design In Three-level High Voltage Inverters Based On Functional Model of IGCT

Dynamic Equivalent Circuit Design In Three-level High Voltag...

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Twenty-Second Annual IEEE Applied power Electronics Conference and Exposition (APEC 07), vol.2

作者： Hua BAI Zhengming Zhao Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

The integrated gate commutated thyristors (IGCTs) are commonly used for construction of high voltage three-level PWM controlled voltage source converter/inverters. When the output voltage is greater than the maximum rated voltage, IGCTs are connected in series. To ensure the safe and reliable operation of the converter/inverters, special measures are required to equalize the voltages across the IGCTs connected in series. An effective method for balancing voltages is to use resistors for static voltage balancing and RC snubber circuits for dynamic voltage balancing. However, most of the previous research work reported in the literature focused on the dynamic circuit design for converters of the BUCK topology. Trade off is made only between the performance of dynamic voltage balancing and the turn-on loss without any consideration of di/dt endurance and any procedural steps, which makes the design procedure not suitable for converters of the three-level topology. Based on a functional model of IGCTs, this paper presents a procedure for optimum design of the dynamic voltage balancing circuit for a 6 kV/1250 kW inverter. The specific transient processes in the three-level topology with dynamic snubber circuit are simulated and the mechanisms are analyzed, which is absent in the previous work.

关键词： IGCT Dynamic equivalent circuit Three-level inverter Dead band

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Vector control for a twelve-phase synchronous motor

Vector control for a twelve-phase synchronous motor

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International Conference on Electrical Machines and systems (ICEMS)

作者： Dejia Zhou Zhengming Zhao Shanming Wang Jianyun Chai State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering and Applied Electronic Technology Tsinghua University Beijing 100084 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China

A twelve-phase synchronous motor with four Y-connected 3-phase symmetrical windings displaced in turn by 15deg is modeled by using flux linkages as state variables, and an optimized method for the vector control is proposed with the simulation results. The observing model for magnetizing flux linkage at the direct-axis is derived whereby a vector control scheme of a twelve-phase synchronous motor, and related simulation is constructed in this paper. Using switch blocks to model the functions of twelve-phase voltage-fed inverter is convenient for simulating the driving system. The results of the simulations show that the torque and magnetizing flux linkage can be controlled separately, and the dynamic characteristics of the motor are satisfied with the operating requirements.

关键词： Machine vector control Synchronous motors Couplings Magnetic separation Magnetic flux Switches Optimization methods Voltage Inverters Torque control

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Safe Operating Area of High power Three-level Neutral Point Clamped Voltage Source Inverters Equipped with IGCTs

Safe Operating Area of High Power Three-level Neutral Point ...

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International Conference on Electrical Machines and systems 2007(ICEMS2007)(第十届国际电机与系统会议)

作者： Liqiang YUAN Zhengming ZHAO Fanbo HE Mohd Eltawil State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University China

To design and analyze the behavior of high power inverter, the definition and application of the inverter's own safe operating area (SOA) are presented in this paper. The relation between the switch devices behaviors and the other components of the inverter is playing a key role in the description of the novel SOA. Based on the proposed idea, the optimization of a real 1.25MW/3.3kV inverter equipped with IGCTs is presented and analyzed. The corresponding experimental results are shown.

关键词： Voltage Pulse width modulation inverters Semiconductor optical amplifiers Switches Induction motors power harmonic filters power system simulation Variable speed drives Circuits Topology

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Analysis and Experimental Study of Slot Effect in Synchronous Reluctance Permanent Magnet Motors

Analysis and Experimental Study of Slot Effect in Synchronou...

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International Conference on power Electronics and Motion control (IPEMC)

作者： Wei Guo Zhengming Zhao Yingchao Zhang Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

Slot effect in synchronous reluctance motors with permanent magnet assisted (SR-PM) are deeply analyzed, reduced and verified by experiments in this paper. The three different type sample SR-PM motors are introduced firstly. Then how the rotor layer numbers affect the torque characteristics is deeply analyzed, including the torque-angle, steady operating torque and position-setting torque. Then the reduction method is presented with simulation results. The detail experiment results are given in the final. The results shows that both more layers and stator slot skewing can reduce the teeth harmonics. However for the rotor with sintered NdFeB magnet, stator slot skewed is the best way because it only has few layers due to manufacture reason

关键词： Magnetic analysis Permanent magnet motors Reluctance motors Rotors Synchronous motors Torque Stators power system simulation Manufacturing Servomotors

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Analyzing the energy spectra of ion beams emitted from x-pinch plasma

Analyzing the energy spectra of ion beams emitted from x-pin...

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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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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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