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2019 Tsinghua International Doctoral Forum

作者： Zhiao Li Laijun Chen Dangwu Liu Tianwen Zheng Bo Gao Shengwei Mei State Key Lab of Control and Simulation of Power Systems and Generation Equipments (Dept. of Electrical Engineering Tsinghua University) Haidian District Beijing 100084 China State Grid Anhui Electric Power CO. LTD. Hefei 230022 China Sichuan Energy Internet Research Institute Tsinghua University Chengdu 610213 China State Grid Anhui Electric Power Research Institute Hefei 230601 China

ISBN: (纸本)9781839533907

As the energy scarcity and environment problems become more and more severe, promoting renewable energy has become an important task and thus energy storage draws increasing attention for integrating renewable energy. Among many available options, advanced adiabatic compressed air energy storage (AA-CAES) are considered mature and affordable options for gridscale applications. However, the relatively high capital cost hinders the development of AA-CAES system. As a result, the cost-benefit analysis of AA-CAES application is studied in this paper. The thermodynamic characteristics of AA-CAES system are carefully studied and modeled. An optimal configuration method of AA-CAES capacity considering energy arbitrage is proposed and the optimal capacity of each component of AA-CAES is demonstrated. simulation results indicate that the application of AA-CAES in arbitrage market is profitable but the payback period is long. The profit estimations are more realistic compare to conventional battery model. Profitable cost range of AA-CAES is found through sensibility analysis. Augmenting electricity price to improve economic of AA-CAES is discussed at the end.

关键词： Compressed energy storage capacity allocation energy market energy market compressed air energy storage Adiabatic Renewable energy

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Degradation state assessment of rolling bearing based on variational mode decomposition and energy distribution 16th

Degradation state assessment of rolling bearing based on var...

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16th International Conference on Fracture and Damage Mechanics, 2017

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

ISBN: (纸本)9783035711684

Degradation state assessment of bearing is an important part of prognostic and health management (PHM) in rotating machinery. Generally, the energy distribution of frequency band is sensitive to degradation state for rolling bearing. Hence, a novel assessment method based on variational mode decomposition (VMD) and energy distribution is proposed in this work. Firstly, the VMD is used to decompose raw vibration signal into several components with different scales and frequency bands. These components is capable of reflecting the local characteristic of vibration signal. Then, the energy distribution of these components is utilized as feature vector. Finally, the different bearing states can be classified by the scatter plots of the first several principal components after principal component analysis (PCA). The analysis of an experimental dataset demonstrates the effectiveness of this methods. The comparative analysis shows the VMD is superior to traditional empirical mode decomposition (EMD) methods. © 2017 Trans Tech Publications, Switzerland.

关键词： Variational mode decomposition

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Rolling bearing fault feature extraction of casing vibration signal

Rolling bearing fault feature extraction of casing vibration...

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Society for Machinery Failure Prevention Technology Annual Conference 2017: 50 Years of Failure Prevention Technology Innovation, MFPT 2017

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

The health of rolling bearing plays an important part in the operation of rotating machinery like gas turbine engine. Health monitoring and fault diagnosis of rolling bearings based on vibration signals have been through great development these years. But when sensors are set on the casing instead of the bearing pedestal, and the surrounding structure is very complex, the diagnosis problem becomes much more complicated, which brings more challenges to the signal processing. In this paper, a set of signal processing methods are used to enhance and extract the impact features from casing vibration signals, and to realize the detection of rolling bearing faults. Aself-adaptive decomposition method called intrinsic time-scale decomposition (ITD) is applied to decompose the vibration signal into a series of proper rotation components and a monotonic trend, helping to extract dynamic features of the signal. Teager-Kaiser energy operator is a simple algorithm calculating the energy of a signal and is very sensitive to transient impact faults. As the fault feature transmitted to the casing is relatively week, autoregressive model (AR) and minimum entropy deconvolution (MED) are to enhance the non-stationary impact components. Experiments are taken on the rotor-bearing-casing test rig with minor defects in themain shaft bearing. Testing on the casing vibration signal, this fault feature enhancing and extracting method shows its remarkable ability in rolling bearing fault diagnosis.

关键词： Feature extraction

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Energy Internet: Concept and practice exploration

Energy Internet: Concept and practice exploration

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2017 IEEE Conference on Energy Internet and Energy System Integration, EI2 2017

作者： Cheng, Lin Qi, Ning Zhang, Fang Kong, Huichao Huang, Xuejin State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China Dongguan Power Supply Guangdong Power Grid Co. Ltd Dongguan China

ISBN: (纸本)9781538614273

Under the situations of energy crisis around the world, Energy Internet has become the focus of international academic and industrial areas. In this paper, comprehensive reviews and prospects were made based on the background and current research status of Energy Internet. Moreover, the core concept, basic structure, and operation mode of Energy Internet were introduced and discussed. Finally, constructive solutions to the current problems were proposed with the demonstration project of Energy Internet that is the Beijing New Aerotropolis, which draws the future of the Energy Internet. © 2017 IEEE.

关键词： Internet of Energy

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Preventive control for combined heat and power system: A day-ahead security constrained economic dispatch model 11

Preventive control for combined heat and power system: A day...

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11th IET International Conference on Advances in power System control, Operation and Management, APSCOM 2018

作者： Lin, Qunli Shen, Xinwei Xu, Yinliang Sun, Yong Li, Zhenyuan Guo, Qinglai Sun, Hongbin Shenzhen Environmental Science and New Energy Technology Engineering Laboratory Tsinghua-Berkeley Shenzhen Institute Tsinghua University Shenzhen China Jilin Power Grid Company State Grid Corp. of China Jilin China State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781839530043

Integrated Energy System (IES), which plays a vital role in the development of Energy Internet (EI), can improve the efficiency of energy utilization and integration of renewable energy. However, the coupling between multiple energy systems will bring new challenges to the security control of the IES, such as combined heat and power (CHP) system. For IES, the preventive control is the first line of defense to ensure that the system can keep stable operation when contingencies such as the transmission outage or generator outage happen. This paper proposes a preventive control approach for CHP system, in which a day-ahead security constrained economic dispatch (SCED) model of CHP system considering the coupling of heat and electric is formulated. The model aims to minimize the cost of the whole system, while the preventive control of the system can be achieved with the constraints considering the normal states and contingencies states. Case studies based on the IEEE 9-bus system with CHPs are presented to illustrate the approach. The case result shows that the combined electric and heat optimal dispatch is more economical than when two systems are independently optimized and operated. And the proposed preventive control approach of the CHP system can satisfy both the electric and heat demand, and system security is ensured when the N-1 contingencies happened. © 2018 Institution of Engineering and Technology. All rights reserved.

关键词： Internet of Energy

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Misalignment fault detection in dual-rotor system based on time frequency techniques

Misalignment fault detection in dual-rotor system based on t...

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Society for Machinery Failure Prevention Technology Annual Conference 2017: 50 Years of Failure Prevention Technology Innovation, MFPT 2017

作者： Wang, Nan-Fei Jiang, Dong-Xiang Han, Te State Key Laboratory of Control Simulation of Power System and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing100084 China

In order to improve the energy efficiency and compact structure, the dual-rotor structure including lowpressure rotor and high-pressure rotor has been widely used in aero-engine. Misalignment is one of the most common faults in dual-rotor system, which will causes malfunctions. It is a significant task for rotor dynamics personnel to monitor and defect faults in dual-rotor system. In the paper, the dual-rotor vibration signals are applied to solve the fault identification problem by utilizing time frequency techniques. Numerical simulations are carried out through finite element analysis of dual-rotor system with misalignment fault. Two signal processing tools namely Short Time Fourier Transform (STFT) and Continuous Wavelet Transform are used to detect the misalignment fault and compared to evaluate their diagnosis performance. The effect of addition of Signal to Noise (SNR) on three frequency techniques is presented. Experiments are carried out to obtain the vibration data of dual-rotor test rig and the results from the work show that the technique can be used for the monitoring of misalignment, which will have applications in the condition monitoring and maintenance of various types of rotating machinery.

关键词： Condition monitoring

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Non-communication Protection for Single-Phase-to-Ground Fault Feeder in Neutral Non-Effectively Grounded Distribution System

Non-communication Protection for Single-Phase-to-Ground Faul...

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IEEE General Meeting power& Energy Society

作者： Qi Jia Xinzhou Dong Shenxing Shi Xin He State Key Lab. of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China Power Dispatching Control Center Guizhou Power Grid Co. Ltd Guiyang China

ISBN: (纸本)9781538677049

The traditional non-communication protection for distribution system is only applicable to fault feeders in neutral effectively grounded distribution system or the phase-to-phase fault feeders in neutral non-effectively grounded distribution system. For single-phase-to-ground fault feeders in the latter system, the protection will fail to operate because the magnitude of the current flow in the fault-to-ground connection is too small. To solve this problem, this paper presents a new non-communication protection compatible with the fault detection principle based on comparing the polarities of the initial voltage and current traveling waves. In this technique, when a single-phase-to-ground fault occurs, the relays which detect the fault is in the forward direction will operate based on the conventional time grading coordination at first, after one relay makes tripping decision which has the fastest time setting, the relay on the opposite side will detect the sound phase current changes in a time window to accelerate the operation. Extensive Electromagnetic Transients Program (EMTP) simulation studies with respect to a typical double end feeder system whose neutral is non-effectively grounded show that the proposed technique is able to fast and accurately remove a single-phase-to-ground fault line section from both ends.

关键词： Circuit faults Relays Acceleration Circuit breakers Wavelet transforms EMTP

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Effect of UV Radiation Aging on Creepage Discharge Characteristics of High Temperature Vulcanized Silicon Rubber at High Altitude

Effect of UV Radiation Aging on Creepage Discharge Character...

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中国物理学会第二十二届全国静电学术年会

作者： JIN Fu-bao LIANG Bin ZHOU Yuang-xiang ZHONG Liu ZHANG Ling School Of Water Resources and Electric Power Qinghai University Xining80016China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Ele

Aiming at the special working environment of composite insulators at high altitude area,we investigate the creepage discharge characteristics of aged HTV(High Temperature Vulcanized,HTV)silicone rubber materials by UV(ultraviolet radiation,UV)aging method in this *** results show that the creepage discharge flashover voltage first increased,then decreased as aging time increasing,whereas the creepage discharge initial voltage was not significantly affected by aging *** aging time has little effect on creepage discharge *** aging time contributed to shorter endurance time and higher creepage discharge development *** magnitude of discharges increase rapidly in a short time after *** partial discharge detection system was used to detect the whole creepage discharge development *** to the partial discharge characteristics parameters of creepage discharge,we divided the development process of creepage discharge into initial stage,developmental stage,accelerating stage,and critical breakdown *** with characteristic parameters of unaged HTV silicone rubber,the characteristic parameters for the aged HTV silicone rubber exhibited less fluctuation and clear *** aging not only has an effect on the physicochemical and hydrophobic properties of the materials,but also accelerates the development process of creepage discharge under AC *** should be given enough attention in engineering practice,especially at high altitude area.

关键词： High temperature vulcanized silicone rubber creepage discharge UV aging creepage discharge inception voltage creepage discharge flashover voltage high altitude characteristic parameters

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Effects of Temperature on Creepage Discharge Characteristics in Oil-Impregnated Pressboard Insulation under Combined AC-DC Voltage

Effects of Temperature on Creepage Discharge Characteristics...

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中国物理学会第二十二届全国静电学术年会

The characteristics of oil-impregnated pressboard(OIP)insulation in converter transformer are different with that in traditional AC transformers due to the complication of voltage applied on valve side windings of converter *** is a serious lack of empirical research on effect of temperature on creepage discharge characteristics in OIP under combined AC-DC ***,this study investigates the characteristics spectrum of creepage discharge in OIP under combined AC-DC voltage,and explores the effect of temperature on creepage discharge characteristics under different temperature from 70 to 110℃.The experimental results show that the partial discharge inception voltage and flashover voltage decrease as temperature *** times of low amplitude discharge(LAD)decrease and amplitude of LAD *** temperature had an accelerating effect on the development of creepage discharge in the OIP under combined AC-DC voltage Meanwhile,the times of high amplitude discharge(HAD)gradually increase at each stage of creepage discharge with higher *** analysis indicates that the charge carriers easily accumulate and quickly migrate directional movement along the electric field ahead of *** residual charge carriers are more easily dissipated after ***'hump'region of LAD moves to the direction of higher discharge *** interval time between two consecutive discharges drastically *** HAD intensively appear,result in accelerating the development of creepage discharge in OIP insulation.

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

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Deep transfer network with joint distribution adaptation: A new intelligent fault diagnosis framework for industry application

arXiv

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arXiv 2018年

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

In recent years, an increasing popularity of deep learning model for intelligent condition monitoring and diagnosis as well as prognostics used for mechanical systems and structures has been observed. In the previous studies, however, a major assumption accepted by default, is that the training and testing data are taking from same feature distribution. Unfortunately, this assumption is mostly invalid in real application, resulting in a certain lack of applicability for the traditional diagnosis approaches. Inspired by the idea of transfer learning that leverages the knowledge learnt from rich labeled data in source domain to facilitate diagnosing a new but similar target task, a new intelligent fault diagnosis framework, i.e., deep transfer network (DTN), which generalizes deep learning model to domain adaptation scenario, is proposed in this paper. By extending the marginal distribution adaptation (MDA) to joint distribution adaptation (JDA), the proposed framework can exploit the discrimination structures associated with the labeled data in source domain to adapt the conditional distribution of unlabeled target data, and thus guarantee a more accurate distribution matching. Extensive empirical evaluations on three fault datasets validate the applicability and practicability of DTN, while achieving many state-of-the-art transfer results in terms of diverse operating conditions, fault severities and fault types. Copyright © 2018, The Authors. All rights reserved.

关键词： Fault detection

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