检索结果-内蒙古大学图书馆

2022 IEEE International Conference on High Voltage engineering and Applications, ICHVE 2022

作者： Liang, Fangwei Zhuang, Weijian Liang, Zuodong Zhang, Bo Li, Chuanyang He, Jinliang Wang, Feng Chen, She Tang, Lingling Zeng, Yulin Tsinghua University State Key Laboratory of Power System Department of Electrical Engineering Beijing100084 China College of Electrical and Information Engineering Hunan University Changsha410082 China Jiangsu Jinxin Electric Appliance Co. Ltd Jiangsu China

ISBN: (数字)9781665407502

ISBN: (纸本)9781665407502

Surface charge accumulation has been a long-existed issue hindering the development of insulators in gas-insulated equipment. However, the mechanism is still not clear. In this paper, the surface potential distribution before and after X-ray irradiation is analyzed, and a surface charge transport model is established. The effects of the generation rate of ion pairs and the applied voltage on the surface charge are studied. The results show that a large number of positive charges accumulate on the insulator surface after X-ray radiation. Surface charges cannot be dissipated by X-rays under online condition. Under offline condition, the conduction current in gas becomes the dominate pathway of surface charge dissipation. Since X-rays can promote the ionization of SF6, the charged particles generated by the ionization recombine with the hetero-polar surface charges. Therefore, the surface charge can be dissipated quickly. Under the applied voltage, ions of opposite polarity in gas migrate to the insulator surface. As a result, positive charges accumulate on the spacer surface. To conclude, X-rays are only suggested as a tool for surface charge dissipation under offline operation. © 2022 IEEE.

关键词： Surface potential

来源：评论

学校读者我要写书评

暂无评论

New-Type power system Stabilizers (NPSS) for Damping Wideband Oscillations in Converter-Dominated power systems

引用

CSEE Journal of power and Energy systems 2023年第3期11卷 1186-1198页

作者： Jan Shair Xiaorong Xie Haozhi Li Vladimir Terzija Department of Electrical Engineering State Key Laboratory of Power System Tsinghua University Beijing China Center for Energy Science and Technology Skolkovo Institute of Science and Technology Moscow Russia

Traditionally, synchronous generators are equipped with power system stabilizers (PSSs) to stabilize electromechanical low-frequency oscillations (LFOs). With increasing applications of converter-based devices in modern power systems, system-wide control interactions between different converter-based devices are causing more prevalent electromagnetic wide-band oscillations (WBOs). Extensive research has been done on design, application, and standardization of classical PSSs for addressing LFOs associated with synchronous generators. However, little attention is given to same for converter-based devices as a countermeasure to electromagnetic WBOs. This paper proposes a concept of utilizing new-type power system stabilizers (NPSSs) specifically designed to address WBOs caused by converter-control interactions in modern converter-dominated power systems. The article puts forward various design strategies, tuning methods, and implementation techniques of the NPSSs to counteract WBOs. The NPSSs are not limited to inverter-based resources (type-3/4 wind turbines); they can also be applied to other converter-based devices such as FACTS controllers, HVDC links, battery storage inverters, etc. We present several application scenarios demonstrating the importance of supplementing NPSSs in converter-based devices. Furthermore, the paper highlights current research challenges and opportunities in designing and implementing NPSS for various converter-based devices, providing a comprehensive overview of state-of-the-art and future directions in this area.

关键词： Oscillators power system stability Damping power system dynamics Frequency control Filtering theory Electromagnetics

来源：评论

学校读者我要写书评

暂无评论

SiC MOSFET Crosstalk Modelling with Suppression Considering Impacts of dv/dt and di/dt

SiC MOSFET Crosstalk Modelling with Suppression Considering ...

引用

International Conference on power Electronics (ICPE)

作者： Wenhao Xie Shiqi Ji Zhengming Zhao Xin Mo Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University China Tsinghua Sichuan Energy Internet Research Institute China

Compared to Si IGBTs, SiC MOSFETs can reduce switching losses, achieve higher switching frequencies and enable smaller converter size. However, due to the high dv/dt of SiC MOSFETs, certain topologies, such as two SiC MOSFETs in a phase-leg configuration, are highly sensitive to crosstalk, which can slow down switching speed and even reduce gate oxide’s lifetime. In this paper, an accurate model of crosstalk is established by considering the impacts of both dv/dt and di/dt in the power loop. The proposed model can simulate the gate-source voltage on bare die of SiC MOSFETs, allowing for a more accurate evaluation of the impact of crosstalk. Model verification is implemented using a double pulse test (DPT) platform and a gate driver with active miller clamp technology. key parameters of the model are extracted from both 3D simulation models and measurement experiments. The DPT waveform of power loop is used as the excitation source in the simulation, and the simulated gate-source waveform shows good agreement with the experimental waveform. Based on the model, parameter sensitivity analysis is performed, and suggestions for improving crosstalk suppression are proposed.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Effect of carbon black contents on polypropylene-based semi-conductive shielding materials for power cables

Effect of carbon black contents on polypropylene-based semi-...

引用

Tsinghua University-IET electrical engineering Academic Forum 2024

作者： Cheng Tong Xiyu Zhang Shangshi Huang Si Qin Chi Yao Yong Liang Qi Li Jinliang He Yonggui Zhao Jianjian Xu School of Electrical Engineering Guangxi University Nanning Guangxi People's Republic of China State Key Laboratory of Power System Operation and Control Department of Electrical Engineering Tsinghua University Beijing People's Republic of China HJ Polymer China Co. Ltd Jiangyin Jiangsu People's Republic of China State Grid Linyi Power Company Linyi Shandong People's Republic of China

ISBN: (数字)9781837242139

Polypropylene-based semi-conductive shielding materials have emerged as significant areas of research in recent years. This paper has investigated the influence of carbon black contents on the properties of semi-conductive composites. Four specimens have been prepared that impact-resistant polypropylene as the matrix and conductive carbon black as the filler with varying carbon black mass fractions (10%, 20%, 30%, and 40%). The properties of semi-conductive composites have been evaluated including thermal, microstructural, mechanical, and electrical. The findings indicate that carbon black contents significantly influence the mechanical and electrical properties, while its effect on thermal properties are less pronounced. Overall, the semi-conductive composites exhibit optimal properties when the carbon black mass fraction is 30%.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Performance evolution of NI-YSZ anode-supported Sofcs during initial-stage operation 17

Performance evolution of NI-YSZ anode-supported Sofcs during...

引用

17th International Symposium on Solid Oxide Fuel Cells, SOFC 2021

作者： Lyu, Zewei Han, Minfang Department of Energy and Power Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing100084 China

ISBN: (纸本)9781607685395

Performance evolution of typical Ni-YSZ anode-supported SOFCs during the initial-stage operation ( 20 h), regardless of the operating current. In the activation stage, the cell performance maintains stable or slightly increases due to the enhanced anode gas-phase diffusion. While in the subsequent aging stage, the cell performance decreases significantly and gradually approaches a plateau in about 100 hours, mainly due to the weakened anode charge transfer reaction and ionic transport processes. Therefore, it is suggested that more efforts should be focused on improving the stability of anode microstructure, especially the stability of anode functional layer. © 2021 Electrochemical Society Inc.. All rights reserved.

关键词： Chemical activation

来源：评论

学校读者我要写书评

暂无评论

Optimal operation of Flexible Interconnected Distribution Networks

Optimal Operation of Flexible Interconnected Distribution Ne...

引用

2021 International Conference on Advanced electrical Equipment and Reliable operation, AEERO 2021

作者： Qi, Qi Xie, Hongbin Qi, Buyang Xu, Yanping Li, Pai China Electric Power Research Institute State Key Laboratory of Operation and Control of Renewable Energy Storage Systems Beijing China Tsinghua University Department of Electrical Engineering Beijing China

ISBN: (纸本)9781665402644

With large-scale distributed generation (DG) being integrated into distribution networks, the idea of using power electronic devices to improve distribution network operation have attracted increasing attentions. The transition of distribution networks into flexible interconnected ones, which contain considerable penetrations of AC/DC converters and soft open points (SOPs) is foreseen. In this paper, an optimization framework to improve the operation of the new form of distribution networks is proposed, where a novel searching technique is developed to determine the optimal set-points of the power electronic devices with increased efficiency. A generic power flow algorithm considering different modes of the controllable devices is presented, where the power flow problem is formulated into a set of nonlinear equations, and a globally convergent Newton-trust region method is adopted to solve it. Results of the case study demonstrate the feasibility and efficiency of the proposed method. © 2021 IEEE.

关键词： Distributed power generation

来源：评论

学校读者我要写书评

暂无评论

Co-optimizing electric bus dispatching and charging considering limited resources and battery degradation

引用

Multimodal Transportation 2024年第4期3卷

作者： Niu, Chenming Chen, Qiuzi Tu, Ran Huang, Di Ye, Yujian School of Transportation Southeast University China Department of Civil and Environmental Engineering University of California Berkeley United States Key Laboratory of Transport Industry of Comprehensive Transportation Theory (Nanjing Modern Multimodal Transportation Laboratory) Ministry of Transport China School of Electrical Engineering Southeast University China State Key Laboratory of Power System Operation and Control Department of Electrical Engineering Tsinghua University China

This paper aims to formulate a mathematical model for a multi-type electric bus scheduling problem to determine the optimal fleet composition, bus-to-trip assignment, and partial charging schedule, where the battery degradation, nonlinear charging, and the constraint of charging station capacity are considered. A time-expanded network is proposed to represent the bus-to-trip assignment and partial charging. An adaptive large neighborhood search algorithm is designed to solve the problem. Using a multi-line bus network in Nanjing as the case, empirical operational data is used to generate monthly timetable samples to simulate the uncertainty of trip travel time and energy consumption. The result shows that the charging station capacity can be reduced from 20 (real-world case) to 12, considering the cost-effectiveness and robustness of the bus system. The result of this study also provides suggestions on the charging duration choices and the starting state-of-charge for different periods of the day. In peak and off-peak hours, 20-30-minute charging is recommended for electric buses with state-of-charge lower than 30 %, and 10-minute charging is more recommended when the state-of-charge of the electric bus is between 30 % and 70 %. © 2024 The Author(s)

关键词： Battery degradation Bus-to-trip assignment Energy consumption uncertainty Fleet composition Partial charging schedule

来源：评论

学校读者我要写书评

暂无评论

Optimization of methane reforming for high efficiency and stable operation of SOFC stacks 17

Optimization of methane reforming for high efficiency and st...

引用

17th International Symposium on Solid Oxide Fuel Cells, SOFC 2021

作者： Liu, Yaodong Lyu, Zewei Han, Minfang Department of Energy and Power Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing100084 China

ISBN: (纸本)9781607685395

Solid Oxide Fuel Cells (SOFCs) provides an efficient and clean pathway to generate electricity. In addition to hydrogen, SOFCs also hold the possibility for the utilization of a variety of carbon containing fuels. A practical kilowatt-class SOFC system fueled by methane has been preliminarily integrated previously. This study intended to obtain the optimized working conditions for the prereformer, with which the SOFC module can exhibit higher electrical performance. Detailed thermodynamic analysis and experimental measurements of steam methane reforming (SMR) were carried out under different steam to carbon ratios (S/C) and temperatures, where the experimental results matched well with the thermodynamic calculation. Based on the optimized working condition of SMR, the electrical performance and stability of a planar single-layer stack (10×10 cm2) fueled by the reformate syngas was evaluated. The maximum electrical efficiency reached 65.39% (LHV) at 750 C, and 50-hour stable operation under 50% (LHV) electrical efficiency was achieved. © 2021 Electrochemical Society Inc.. All rights reserved.

关键词： electrical efficiency

来源：评论

学校读者我要写书评

暂无评论

Improvement of the electrical Properties of Silicone Rubber Doped with Nano-zirconia Grafted by Voltage Stabilizer

Improvement of the Electrical Properties of Silicone Rubber ...

引用

International Conference on electrical Materials and power Equipment (ICEMPE)

作者： Xiaoqian Zhu Yuanxiang Zhou Yunxiao Zhang Ming Chen Xuanhao Liu State Key Lab of Control and Simulation of Power System and Generation Equipment & Department of Electrical Engineering Tsinghua University Beijing China College of Electrical Engineering and Automation Fuzhou University Fuzhou China Xiamen Power Supply Company State Grid Fujian Electric Power Company Xiamen China The Wind Solar Storage Division of State Key Laboratory of Control and Simulation of Power System and Generation Equipment School of Electrical Engineering Xinjiang University Urumqi China

Enhancing the electrical performance of silicone rubber (SiR) for cable accessories is noteworthy as they are almost the weakest parts of the cable system. Two types of voltage stabilizers were grafted onto the surface of nano-zirconia (ZrO 2 ) particles, and the grafted nanoparticles were added to the SiR. Measurements such as breakdown strength, and conductivity were carried out to evaluate the electrical performance of SiR nanocomposites. The electrical performance measurement results indicated that the breakdown strength of the nanocomposite SiR improved while the conductance current was reduced. The trap distribution showed that the improvement of the electrical performance of the nanocomposite SiR is mainly due to the decrease of the shallow trap density or the increase of the deep trap density.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Review of Live Measurement for power Frequency Parameters of Transmission Lines

Review of Live Measurement for Power Frequency Parameters of...

引用

IEEE International Conference on power and power and Renewable Energy (ICPRE)

作者： Zhenqiang Li Zhengwei Sun Zhijian Hu Kai Fan Pengfei Tian Jun Luo State Key Laboratory of Power Grid Environmental Protection China Electric Power Research Institute Wuhan China Power system operation scheduling Northeast Branch of State Grid Corporation of China Shenyang China School of Electrical Engineering and Automation Wuhan University Wuhan China Power system operation scheduling State Grid Liaoning Electric Power Co. LTD Shenyang China Technical section Shandong Dashun Electronic Technology Co. Ltd Jinan China

ISBN: (数字)9798350377460

ISBN: (纸本)9798350377477

The live measurement of line parameters (LMLPs) has great application prospects. However, up to now, the application of LMLPs in engineering is very rare. In view of this problem, the paper analyzes the influencing factors of the accuracy of LMLPs, and puts forward that the error of measuring small signal by VT and CT should be paid attention to. The signal increment method and non-power frequency method are the two main methods for LMLPs. Combined with the non-power frequency method, signal increment method can further resist strong electromagnetic interference and improve the measurement accuracy. It is feasible to generate large zero sequence signals by operatng the single-phase circuit breaker on line, and there is no overvoltage and safety risk. Finally, the problems to be solved in the popularization and application of LMLPs are summarized: improving the power of the test power supply, miniaturization and light weight; clarifying the small signal measurement accuracy of VT and CT, and quantifying the system error of LMLPs. The corresponding suggestions are given, which provides a technical reference for the popularization and application of live line parameter measurement.

关键词： Weight measurement power measurement Accuracy Reviews Measurement uncertainty Energy measurement Transmission line measurements Frequency measurement Safety Voltage control

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：