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8th IEEE International Conference on Advanced power System Automation and Protection, APAP 2019

作者： Chen, Binshu Dong, Xinzhou Tsinghua University Key Lab of Control and Simulation of Power Systems and Generation Equipment Dept. of Electrical Engineering China

ISBN: (纸本)9781728117225

In LCC-HVDC hybrid grid, commutation failure is an important factor affecting system stability. When there is a fault or a large voltage fluctuation in AC line of LCC-HVDC, a commutation failure will occur. Fault current limiter (FCL) can limit the fault current and prevent commutation failure. Superconducting current limiters using superconducting materials as the core component, have no power loss and do not affect the dynamic performance of the system during normal operation. This article analyze how SFCL acts to suppress commutation failure in AC/DC hybrid systems, and describes the various types of SCFCLs and their limitations for this scene. By building simulation models of SCFCLs applied to AC line of LCC-HVDC invert, the author analyzes the effect of SCFCL on the hybrid grid. © 2019 IEEE.

关键词： Superconducting fault current limiters

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Vibration Reduction by Segmented Continuous Variable Width Pole for Rotating Armature Permanent Magnet Motors

Vibration Reduction by Segmented Continuous Variable Width P...

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International Conference on Electrical Machines, ICEM

作者： Zhanlu Yang Shanming Wang Jianfeng Hong Chao Liu State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China Navy Submarine Academy Qingdao China

ISBN: (数字)9781728199450

ISBN: (纸本)9781728199467

In order to reduce the electromagnetic vibration of rotating armature permanent magnet motor (RAPMM), this paper proposes a method to reduce vibration using the magnetic pole with segmented continuous variable width. The distribution of flux density and radial force density in air gap is calculated using analytical method. The analytical solutions of radial exciting force and bending moment exciting force on magnetic pole are obtained. Through analysis, the principle of magnetic pole width adjustment for the reduction in radial exciting force and bending moment is developed. The magnetic field, Maxwell stress, vibration deformation and acceleration of the motor are calculated using the three-dimensional finite element method. In order to validate the effectiveness of the proposed method, a comparison is performed between the proposed scheme and the other three traditional schemes. Finally, the experimental results about the four kinds of motors are compared, to validate the proposed method.

关键词： Vibrations Permanent magnet motors Prototypes Rotors Force Stator windings Permanent magnets

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Polymeric insulating materials characteristics for high-voltage applications

Nature Reviews Electrical Engineering

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Nature Reviews Electrical Engineering 2024年 516-528页

作者： Tian-Yu Wang Gui-Xin Zhang Zhi-Min Dang Jie Mao Boya Zhang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China Department of Chemical and Biomolecular Engineering University of California Los Angeles CA USA School of Chemistry and Chemical Engineering State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering Ningxia University Yinchuan China State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong University Xi’an China

Large-scale power system transmission and transformation equipment operates in high-voltage environments, placing notable requirements on the insulation strength of polymers used in core insulation frameworks. Increasing the polymer insulation performance in high-voltage environments is crucial for protecting large-capacity and integrated power equipment and ensuring the safe and stable operation of electrical devices. Here, we discuss the phenomena and the underlying mechanisms of bulk breakdown and surface flashover that lead to insulation failure in polymers and present relative strategies to increasing the performance of the insulating materials. We analyse the challenges faced by polymeric insulating materials in various extreme environments and the strategies to address them. Finally, we identify key challenges and highlight future directions and opportunities for the development of reliable polymeric insulating materials.

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Switching Current Imbalance Mitigation for Paralleled SiC MOSFETs Using Common-mode Choke in Gate Loop

Switching Current Imbalance Mitigation for Paralleled SiC MO...

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IEEE Energy Conversion Congress and Exposition

作者： Jiye Liu Zedong Zheng State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China

ISBN: (数字)9781728158266

ISBN: (纸本)9781728158273

Paralleling SiC MOSFETs is a popular way to increase the current capacity. However, due to asymmetric layout, device parameter mismatch and other factors, imbalanced switching or dynamic current is observed among the paralleled switches in multi-device paralleling application which results in unequal switching loss, challenging the security and reliability of the system. In this paper, a common-mode choke in the gate loop is proposed and analyzed to suppress the imbalanced switching current induced by asymmetric layout in a half-bridge configuration with a Kelvin-source connection. The mechanism of the proposed method is comprehensively investigated to show that though the common-mode choke is placed in the gate loop, it can also mitigate the imbalanced current caused by asymmetric power loop. And it also shows that only the leakage inductance of the choke is seen in the gate loop and thus the switching speed is not expected to be influenced. The proposed method can be easily extended to multi-device paralleling application and the switching transients is hardly influenced by the common-mode choke. simulation and experimental results are presented to verify the proposed method.

关键词： Inductance MOSFET Silicon carbide Switches Logic gates Inductors Transient analysis

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Optimization of Heterogeneous Resources Combination using Virtual power Plant based on Modern Portfolio Theory

Optimization of Heterogeneous Resources Combination using Vi...

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Sustainable power and Energy Conference (iSPEC)

作者： Qiuchen Yun Liting Tian Fang Zhang Lin Cheng School of Electrical Engineering Beijing Jiaotong University Beijing China Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China

ISBN: (数字)9781728191645

ISBN: (纸本)9781728191652

In recent years, with the development of smart grid technologies, wind turbines, photovoltaics and other renewable energy sources as well as demand-side loads have participated in grid dispatching, resulting in increased complexity of energy flows in the grid. Distributed energy resources (DERs) differ in many dimensions, such as technical attributes, operating modes, and business objectives, and its management authority also belongs to different entities, making it more difficult for grids to manage DERs. A management mode, virtual power plant (VPP), being enabled by information and communication technology, could effectively overcome the challenges with decentralized DERs and help realize the aggregation of DERs. In this paper, the interaction between customers and VPP is modeled, where VPP divides the owners of DERs into three categories according to the willingness and responsiveness of customers and balances budget costs and risks based on the modern portfolio theory. simulation with the CIGRE 20kV distribution network benchmark demonstrates that VPP could greatly meet the power consumption demand of multiple participants during operation. This paper also provides a basis for the selection of DERs aggregated by VPP. 1 1This paper is sponsored by the National key Research and Development Program (No.2017YFB0903300) and National Natural Science Foundation of china (No.51807107) 2 2This paper is sponsored by the Young Talents Support Project of the Chinese Society for Electrical Engineering (CSEE) titled “Research on key technologies for optimal operation and control of transportation energy systems”.

关键词： power demand Transportation Benchmark testing Wind turbines Smart grids Portfolios Optimization

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Electrical Tree Evolution under DC Voltages and Its Differences from AC Trees in Silicone Rubber

Electrical Tree Evolution under DC Voltages and Its Differen...

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Conference on Electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： Yunxiao Zhang Yuanxiang Zhou Ling Zhang Chenyuan Teng Zhongliu Zhou Meng Huang State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China The Wind Solar Storage Division of State Key Laboratory of Power System and Generation Equipment School of Electrical Engineering Xinjiang University Urumqi China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing China

Electrical tree is one of the major issues for insulation failure in high-voltage direct current (HVDC) cable. In this paper, electrical tree initiation and growth characteristics of silicone rubber (SIR) are studied by optical tree observation system under DC and AC voltage with varied temperature. Moreover, tree channels are pictured and analyzed by 3D fluorescence imaging technology. Results show that the average tree initiation voltage, whether DC or AC, decreases exponentially with increasing temperature. However, the initiation voltage under positive DC voltages is much higher than that under AC voltages. AC tree growth pattern could be roughly divided into two modes: bush-like growing pattern and pine-like growing pattern, while DC trees stop growing after voltage stabilizes. 3D fluorescence tests show that DC tree branches are sparser and the channels are thinner. Based on the trap theory, mechanism of DC electrical tree in SIR is clarified. It is believed that different charge transport dynamics are the main reason for the differences in electrical tree behavior under DC and AC voltages.

关键词： Three-dimensional displays Temperature Shape HVDC transmission Conferences Fluorescence Space charge

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High resistance grounding fault feeder detection in a resonant grounding system based on transient current correlation coefficient comparison 8

High resistance grounding fault feeder detection in a resona...

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8th Renewable power generation Conference, RPG 2019

作者： Cui, Xin Wang, Bin Dong, Xinzhou Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9781839531255

Because the fault characteristics is not obvious, the high resistance grounding fault feeder selection in a resonant grounding system has always been a hot and difficult problem in the field of power system protection. To solve this problem, the expressions of the transient zero sequence current of each feeder under over-damping and under-damping conditions are obtained based on the transient equivalent circuit of high resistance grounding fault in a resonant grounding system. The correlation degree of the transient zero sequence current between any two feeders is analysed by using the correlation coefficient method, so as to realize the fault feeder selection for high resistance grounding fault. simulation results of PSCAD software show that this method is not affected by transition resistance, initial phase angle of fault, and has high accuracy and reliability. © 2019 Institution of Engineering and Technology. All rights reserved.

关键词： Damping

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Effects of temperature on creepage discharge characteristics in oil-impregnated pressboard insulation under combined AC–DC voltage

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Plasma Science and Technology 2019年第5期21卷 14-22页

作者： Fubao JIN Yuanxiang ZHOU Bin LIANG Zhongliu ZHOU Ling ZHANG Key Laboratory of Plateau Ecology and Agriculture College of Agriculture and Animal HusbandrySchool of Water Resources and Electric PowerQinghai UniversityXining 800016People's Republic of China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical EngineeringTsinghua UniversityBeijing 100084People's Republic of China

Due to the complexity of the valve side winding voltage of the converter transformer, the insulation characteristics of the oil-impregnated pressboard(OIP) of the converter transformer are different from those of the traditional AC transformer. The study on effect of temperature on the creeping discharge characteristics of OIP under combined AC–DC voltage is seriously inadequate. Therefore, this paper investigates the characteristics of OIP creepage discharge under combined AC–DC voltage and discusses the influence of temperature on creepage discharge characteristics under different temperatures from 70 °C to 110 °C. The experimental results show that the partial discharge inception voltage and flashover voltage decrease with increasing temperature. The times of low amplitude discharge(LAD) decrease and amplitude of LAD increases. Simultaneously, the times of high amplitude discharge(HAD) gradually increase at each stage of creepage discharge with higher temperature. The analysis indicates that the charge carriers easily accumulate and quickly migrate directional movement along the electric field ahead of discharging. The residual charge carriers are more easily dissipated after *** ‘hump’ region of LAD moves to the direction of higher discharge magnitude. The interval time between two continuous discharges is shortened obviously. The concentration of HAD accelerates the development of OIP insulation creepage discharge. The temperature had an accelerating effect on the development of discharge in the OIP under applying voltage.

关键词： oil-impregnated pressboard insulation combined AC-DC voltage inception voltage creepage discharge temperature flashover voltage

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Green roadmap choice for coupled system of power and urban heating: quick win or long-term strategy?

Green roadmap choice for coupled system of power and urban h...

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IEEE General Meeting power& Energy Society

作者： Yisha Lin Ying Qiao Zongxiang Lu Jin Li State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China Wind Power Technology Center State Grid Gansu Electric Power Company Lanzhou China

ISBN: (数字)9781728155081

ISBN: (纸本)9781728155098

Cleanliness of energy system requires both NO x reduction due to urgent air pollution control and CO 2 cutting due to long-term climate change pressure. In the urban heating sector, quick-win plans use to be popular that focus on the NO x reduction by replacing untreated scattered coal fired boilers to natural gas or combined heat and power generators (CHPs). Meanwhile, in the electrical sector, all these fossil fuel generators should be cut down in the long-term decarbonization process. There should be a need for coordination of short- and long-term targets, because two energy supply sectors are believed to work in a coupled way in the future. A three-layered collaborative planning model is proposed in this paper: the top layer focuses roadmap economic evaluation; the middle layer applies coupled production simulation aiming at verifying energy balance; and the bottom one checks real-time operational feasibility. Pathways are made from 2020 to 2040 based on Hebei, china. Results indicate that the pathway with quick win will have delayed construction of renewable power, resulting the slow process in emission control. The long-term strategy scheme greatly promotes the renewables for supply in both sectors, but the close operational link forces the decoupling, leading to rebound on emission and operation cost on decentralized heating for the long-term future. In conclusion, the tradeoff pathway, reducing CO 2 emission as much as possible with NO x emission controlled to acceptable level, is recommended with good performance on emission control and economy.

关键词： Cogeneration Process control Production Air pollution Generators Real-time systems Planning

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Analysis of Adaptive Re-closure in AC-DC Hybrid power System 8

Analysis of Adaptive Re-closure in AC-DC Hybrid Power System

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8th IEEE International Conference on Advanced power System Automation and Protection, APAP 2019

作者： Xie, Min Zhang, Wei Liu, Ludeng Jia, Xin Wang, Bin Dong, Xinzhou Dispatching and Controlling Center of Anhui Electric Power Company State Grid Hefei China Tsinghua University Key Lab of Control and Simulation of Power Systems and Generation Equipment China

ISBN: (纸本)9781728117225

The beat frequency characteristic of the recovery voltage of fault phase in the case of single-phase grounding transient fault happening to line with the shunt reactors is analyzed. Besides, the paper analyzes the reason of no beat frequency phenomenon of transient fault happening to line without shunt reactor. The AC power networks with metallic grounding fault and arc grounding fault are analyzed by simulation. The recovery voltage of single-phase grounding fault in AC/DC hybrid power grid is studied by PSCAD. The new problems of the adaptive re-closure in AC-DC hybrid power system are discussed. Then the follow-up ideas to solve several existing problems are also presented. © 2019 IEEE.

关键词： Electric power transmission networks

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