检索结果-内蒙古大学图书馆

26th International Congress on Sound and Vibration, ICSV 2019

作者： Yang, Yizhou Liu, Chao Jiang, Dongxiang Han, Te State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9781999181000

The inter-shaft bearing could simplify the supporting structure of a dual-rotor system, so it is widely used in rotating machinery like gas turbine engine. When monitoring the vibration of an inter-shaft bearing, sensors usually could not be installed inside the engine because of the compact structure, then will be installed on the casing. The vibration of the inter-shaft bearing will be transmitted though both the two rotors to the supporting bearings then to the casing, and both the inner and outer ring rotate, making the condition monitoring much more difficult than normal bearings. In this paper, a dual-rotor system dynamic model with the rotor-bearing-casing structure is built to simulate the vibration of an inter-shaft bearing. The rotors and the casing are modelled using finite element method and the bearings are modelled using a nonlinear multi-body dynamic model. The normal state of the inter-shaft bearing is simulated, then the bearing fault states with localized defects on the inner race, the outer race and one of the rolling elements are simulated. Signal processing methods are utilized to extract bearing fault features from the casing vibration acceleration signal. Besides the fixed rotating speed condition, rotors under variable speeds are also simulated, then the vibration signal and fault feature become more complex and the signal analysis becomes a bigger challenge © Proceedings of the 26th International Congress on Sound and Vibration, ICSV 2019. All rights reserved.

关键词： Dynamic models

来源：评论

学校读者我要写书评

暂无评论

Reactive voltage control of bidirectional-interaction coordination between provincial and district power networks with wind power integration

引用

Dianli Xitong Zidonghua/Automation of Electric power systems 2014年第24期38卷 48-55页

作者： Wang, Bin Guo, Qinglai Li, Haifeng Sun, Hongbin Tang, Lei Zhang, Boming State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing100084 China Department of Electrical Engineering Tsinghua University Beijing100084 China

An agile and coordinated voltage control method is proposed to deal with the power system reactive power and voltage operation with large scale wind power integration. In the provincial control center, the agile voltage control method with the wind power volatility and the power system N-1 security constraints taken into account is proposed. With this method, by means of the adaptive adjustment of the control period and control model, the wind farm reactive ability will be fully tapped to suppress the influence of wind fluctuations on the bus voltage while sufficient dynamic reactive power regulation margin of traditional generators will be retained. Between provincial and prefectural control centers, the bidirectional interaction based voltage control method is presented to support the voltage at the terminal power network while bypassing the unnecessary discrete device action on the prefectural grid. By coordinated voltage control among the wind farms and substations in the provincial power system, the control abilities of its own wind farms will be made full use of, there will be less capacitor and reactor action times in its own substations and unnecessary reactive power flow. By the bidirectional interaction between provincial and prefectural control centers, the distributed adjustment resources can well be used to support the voltage at the terminal power network and increase the safety and economy of overall operation of the power system. The wind automatic voltage control system is currently in real-time operation in Jiangsu power system. © 2014 state Grid Electric power Research Institute Press.

关键词： Voltage control

来源：评论

学校读者我要写书评

暂无评论

Condition Evaluation of power Cables Based on BiLSTM with Siamese Attention

Condition Evaluation of Power Cables Based on BiLSTM with Si...

引用

2023 Panda Forum on power and Energy, PandaFPE 2023

作者： Lin, Menglong Chen, Jianning Zhou, Yuanxiang Pan, Zehua Tsinghua University State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Beijing China Beijing Electric Power Research Institute State Grid Beijing China

ISBN: (纸本)9798350321173

The fast and accurate state evaluation of cable plays an important role in the safe and reliable operation of power system. Thus a high-voltage cables condition evaluation model based on siamese-attention bidirectional long short-term memory (SA-BiLSTM) is proposed in this paper. First, the attention mechanism was used to optimize the BiLSTM network, which can complete parallel training while obtaining global information. then the optimized network was adopted to build a siamese neural network framework, realizing data classification by calculating the Euclidean distance between feature vectors. Finally, the model was trained and tested through the online monitoring data of high-voltage cables from engineering. The results showed that the accuracy rate, precision, recall rate, F1 score and Matthews correlation coefficient of the SA-BiLSTM model was increased at least by 7.92%, 11.79%, 11.41%, 12.04%, and 20.90%, respectively, compared with other models. © 2023 IEEE.

关键词： Long short-term memory

来源：评论

学校读者我要写书评

暂无评论

Grid dispatch model and interconnection benefit analysis of concentrating solar power plants with thermal storage

引用

Dianli Xitong Zidonghua/Automation of Electric power systems 2014年第19期38卷 1-7页

作者： Chen, Runze Sun, Hongbin Li, Zhengshuo Liu, Yibing Department of Electrical Engineering Tsinghua University Beijing100084 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing100084 China

Nowadays, the concentrating solar power (CSP) plant with thermal storage is a new way to utilize solar power. By making full use of large-capacity CSP devices, the CSP system is able to translate the solar power absorbed. Additionally, the CSP generates power via a steam turbo-generator and has fast regulating performance. The operation behavior of CSP is studied from the viewpoint of power grid, based on which its mathematical model for dispatch is developed. The model describes the power flow inside the CSP with its major operation constraints. Furthermore, the model for power system dispatch considering CSP plants is built based on the security-constrained unit commitment problem. It is shown by simulation that CSP, on the premise of its energy being fully accommodated, may bring about considerable benefits to the power system by reducing the generation cost, increasing renewable energy accommodation and enhancing utilization of transmission lines. © 2014 state Grid Electric power Research Institute Press.

关键词： Concentrated solar power

来源：评论

学校读者我要写书评

暂无评论

Optimal Sizing of Photovoltaic and Battery Energy Storage of Electric Vehicle Charging Station Based on Two-part Electricity Pricing

Optimal Sizing of Photovoltaic and Battery Energy Storage of...

引用

2020 IEEE Sustainable power and Energy Conference, iSPEC 2020

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

ISBN: (纸本)9781728191645

This paper focuses on optimal sizing of photovoltaic (PV) and battery energy storage system (BESS) of special-use charging station for electric taxi cabs. Aiming to minimize annual equivalent cost of the charging station under two-part electricity pricing mechanism, an optimal sizing algorithm of PV and BESS is established considering the randomness of PV output and the power constraint of the grid, as well as whether charging station participates in demand response (DR). The cooperative operation strategies of charging facilities, PV and BESS under typical scenarios are proposed. Considering the factors that affect the optimal results, this paper provides sensitivity analysis in a charging station. Finally, the proposed optimal sizing algorithm is verified in the charging station equipped with 24 EV charging piles, and the economic analysis of the optimal sizing scheme is carried out. Based on economical analysis of optimal sizing results, it is found out that the equivalent cost of EV charging station is lower when participating in demand response. The results show that the annual equivalent total cost of the charging station is significantly reduced under the new optimal sizing scheme. © 2020 IEEE.

关键词： Sensitivity analysis

来源：评论

学校读者我要写书评

暂无评论

Mathematical expectation modeling of wide-area controlled power systems with stochastic time delay

Mathematical expectation modeling of wide-area controlled po...

引用

IEEE General Meeting power& Energy Society

作者： Chao Lu Xinran Zhang Xiaoyu Wang Yingduo Han State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University

ISBN: (纸本)9781467380416

Summary form only given: Communication network brings new challenges such as time delay and data loss to wide-area damping control of power systems. The uncertainty caused by stochastic time delay of network communication increases the difficulty of wide-area control performance analysis. This paper proposes a mathematical expectation modeling approach to model and analyze wide-area controlled power systems considering the effect of stochastic time delay. In the proposed method, mathematical expectation of stochastic time delay distribution is derived to accurately model the impact of communication network on wide-area control performance. The theoretical frame of the proposed modeling approach is presented and the effectiveness of the method is verified through the simulation of a power system with 8 generators and 36 nodes.

关键词： Mathematical model power systems Delay effects Stochastic processes control systems Data models Communication networks

来源：评论

学校读者我要写书评

暂无评论

Surface Partial Discharge Characteristics of Oil-paper Insulation Under Combined AC-DC Voltage

引用

高电压技术 2013年第8期39卷 1902-1910页

作者： SHA Yanchao ZHOU Yuanxiang NIE Dexin WU Zhirong DENG Jiangang LU Licheng State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China State Key Laboratory of Electrical Insulation and Power Equipment Department of Electrical Engineering State Grid Electric Power Research Institute Wuhan 467001 China State Grid Corporation of China Beijing 100031 China

The valve side windings of converter transformers bear AC, DC, impulse, and reversal-polarity voltages during operation, which could result in serious insulation problems of the equipment. By performing experiments with surface discharge model of oil-paper insula- tion at 80 ℃ under combined AC-DC voltage for 200 h, we studied the spectrums and statistical parameters of partial discharges at different discharge stages. Furthermore, some fingerprint parameters were calculated in order to estimate the development situation of par- tial discharge, while the characteristic gases dissolved in the transformer oil were measured by gas chromatography. The surface discharges in the experiments were observed using a high speed camera, and a full discharge process could be marked off into four stages as follows. ①The elementary stage. When a partial discharge occurs near electrodes, electrical charges are injected into the region near electrodes and causing bubble generation. ②Due to their high resistivity and low dielectric constant, the bubbles would bare the major part of the voltage applied to samples. Therefore, discharge happens inside the small bubbles, and it emits a lot of light. ③Micromolecules of gas are produced in discharge, and further ionization in the transformer oil takes place simultaneously when high-energy electrons collide with oil molecules. ④The carrier charge moves forward to electrodes driven by the applied electric field, till they neutralize with the charge from electrodes, and hence discharge channels are formed subsequently.

关键词： AC-DC 放电特性绝缘表面电压油纸油中溶解气体换流变压器合作

来源：评论

学校读者我要写书评

暂无评论

Breakdown phenomena caused by electrical tree degradation in high density polyethylene under high frequency voltage

引用

Gaodianya Jishu/High Voltage Engineering 2007年第12期33卷 14-18页

作者： Zhou, Yuan-Xiang Xing, Xiao-Liang Nie, Qiong Wang, Yun-Shan Wang, Ning-Hua Liang, Xi-Dong Guan, Zhi-Cheng State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China

The shape change of electrical tree propagating in ice-water quenched high-density polyethylene (HDPE) film under AC voltage of different frequency ranging from 50 Hz to 90 kHz as well as the breakdown phenomena caused by the treeing degradation under high frequency condition were studied. The electrical treeing aging experiment is carried out at room temperature. The shape change of electrical tree and the arcing process during the experiment is observed via a digital micro-observing system. It is found that the arcing process can be obviously observed under a high frequency voltage compared with that under low frequency voltage. It is also found that under different frequency voltages the electrical tree initiation shape is different. Most of the electrical trees are branch-shape tree under lower frequency voltage. When the frequency is higher than 5 kHz, trunk-shape tree and bosk-like tree appears. Once the frequency is higher than 50 kHz, breakdown tree can be found out. It is shown that the tree shape conversion is influenced by the frequency. The electrical tree usually has a simple shape and rarely changes under low frequency voltage in one hour or more. However, under a high frequency voltage, the electrical tree shape changes more frequently and has a large probability to breakdown. The influence of frequency on material polarization process, fatigue and thermo effect is considered as the main causes of the experiment results. The more serious destruction caused by high frequency electrical treeing degradation can well explain the reason of insulation premature inactivation in mid-frequency or high-frequency electrical equipment.

关键词：聚乙烯树老化电树形态转换击穿频率

来源：评论

学校读者我要写书评

暂无评论

Optimal controller Design for Non-Affine Nonlinear power systems with Static Var Compensators for Hybrid UAVs

引用

Tsinghua Science and Technology 2022年第1期27卷 196-206页

作者： Yanchu Li Qingqing Ding Shufang Li Stanimir Valtchev Beijing Key Laboratory of Network System Architecture and Convergence Beijing Laboratory of Advanced Information Networkand School of Information&Communication EngineeringBeijing University of Posts and TelecommunicationsBeijing 100876China State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua UniversityBeijing 100084China the Nova School of Science and Technology(FCT/UNL) Caparica 2829-516LisbonPortugal Technical University of Sofia(TUS) Sofia 2125Bulgaria

A generalized non-affine nonlinear power system model is presented for a single machine bus power system with a Static Var Compensator(SVC)or state Var System(SVS)for hybrid Unmanned Aerial Vehicles(UAVs).The model is constructed by differential algebraic equations on the MATLAB-Simulink platform with the programming technique of its *** the inverse system method and the Linear Quadratic Regulation(LQR),an optimized SVC controller is *** simulations under three fault conditions show that the proposed controller can effectively improve the power system transient performance.

关键词： Static Var Compensator(SVC) Unmanned Aerial Vehicles(UAV) power system non-affine nonlinear control inverse system method Linear Quadratic Regulation(LQR)

来源：评论

学校读者我要写书评

暂无评论

First stirling-type cryocooler reaching lambda point of ~4He(2.17K) and its prospect in Chinese HUBS satellite project

引用

Science Bulletin 2019年第4期64卷 219-221页

作者： Jue Wang Changzhao Pan Tong Zhang Kaiqi Luo Xiaotong Xi Xianlin Wu Jianpeng Zheng Liubiao Chen Junjie Wang Yuan Zhou Hai Jin Wei Cui University of Chinese Academy of Sciences CAS Key Laboratory of Cryogenics Technical Institute of Physics and Chemistry Chinese Academy of Sciences Laboratoire National de Métrologie Et d'essais-Conservatoire National des Arts et Métiers (LNE-Cnam) State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Department of Physics and Center for Astrophysics Tsinghua University

The issue of "missing baryons” is always an unsolved mystery in galaxy cosmology, and an important reason for the great uncertainty of the galaxies' formation and evolution. To find the "missing" baryons, extra high-resolution spectral observation and imaging of the soft X-ray band (<1 kev) is required. However, the existing observation methods cannot meet this requirement. Therefore, Tsinghua University leads and proposes the Chinese "Hot Universe Baryon Surveyor (HUBS)" satellite program.

关键词： missing baryons HUBS missing

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：