检索结果-内蒙古大学图书馆

8th Renewable power generation Conference (RPG 2019)

作者： Zhizhong Li Bin Wang Haigang Wang Bin Yu Min Xie Shi Chen Xinzhou Dong Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China State Grid Anhui electric power company Hefei 230061 China

ISBN: (数字)9781839531248

ISBN: (纸本)9781839531255

The lack of analytical mechanism of continuous commutation failure (CCF) process hinders the development of CCF early warning algorithm and further obstructs the coordination strategy of relay protection between AC and DC size in hybrid grid. However, summarizing the protection threshold of CCF in the form of electrical quantity analytically under different fault types is a nontrivial pattern recognition problem. To overcome the difficulty of directly analysing the electromagnetic process of CCF, a statistical learning modelling approach is adapted to propose a CCF warning system, in which XGBoost algorithm was used as the backbone to regress on the relationship between AC/DC electrical quantities and the possibility of the occurrence of CCF. The design of the feature vector in XGBoost-based classifier considers not only the analytical expression of key electrical quantity during single commutation failure but also the important state variable of control system. Additionally, a special data windowing method was proposed to enrich of information encoded by the feature vector while ensuring the speed requirement posed by the protection system. Validation on multi-fault scenes simulation shows that the proposed early warning system can trigger warning signal correctly with sufficiently small measured data required, proving the practicability in engineering practice.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Optimization of Operation Strategy of Virtual power Plants Involved in Peak Shaving

Optimization of Operation Strategy of Virtual Power Plants I...

引用

China International Electrical and Energy Conference (CIEEC)

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

ISBN: (数字)9781728116754

ISBN: (纸本)9781728116761

In recent years, as the consumption rate of renewable energy has increased, the impact of renewable energy on the power grid has also increased. Currently, distribution network system operators and transmission line system operators are unable to acquire and control the operational status of renewable energy sources such as wind power photovoltaics. These phenomena pose a significant challenge to the safety and stability of the operation of the power system. The virtual power plant is a feasible solution, based on the data acquisition terminal of advanced communication technology, decentralized control or centralized control of DER. Based on the virtual power plant, this paper aggregates three types of resources, wind power, photovoltaic, and electric vehicles, which are typical on the supply side and the demand side. Then, the virtual power plant is regarded as a whole to accept the dispatching instructions of the power grid, formulate the operational strategy of the internal resources of the virtual power plant, and participate in the peaking service.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Charge Evolution and Dielectric Property of Three-phase Polypropylene Composites With Enhanced Mechanical Performance

Charge Evolution and Dielectric Property of Three-phase Poly...

引用

中国物理学会第二十二届全国静电学术年会

作者： Ling Zhang Zhaowei Peng Yuanxiang Zhou Zekai Lu Yonggang Guan Zixia Cheng State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department School of Electrical Engineering Zhengzhou UniversityZhengzhou 450001China

High voltage DC(HVDC)power cable technology has the advantages of large transmission capacity,low loss,negligible electromagnetic environmental effect,and trackless corridor,etc.,which make it capable to solve the significant problem of power transmission channels during the fast development of electric ***,it also contributes to eco-friendly,resource-saving,safe,and reliable goal of power transmission *** to common crosslinked polyethylene materials,isotactic polypropylene(iPP)has the advantages of non-crosslinking,high-temperature-resistant,recyclable,low production cost,and free maintenance work,and has been a hot spot in the research field of high performance HVDC cable insulating ***,iPP is a thermoplastic limited by its impact strength,especially at low temperatures,because of its high degree of crystallinity and high glass transition *** of the common methods used to increase the impact strength is the addition of low-molecular elastomer materials or nucleating agents(NAs)into the iPP matrix,which is blended with the polymer in the molten *** previous investigations with the binary blending system have demonstrated that improved impact resistance usually was accompanied by decreasing the stiffness or deteriorating its original electrical properties in some *** order to achieve an optimum balance of macroscopic properties,adding several components is often necessary in polymer *** aim of this work is to investigate the synergistic effects on mechanical and electrical properties between NAs and different elastomers in iPP *** have shown that increasing the β-crystal content can improve its electrical property and elastomer can strengthen its mechanical performance.,Thus,three-phase iPP blends(iPP-β-x,x refers to the elastomer)were prepared with the incorporation of arylamide derivative β-NAs(TMB-5,0.2 wt%)and different elastomers(15 wt%)including styrene-bethylene butylene-b-styr

关键词： isotactic polypropylene β nucleating agent elastomer impact strength space charge

来源：评论

学校读者我要写书评

暂无评论

Transient Behaviors of Space Charge in Low-density Polyethylene Films at Prebreakdown Under Temperature Fields

Transient Behaviors of Space Charge in Low-density Polyethyl...

引用

中国物理学会第二十二届全国静电学术年会

作者： Ling Zhang Zekai Lu Yuanxiang Zhou Zhaowei Peng Zixia Cheng Yonggang Guan State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department School of Electrical Engineering Zhengzhou UniversityZhengzhou 450001China

Currently,insulation performance of high voltage DC(HVDC)power cables is still of critical significance challenge in both engineering application and fundamental *** example,HVDC cable insulation suffers breakdown under the conditions of cold start and load cycling tests,and the presence of space charge at high temperatures causes electric field distortion within the ***,the operating temperature of HVDC cables could only reach 70℃at *** work intends to carry out research on the effect of temperature on space charge characteristics of low-density polyethylene(LDPE)films at prebreakdown under a linearly ramping voltage,which is of great significance for further understanding and improving the operating temperature and breakdown strength of HVDC ***-free LDPE film with a thickness of 100 μm was purchased from GoodFellow *** improved space charge measurement system was developed with a high-speed measurement interval of 1 ms,a high voltage pulse of 120 V,and a pulse width of 5 ns.A linearly ramping voltage of 0.5 kV/s was selected and cut off after breakdown *** and steady behaviors of space charge was comprehensively sudied under a linearly ramping voltage of 500 V/s at 30℃and 70℃,*** results show that negative charge was rapidly injected and accumulated near the anode at a relatively low electric field at 70℃.As the applied electric field gradually increased,the anode appeared a significant positive charge *** phenomenon occurred when charge packets were injected to a certain distance of~30 μ*** the contrast,there was only negative charge injection and accumulation in the bulk of LDPE films at 30℃,and breakdown was not observed even when the voltage rose to-30 *** was found that the anode had a positive space charge packet injection at 30℃and slowly migrated to the cathode,and the entire transit process took tens of *** the internal electric field distribution,the ma

关键词： LDPE prebreakdown transient space charge internal field distortion carrier mobility

来源：评论

学校读者我要写书评

暂无评论

Research on inter-turn short circuit of armature windings in the multiphase synchronous generator-rectifier system

Research on inter-turn short circuit of armature windings in...

引用

作者： Sun, Yuguang Wang, Shanming Huang, Ziguo Mu, Shujun State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China

The multiphase synchronous generator-rectifier system could provide an ideal DC power source for more electric aircraft (MEA). When the inter-turn short-circuit fault occurs in phase windings of the generator, a large short-circuit current would be introduced inside the armature windings, which could cause severe damages to the system for overheat in the windings and irons as well as huge electromagnetic forces on the end coils. To improve the reliability of the MEA, this study researches on the inter-turn fault of the multiphase generator-rectifier system, including the theoretical analysis, numerical simulation and experimental verification. A 12-phase system is taken for example, and a multi-loop mathematical model is built up to calculate all voltages and currents in the multiphase synchronous generator-rectifier system with armature inter-turn fault. Many factors are thoroughly considered in the model, including the location and short-turns of fault, space harmonics of air-gap magnetic field and the changing circuit topology of the system. The mathematical model is verified by fault experiment results. Moreover, the electric characteristics of the fault are summarised, which could provide a quantitative basis for early detection of the inter-turn faults in the multiphase generator-rectifier system. © 2018 Institution of Engineering and Technology. All rights reserved.

关键词： More electric aircraft

来源：评论

学校读者我要写书评

暂无评论

Minkowski Sum Based Flexibility Aggregating Method of Load Dispatching for Heat Pumps

引用

Dianli Xitong Zidonghua/Automation of Electric power systems 2019年第5期43卷 14-21页

作者： Li, Zihao Li, Tie Wu, Wenchuan Zhang, Boming Jiang, Feng Cui, Dai Department of Electrical Engineering Tsinghua University Beijing100084 China State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing100084 China State Grid Liaoning Electric Power Supply Company Shenyang110006 China

With the implementation of the "coal to electricity" project, the heat pump load in the distribution network increases significantly. Standing in the point of heat pump users, cooperative game mode is used for heat pumps joining in day-ahead dispatching of distribution network. In order to accurately describe the polymerization flexibility of the heat pump load cluster, this paper uses the constraint space superposition method based on Minkowski Sum, and describes the heat pump cluster as a "virtual synchronous machine" or "virtual energy storage" model by looking for its maximal inner cube or rectangular pyramid simplification constraint. Furthermore, a method of income distribution among users based on approximated Shapley Value is proposed. The validity of the proposed method is verified by the case based on IEEE 33 mode system. © 2019 Automation of Electric power systems Press.

关键词： Game theory

来源：评论

学校读者我要写书评

暂无评论

Study on High Impedance Grounding Fault Protection for Personal Safety Guard in Distribution Grid

Study on High Impedance Grounding Fault Protection for Perso...

引用

International Conference on Advanced power System Automation and Protection (APAP)

作者： Kun Liu Xin Cui Bin Wang Xinzhou Dong Dispatching and Controlling Center of Guangdong Power Grid Key Lab for Power System Protective Relaying Real Time Digital Simulation of Guangdong Power Grid Guangzhou China Tsinghua University Key Lab of Control and Simulation of Power Systems and Generation Equipment Beijing China

ISBN: (数字)9781728117225

ISBN: (纸本)9781728117232

In recent years, human electric shock accident caused by line fault of distribution system has happened all over the world. This kind of problem of high resistance grounding fault safety is becoming more and more the attention of the researchers. In this paper, typical arc high resistance grounding fault model is established to simulate the human electric shock accident and the line fell to the ground condition. The transient- state and steady-state fault characteristics of high resistance grounding fault are analyzed in the neutral point grounded through a small resistance grounding system and the resonant grounding system. The above analysis has laid a good foundation for the establishment of an effective fault detection method for high resistance grounding and the realization of human electric shock protection.

关键词： Grounding Immune system Resistance Harmonic analysis Transient analysis Electric shock Steady-state

来源：评论

学校读者我要写书评

暂无评论

Coordinated Wholesale and Retail Market Mechanism for Providing Demand-side Flexibility

Coordinated Wholesale and Retail Market Mechanism for Provid...

引用

Sustainable power and Energy Conference (iSPEC)

作者： Gang Luo Yujun He Chen Zhao Xuan Zhang Shaohua Lin Yue Zhao Dispatch and Control Center Guangdong Power Grid Co. Ltd Guangzhou China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China

With the trend of electricity market deregulation for recent decades, the consumers at demand-side are progressively encouraged to trade the power in competitive market environment. Conventionally, only large-scale consumers participate directly in the wholesale market that adopts spot energy pricing. Most small-scale consumers are involved in the retail market that offers non-varying tariff predefined by retailers or utility companies. In this work, we investigate a framework of coordinated wholesale and retail market structure that enables consumers in the retail market to reflect the spot price and improve the power system flexibility for the high penetration of renewables. Then, market behaviors of demand-side participants with the proposed market mechanism and some related business models are discussed. The following participation modes for consumers could be opted including: direct trade, trade agented by retailers or organized in virtual power plant (VPP). For a pool-based trade at demand-side, a bi-level market clearing mechanism at transmission and distribution levels is explained. This mechanism seeks to optimize the global demand profile for hosting renewables while solving the operating constraint of loads and local networks. This study can offer constructive advises to promote further development of China's electricity market.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Vulnerability Assessment Based on Operational Reliability Weighted and Preventive Planning

Vulnerability Assessment Based on Operational Reliability We...

引用

Sustainable power and Energy Conference (iSPEC)

作者： Ning Qi Lin Cheng Yi Jiang Jinshan Luo Ke Sun Dan Wang Weiyuan Wang Wentao Sun State Key Lab. of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China State Grid Jiangsu Economic Research Institute Jiangsu China

Vulnerability assessment is the key to the security and stability analysis of power system. During the operation of power grid, the fault risk of electrical equipment is not fixed because of the influence of system operating conditions, operating environment and equipment itself, so the vulnerability of power system will also be changeable. Based on the existing research results of complex network theory, a vulnerability assessment method considering operational reliability is proposed in this paper. Firstly, the basic idea of reliability weighted vulnerability assessment is introduced. Then HITS algorithm and PageRank algorithm will be used to analyze the basic vulnerability of power grid topology. Moreover, the vulnerability index of power grid considering reliability weighted is calculated. Finally, numerical analysis focusing on the difference between basic and improved assessment method is tested in IEEE RTS-79 system, and the preventive planning suggestions will be given based on the vulnerability assessment results.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Carbon Wrapped Rutile TiO2 Nanoparticles for Dinitrogen Electroreduction to Ammonia at Ambient Conditions

Carbon Wrapped Rutile TiO2 Nanoparticles for Dinitrogen Elec...

引用

中国化学会2019能源材料和缺陷化学研讨会

作者： Xiaoyang Cui Xiao-meng Liu Shao-xin Wei Yi-ming Cui Ling Zhang Qiang Zhang Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical Engineering Tsinghua University State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University

Catalytic conversion of dinitrogen（N） into ammonia under ambient conditions represents one of the Holy Grails in sustainable chemistry. As a potential alternative to the Haber-Bosch process, electroreduction of N to NH is attractive owing to its renewability, sustainability and flexibility. However, electrocatalysts with high catalytic activity and high selectivity are rare because of the kinetically complex and energetically challenging N reduction reaction（NRR） process. In particular, the competing hydrogen evolution reaction（HER） is crucial for the low selectivity.

关键词： TiO Carbon Wrapped Rutile TiO2 Nanoparticles for Dinitrogen Electroreduction to Ammonia at Ambient Conditions

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：