检索结果-内蒙古大学图书馆

The fault simulation experiment and feature extraction of rolling bearing based on casing measuring point

The fault simulation experiment and feature extraction of ro...

Joint Conference on Machinery Failure Prevention Technology Conference, MFPT 2016 and ISA's 62nd International Instrumentation Symposium, IIS 2016

作者： Han, Te Jiang, Dongxiang Wang, Nanfei State Key Lab. of Control and Simulation of Power System and Generation Equipments Department of Thermal Engineering Tsinghua University Beijing100084 China

In this paper, the reliability of the rolling bearing fault feature extraction based on casing vibration signals is discussed. Through the fault simulation experiment of rolling bearing, the vibration data of the outer ring fault, inner ring fault and rolling element fault, which respectively comes from bearing block measuring point and casing measuring point, is acquired. Then this paper analyzed the data from the time domain, frequency domain and amplitude domain. Analysis results show that, compared to the bearing block measuring points, due to the attenuation of the pulse signal of the fault in the transmission way and the increase of signal to noise on the casing, the fault features of casing vibration signals are significantly weakened. The envelope demodulation, FFT change on the vibration signal of casing directly cannot extract the fault characteristics. However the fault characteristic frequency can be extracted from the appropriate resonance frequency band. The results provide a reference for the fault feature extraction of rolling bearing based on the signal of casing. © 2016, Society for Machinery Failure Prevention Technology. All rights reserved.

关键词： Roller bearings

来源：评论

学校读者我要写书评

暂无评论

Blackout Risk Analysis and control of Power System Integrated with Wind Farm 28

Blackout Risk Analysis and Control of Power System Integrate...

引用

第28届中国控制与决策会议

作者： Zhong Yuxin Zhang Xuemin Mei Shengwei Xia Deming Wang Shuai Shi Rui Dept.of Electrical Engineering State Key Lab of Control and Simulation of Power Systems and Generation EquipmentsTsinghua University Northeast Branch of State Grid Corporation of China State Power Economic Research Institute

ISBN: (纸本)9781467397155

With the increase of wind power penetration,the characteristics of the wind farm have brought a significant impact on the security of power *** is urgent to study how to reduce the risk of cascading failures while improving the environmental *** this paper,a cascading failure model containing wind farm is proposed,which considers wind power characteristics,such as the structure of wind farm,the randomness of power of wind farm,the virtual inertia control of wind turbine,and the disconnection response of wind turbine after short-circuit *** order to identify the key factors of blackout,decision tree is used to analyze results generated from this blackout *** control is adopted to decrease the probability or effect of critical attributes that can be found in decision *** blackout risk of IEEE 30 test system integrated with wind farm is *** key factors,such as disconnection of wind turbines from the grid and certain transmission lines,are identified by decision ***,the effectiveness of the virtual inertial control of wind turbine,reactive power compensation and line construction is verified by simulation.

关键词： Wind Farm Disconnection of Wind Turbines Virtual Inertial control Blackout Risk Decision Tree

来源：评论

学校读者我要写书评

暂无评论

An Evolution Model with High Proportion of Renewable Energy 35

An Evolution Model with High Proportion of Renewable Energy

引用

第35届中国控制会议

作者： ZHANG Weiqi ZHANG Xinyan XIA Yukai HUANG Shaowei XIAO Jinyu LU Chang MEI Shengwei College of electrical engineering Xinjiang University State Key Lab of Control and Simulation of Power Systems and Generation Equipments (Dept.of Electrical Engineering Tsinghua University) State Power Economic Research Institute

ISBN: (纸本)9781509009107

Compared with other conventional energy sources,renewable energy,which results in less pollution and has numerous resources,is a significant factor in addressing the current issues of the serious environmental pollution and the resource ***-scale renewable energy connected to the grid could lead to a the change of the morphological structure and the operation modes of energy *** current power grid evolution models did not consider the characteristics of renewable energy in the evolution *** expansion mechanism of the future transmission network with a high proportion of renewable energy is studied in this *** operation cost including renewable energy curtailment are optimized using the production simulations,where the stochastic and intermittent of wind and solar energy are *** the dual variable information is adopted to drive the grid *** expansion strategies for power grid of Zhejiang province in China are analyzed to balance the construction cost and curtailment cost of renewable energy.

关键词： Renewable energy Network evolving model Transmission planning Production simulation

来源：评论

学校读者我要写书评

暂无评论

High impedance fault detection on distribution systems with harmonic interference in wind farms 13

High impedance fault detection on distribution systems with ...

引用

13th International Conference on Development in Power System Protection 2016, DPSP 2016

作者： Ni, Jiang Wang, Bin Dong, Xinzhou State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing100084 China

ISBN: (纸本)9781785618260

High impedance faults (HIFs) are easy to occur in collective feeders in wind farms and may cause the cascading of wind generators tripping. This kind of faults is difficult to be detected by traditional relay or fuse due to the limited fault current values and the situation is worse in wind farms. The mostly adopted HIF detection algorithms are based on the 3rd harmonic characteristic of the fault zero-sequence currents, whereas these 3rd harmonics are very easy to be polluted by wind power back-to-back converters. To solve this problem, the typical HIF arc flash based on Mayr's arc model is first built, and the typical fault waveforms of HIF in wind farm are presented. Then the characteristics of high impedance faults are analysed to distinguish the occurrence of HIF from other harmonic interference. After that, the performance of the traditional harmonic based HIF detection algorithm is discussed, and a novel detection algorithm is presented to prevent harmonic interference influence in wind farms.

关键词： Electric utilities

来源：评论

学校读者我要写书评

暂无评论

Weather type partition method considering sequential features in photovoltaic forecasting

引用

The Journal of Engineering 2017年第13期2017卷 1259-1263页

作者： Hao Li Zongxiang Lu Ying Qiao Ningbo Wang Kun Ding State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Haidian District Beijing 100084 People's Republic of China Wind Power Technology Center Gansu Electric Power Corporation Lanzhou 730050 People's Republic of China

The prediction method based on the partition of weather types has been widely used in photovoltaic prediction. Here, the temporal characteristics of PV data is studied, the physical meaning of the sequential difference sequences is analysed, and a characteristic index system including sequential characteristics index is proposed. The weather types are partitioned based on self-organising map neural network algorithm. Case study shows that the partition method is helpful to improve the discrimination of weather types and to improve prediction accuracy.

关键词： load forecasting photovoltaic power systems prediction theory self-organising feature maps power engineering computing self-organising map neural network algorithm characteristic index system sequential difference sequence analysis PV data characteristics photovoltaic prediction method photovoltaic forecasting weather type partition method

来源：评论

学校读者我要写书评

暂无评论

An Economic Evaluation of Electric Vehicle Charging Infrastructure in Public Places in China

引用

IOP Conference Series: Earth and Environmental Science 2018年第1期168卷

作者： Xueqi Huang Xiao Li Xinmei Yuan Bo He Juan Li State Key Lab. of Automotive Simulation and Control Jilin University Changchun China Department of Power Grid Development State Grid Energy Research Institute Beijing China State Grid Tianjin Electric Power Economic Technology Research Institute State Grid Tianjin Electric Power Company Tianjin China

The electric vehicle market has witnessed a big growth spurt as a result of the promotion of the transportation electrification in the global. Among electric vehicles, electric passenger cars are the most promising fleet to achieve the global climate target in the next decades, which will lead to a vast potential public charging market. Therefore, evaluating the economy of operating the charging infrastructure from the operator's perspective is especially required. The paper aims at providing an economic evaluation of charging infrastructure in public places in China. In the proposed method, the initial investment cost, the subsidy, the operating revenue and the operating cost are all modeled in detail. Using the proposed model, two scenarios representing the electric vehicle charging in the work place and in the fast charging station are assumed, and the cost and revenue of charging operators are calculated and compared. It is shown that under our assumption the payback period of the charging infrastructure in the work place is much shorter than that of fast charging station. Because the calculated payback period of fast charging station is more than ten years, current fast charging stations are unlikely to profit, and the promotion of the fast charging stations requires further policy support and smart grid technology development.

关键词：

来源：评论

学校读者我要写书评

暂无评论

凝变除湿复合烟气深度净化技术工程应用

引用

Engineering 2018年第3期 253-262页

作者：刘建民朱法华马修元 State Power Environmental Protection Research Institute State Environmental Protection Key Lab for Air Physical Simulation & Pollution Control

湿法脱硫后湿烟气排放会形成湿烟羽现象,不仅浪费水资源,产生视觉污染,同时湿烟气中的SO3、溶解在液态水中的盐、颗粒物等在大气环境中会形成二次污染。本文提出了一种凝变除湿复合烟气深度净化技术,包括凝变湿电一体化和凝变除雾一体... 详细信息

湿法脱硫后湿烟气排放会形成湿烟羽现象,不仅浪费水资源,产生视觉污染,同时湿烟气中的SO3、溶解在液态水中的盐、颗粒物等在大气环境中会形成二次污染。本文提出了一种凝变除湿复合烟气深度净化技术,包括凝变湿电一体化和凝变除雾一体化两种技术路线,分别在630 MW和1000 MW燃煤机组上进行了工程应用。结果表明,凝变除湿复合烟气深度净化技术对脱硫后饱和湿烟气的除水量大于4 g·kg-1·℃-1,在烟气温度降低1.5～5.3℃时,可回收烟气中5%～20%的水分,有效节约水资源;显著减少水汽排放,有效消除湿烟羽现象;离子浓度降低65%以上,SO3脱除率大于75%,颗粒物脱除率为92.53%。

关键词：湿烟羽凝变除湿溶解盐 SO3 颗粒物

来源：评论

学校读者我要写书评

暂无评论

Measurement techniques on transient process of lightning striking overhead transmission lines

Measurement techniques on transient process of lightning str...

引用

CIGRE Session 46

作者： Xie, S.J. Li, J.M. Zhang, Y. Zeng, R. Zhuang, C.J. Wang, H. State Grid Sichuan Electric Power Research Institute State Grid Sichuan Electric Power Company China State Key Lab. of Control and Simulation of Power Systems and Generation Equipment Tsinghua University China

Obtaining the lightning strike density along an overhead transmission line and identifying the lightning strike types are the key to evaluating the lightning protection performance and proposing reasonable protection schemes of transmission lines. In addition, the waveform characteristics of lightning invasion overvoltage are the basis to establish the standard on the insulation tests of power equipment. Measuring the transient process of lightning striking overhead transmission lines is the basis to carry out the work mentioned above. In this paper, a distributed measurement method of transient current on conductors caused by lightning strikes is proposed. The measuring units are installed on the field conductors of transmission lines every 30 km to obtain less-distorted transient current waveforms. In order to enable measuring units to work in field isolated environment, a power supply coil using Faraday electric-magnetic effect and a wireless communication module is designed and developed. By far, 4776 measuring units have been installed on 597 transmission lines of China's power grid. According to measured transient current waveforms, the lightning strike point can be located using the double-end or single-end travelling wave location method, and the lightning strike type can also be identified. Moreover, a novel measurement method of lightning transient voltage based on the integrated optical electric field sensor (IOEFS) is proposed. In this method, the transient voltage waveforms are inversed from space electric field waveforms measured by IOEFSs. A series of performance tests of IOEFS have been carried out. The test results indicate that the response speed can reach several nanoseconds, and the frequency response can cover 5Hz∼100MHz which is wide enough for the measurement of the lightning transient voltage. In order to test the field measurement effect, the measurement equipment is used to measure a transient voltage when a group of capacitor voltage trans

关键词： Frequency response

来源：评论

学校读者我要写书评

暂无评论

Voltage balance optimisation among subsystems of wind-photovoltaic-ES hybrid generating system

引用

The Journal of Engineering 2017年第13期2017卷 854-858页

作者： Han Wu Yan Li Zongxiang Lu Haiyan Tang State Key Lab of Control and Simulation of Power Systems and Generation Equipments (Dept. of Electrical Engineering Tsinghua University) Haidian District Beijing 100084 People's Republic of China North China Electric Power Research Institute Co. Ltd Beijing 100045 People's Republic of China State Key Laboratory of Operation and Control of Renewable Energy & Storage Systems (China Electric Power Research Institute) Haidian District Beijing 100192 People's Republic of China

Wind-photovoltaic-energy storage (ES) hybrid generating system has numerous reactive power sources. It is crucially important for coordinated control of these reactive power sources. According to the test results, there are unbalanced control problem in subsystem voltage of the hybrid generating system. The problem caused reactive power circulation and loop current. A subsystem voltage balance optimisation strategy is proposed to solve the problem. The case study shows the efficiency of the proposed strategies.

关键词： electric potential wind power photovoltaic power systems reactive power electric power generation reactive power sources wind-photovoltaic-ES hybrid generating system subsystems voltage balance optimisation

来源：评论

学校读者我要写书评

暂无评论

Photoreactivity of Metal-Organic Frameworks in Aqueous Solutions: Metal Dependence of Reactive Oxygen Species Production

引用

Environmental Science and Technology 2016年第7期50卷 3634-3640页

作者： Liu, Kai Gao, Yanxin Liu, Jing Wen, Yifan Zhao, Yingcan Zhang, Kunyang Yu, Gang School of Environment Beijing Key Laboratory for Emerging Organic Contaminants Control State Key Joint Laboratory of Environmental Simulation and Pollution Control Tsinghua University Beijing100084 China MOE Key Lab. of Environmental Remediation and Ecosystem Health College of Environmental and Resource Sciences Zhejiang University Hangzhou310058 China Lyles School of Civil Engineering Division of Environmental and Ecological Engineering Purdue University West LafayetteIN47907 United States

Promising applications of metal-organic frameworks (MOFs) in various fields have raised concern over their environmental fate and safety upon inevitable discharge into aqueous environments. Currently, no information regarding the transformation processes of MOFs is available. Due to the presence of repetitive π-bond structure and semiconductive property, photochemical transformations are an important fate process that affects the performance of MOFs in practical applications. In the current study, the generation of reactive oxygen species (ROS) in isoreticular MIL-53s was studied. Scavengers were employed to probe the production of 1O2, O2•-, and •OH, respectively. In general, MIL-53(Cr) and MIL-53(Fe) are dominated by type I and II photosensitization reactions, respectively, and MIL-53(Al) appears to be less photoreactive. The generation of ROS in MIL-53(Fe) may be underestimated due to dismutation. Further investigation of MIL-53(Fe) encapsulated diclofenac transformation revealed that diclofenac can be easily transformed by MIL-53(Fe) generated ROS. However, the cytotoxicity results implied that the ROS generated from MIL-53s have little effect on the viability of the human hepatocyte (HepG2) cell line. These results suggest that the photogeneration of ROS by MOFs may be metal-node dependent, and the application of MIL-53s as drug carriers needs to be carefully considered due to their high photoreactivity. (Chemical Equation Presented). © 2016 American Chemical Society.

关键词： Photoreactivity

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：