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A Multi-Objective Model with Probability Constraints of Trans-Provincial Hydropower Consumption Considering Dynamic Stability Limit

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IOP Conference Series: Materials Science and Engineering 2019年第1期692卷

作者： Ke Yang Rui Mao Xu Wen Chuncheng Gao Miao Huang Wei Yan Southwest Subsection of State Grid Chengdu China State Key Laboratory of Power Transmission Equipment & System Security and New Technology(Chongqing University) Chongqing China College of Automation Chongqing University of Posts and Telecommunications Chongqing China Beijing Ke Dong Electric Power Control System Co. Ltd.Beijing China Nari Group Corporation/State Grid Electric Power Research Institute Nanjing China

With the rapid development of clean energy and serious delay of grid construction, water abandonment is becoming more and more severe. Under this condition, this paper proposed a multi-objective model with probability constraints of trans-provincial hydropower consumption considering dynamic stability limit. Firstly, a mathematical expression about the dynamic stability limit of trans-provincial channel is constructed. Secondly, a risk assessment index of abandoned water is established on the basis of semi-absolute deviation. Then, based on the framework of stochastic programming, a multi-objective model with probability constraints is proposed for hydropower transmission in trans-provincial trade. By means of genetic algorithm with embedded Monte-Carlo simulation technology, the model can be solved efficiently. Finally, data of Tibet power grid is calculated to verify the validity and universality of the research. The results show that the established model can achieve optimal economic benefit between grid companies and generation enterprises, and also effective management of water abandonment risk.

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Maintenance Scheduling of Power Equipment Considering Opportunistic Maintenance Strategy

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IOP Conference Series: Materials Science and Engineering 2019年第1期486卷

作者： Bo Xu Yumin Zhang Kongming Sun State Grid Energy Research Institute Co. Ltd. Beijing China Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong University Jinan 250061 Shandong Province China State Grid Shandong Electric Power Research Institute Jinan 250003 Shandong Province China

This paper investigates the impact of opportunistic maintenance strategy on power equipment maintenance scheduling under economic dependence. The model focuses on power equipment with two types of failures: random failure and deterioration failure. Unlike previous research which didn't consider opportunistic maintenance between different failures modes, opportunistic maintenance strategy is proposed in this paper. In the opportunistic maintenance strategy, whenever random failure occurs, decision has to be made on whether deterioration failure is preventively maintained based on the degree of equipment deterioration and economic dependence. Firstly, Markov process is used to describe equipment state-space diagram. And then, in order to determine the optimal inspection rate, preventive maintenance threshold and opportunistic maintenance threshold of power equipment, the analytical expressions of inspection cost, maintenance cost, repair cost and outage cost are quantified. Finally, the total cost is minimized to get the optimal maintenance strategy. Case studies demonstrate the feasibility of the proposed model.

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Diagnosis method for rub-impact fault of rotating machinery based on EMD and Hilbert envelop spectrum

Diagnosis method for rub-impact fault of rotating machinery ...

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

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

Aiming at the characteristics of the casing vibration acceleration signal of rotating machinery with rubbing fault, a diagnosis method based on EMD (empirical mode decomposition) and Hilbert envelop spectrum is put forward. When the rubbing fault occurs between the rotor and the stator, the vibration acceleration signals from the casing of the rooting machinery will present amplitude-modulated feature due to the periodical rub-impact between the rotor and the stator. However, it is relatively difficult to extract the rub-impact feature since the rub-impact signal in the process of transferring to the casing is always buried in the noise and background signals. In this paper, by means of the powerful capability of EMD and Hilbert envelop spectrum in processing nonlinear signal can accurately describe nonlinear behaviours, the fault signal is adaptively decomposed by EMD to acquire intrinsic mode functions (IMF) containing obvious feature of amplitude modulation. Then some of the sensitive IMF components are transformed by FFT and their Hilbert spectrum are analysed. The analysis results from the experimental signal show that the EMD provides an effective and adaptive method to obtain 'purified' casing vibration acceleration signal, which demonstrates the transient casing vibration more precisely and vividly, decreasing misinterpretation of the machine running condition. Therefore, the EMD approach can be applied to the single-point rubbing fault diagnosis of the rotor systems efficiently. © 2016, Society for Machinery Failure Prevention Technology. All rights reserved.

关键词： Empirical mode decomposition

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Damping Analysis and Test Research of a Composite Leaf Spring in a Light Bus

Damping Analysis and Test Research of a Composite Leaf Sprin...

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2016中国汽车工程学会年会暨展览会

作者： Shi Wenku Qian Chen Song Qianqian Gao Bo Ke Jun State Key Laboratory of Automotive Simulation and Control Jilin University

ISBN: (纸本)9789811035272;9789811035265

In order to study damping characteristic and its influencing factors of E glass fiber/polyurethane composite leaf spring,we use finite element simulation *** a detailed research method of it:According to the structure semesters of the spring,building 3D models of composite laminate and spring and carrying out the grid division by the finite element software HYPERMESH and the mechanical property parameters of the material were given to the model;making tests of composite laminate and spring and convert the results into simulation semesters of the model;we make analysis by finite element software ABAQUS and compare the simulation results with the experimental results to find out that the mainly influence factors of composite leaf spring damping characteristic are laying angle and longitudinal tensile modulus of *** results show that 0 angel layer damping ratio is 0.0074 belongs to small damping *** all,our research provides theoretical basis and research methods for studying composite leaf spring damping characteristic.

关键词： bus composite leaf spring finite element analysis damping characteristic analysis

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Modelling and control of doubly fed variable-speed pumped storage units for grid power regulation

Modelling and control of doubly fed variable-speed pumped st...

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6th International Conference on Renewable Power Generation

作者： Guopeng, Zhao Qiang, Zhao Jiyun, Ren Xiaofang, Song Minxiao, Han State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing102206 China School of Electrical and Electronic Engineering North China Electric Power University Beijing102206 China State Key Laboratory of Smart Grid Protection and Control Nanjing Jiangsu Province211006 China

With the expending scale of the power grid and the substantial development of renewable energy generation system, the demand for power quality is becoming more and more significant. The doubly fed pumped storage can be an effective method to control the power of the power grid and restrain the power grid fluctuation caused by renewable energy generation. First, this study introduces the structure of doubly fed pumped storage unit, and analyses the mathematical model of reversible hydraulic pump turbine, doubly fed induction generator (DFIG) and control strategy of the converter. On the basis of the model of reversible hydraulic pump turbine and DFIG, control strategies of the dq decoupling and synchronous rotating coordinate system are studied to output the active and reactive power. Second, the models of generating mode and pumping mode for the doubly fed pumped storage unit are established. Third, for the grid power regulation, active power and speed control strategy in generating mode, pumping mode are put forward. Finally, the model of doubly fed pumped storage unit of 300 MW is established in MATLAB/Simulink. The proposed control strategy is verified by the simulation results. © 2017 Institution of Engineering and Technology. All Rights Reserved.

关键词： Renewable energy resources

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A comparative analysis of precipitation estimation methods for streamflow prediction 22

A comparative analysis of precipitation estimation methods f...

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22nd International Congress on Modelling and simulation: Managing Cumulative Risks through Model-Based Processes, MODSIM 2017 - Held jointly with the 25th National Conference of the Australian Society for Operations Research and the DST Group led Defence Operations Research Symposium, DORS 2017

作者： Guo, B. Xu, T. Zhang, J. Croke, B. Jakeman, A. Seo, L. Lei, X. Liao, W. Beijing Key Laboratory of Resource Environment and Geographic Information System Capital Normal University Beijing100048 China Centre Fenner School of Environment and Society Australian National University ACT Australia Mathematical Sciences Institute Australian National University ACT Australia China Institute of Water Resources Hydropower Research State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin Beijing100038 China

ISBN: (纸本)9780987214379

Surface hydrologic models are widely used for streamflow prediction, forecasting and for understanding hydrologic processes. They are also an important tool for contributing to the resolution of wider resource and environmental issues, providing information to support policies and decisions for water resource management. Precipitation is a key input to hydrologic models and is however also the major source of predictive uncertainty. Whilst station-based observed precipitation data can be adequate for hydrologic modelling in small catchments, they may not be sufficient for large catchments, in particular for large catchments with a mountainous terrain. Areal estimation of precipitation is a potential option to provide more precise precipitation input to models for large catchments. Conventionally, for areal precipitation estimation, station-based precipitation data are interpolated across the model domain using various methods, including Spline fitting, Inverse Distance Weighting (IDW) and the classical Thiessen Polygon, which are among the more popular and commonly used methods. Different precipitation interpolation methods will affect the spatial and temporal variability of areal precipitation inputs, resulting in different uncertainties when used to help calibrate a surface hydrologic model. This paper investigates the effect of the above three types of precipitation interpolation methods (ANUSPLIN surface, IDW surface and Thiessen polygon) on streamflow predictions. The Chaohe basin located in northern China is selected as the study area. It is an important headwater of the Miyun Reservoir which provides drinking water to Beijing and surrounding townships. Three lumped, surface hydrologic models (GR4J, IHACRES and Sacramento) are selected to study the accuracy and predictive uncertainty of these three types of precipitation interpolation on daily streamflow. The models were calibrated separately using discharge observations from three gauges in the basin. The res

关键词： Catchments

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Study on Effects of Multiple Injection at Intake Stroke on Combustion and Emissions of GDI Engine under Warm up Conditions

Study on Effects of Multiple Injection at Intake Stroke on C...

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2016中国汽车工程学会年会暨展览会

作者： Dong Wei Pu Chaojie Sun Yao Qiu Litao Ma Bin State Key Laboratory of Automotive Simulation and Control Jilin University

ISBN: (纸本)9789811035272;9789811035265

An experimental investigation of multiple injection at intake stroke under warm up conditions was performed in a GDI *** a constant excess air ratio,the effects of multiple injection strategy at intake stroke on the combustion and emissions were *** results showed that,compared to single injection,with the increase of injection times and coolant water temperature,cylinder pressure increased and its corresponding crank angle was advanced for multiple injection at intake stroke,while the peak transient heat released ratio increased,but its occurrence timing was slightly ***,THC emissions decreased obviously for multiple injection,but NOx emissions *** injection at intake stroke can reduce particle number concentration under warm up conditions,and the particle number concentration decreased with the increase of coolant ***,when at low coolant temperature,the size of particle number concentration performed as bimodal distribution of nucleation mode and accumulation *** the increase of coolant temperature,the peak size of particle number concentration behaves as a unimodal *** Comparing to the third injection timing for three different injection modes,it shows that,with the advance in injection time,the peak cylinder pressure and the maximum transient heat released rate increased,while corresponding crank angle was ***,NOx emissions increased,but THC emissions and the particle number concentration decreased.

关键词： GDI warm up multiple injection combustion emissions

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An Adaptive INS/GPS/VPS Federal Kalman Filter for UAV Based on SVM

An Adaptive INS/GPS/VPS Federal Kalman Filter for UAV Based ...

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IEEE International Conference on Automation Science and Engineering

作者： Xuan Xiao Chao Shi Yi Yang Yuan Liang Xiang Guo School of Automation and State Key Laboratory of Complex System Intelligent Control and Decision Beijing Institute of Technology Beijing China

In this paper, an adaptive modified federal Kalman filter is applied to the autonomous navigation with multi-sensors in condition that Unmanned Aerial Vehicle (UAV) is dynamically tracking Unmanned Ground Vehicle (UGV). To satisfy the autonomous navigation demands such as good accuracy, real time and high reliability for UAV, a new integrated navigation mode, in which Inertial Navigation system (INS) is aided by Global Position system (GPS)/Visual Positioning system (VPS), is proposed. Subsequently, a novel method is introduced which determined the information-sharing factors dynamically based on Singular Value Decomposition (SVD), and it not only solves the blindness of the information distribution factor of the conventional federated filter but also reduces the amount of calculation. According to the analysis of the theory about Support Vector Machine (SVM), an optimal objective kernel function is designed to select the effective source of information, thus it isolates the fault sensor. simulation results show that the proposed integrated navigation system can provide abundant navigation information with sub-level navigation accuracy and good fault-tolerant performance. UAV can obtain reliable navigation information by this modified federal Kalman filter algorithm even when GPS or VPS is continuously interrupted for a period.

关键词： UGV UAV provide abundant

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Effect of salinity on community structure and naphthalene dioxygenase gene diversity of a halophilic bacterial consortium

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Frontiers of Environmental Science & Engineering 2016年第6期10卷 41-48页

作者： Tingting Fang Ruisong Pan Jing Jiang Fen He Hui Wang State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China Development and Promotion Center of Environmental Science and Technology Changzhou 213001 China

The aim of this study is to analyze the effect of salinity on polycyclic aromatic hydrocarbons （PAHs） biodegradation, community structure and naphthalene dioxygenase gene （ndo） diversity of a halophilic bacterial consortium with the denaturing gradient gel electrophoresis （DGGE） approach. The consortium was developed from oil-contaminated saline soil after enrichment for six times, using phenanthrene as the substrate. The prominent species in the bacterial consortium at all salinities were identified as halophilic bacteria Halomonas, Alcanivorax, Marinobacter, Idiomarina, Martelella and uncultured bacteria. The predominant microbes gradually changed associating with the saline concentration fluctuations ranging from 0.1% to 25% （w/v）. Two ndo alpha subunits were dominant at salinities ranging, from 0.1% to 20%. while not been clearly detected at 25% salinity. Consistently. the biodegradation occurred at salmltles rangmg from 0.1% to 20%, while no at 25% salinity, suggesting the two ndo genes played an important role in the degradation. The phylogenetic analysis revealed that both of the two ndo alpha subunits were related to the classic nab-like gene from Pseudomonas stutzeri AN10 and Pseudomonas aeruginosa PaK1, while one with identity of about 82% and the other one with identity of 90% at amino acid sequence level. We concluded that salinity greatly affected halophilic bacterial community structure and also the functional genes which were more related to biodegradation.

关键词： Phenanthrene Halophilic bacteria Gene diversity Naphthalene dioxygenase genes

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Author Correction: Near-real-time monitoring of global CO2 emissions reveals the effects of the COVID-19 pandemic

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Nature communications 2020年第1期11卷 6292页

作者： Zhu Liu Philippe Ciais Zhu Deng Ruixue Lei Steven J Davis Sha Feng Bo Zheng Duo Cui Xinyu Dou Biqing Zhu Rui Guo Piyu Ke Taochun Sun Chenxi Lu Pan He Yuan Wang Xu Yue Yilong Wang Yadong Lei Hao Zhou Zhaonan Cai Yuhui Wu Runtao Guo Tingxuan Han Jinjun Xue Olivier Boucher Eulalie Boucher Frédéric Chevallier Katsumasa Tanaka Yiming Wei Haiwang Zhong Chongqing Kang Ning Zhang Bin Chen Fengming Xi Miaomiao Liu François-Marie Bréon Yonglong Lu Qiang Zhang Dabo Guan Peng Gong Daniel M Kammen Kebin He Hans Joachim Schellnhuber Department of Earth System Science Tsinghua University Beijing China. zhuliu@***. Laboratoire des Sciences du Climat et de l'Environnement LSCE CEA CNRS UVSQ Centre d'Etudes Orme de Merisiers Gif-sur-Yvette France. Department of Earth System Science Tsinghua University Beijing China. Department of Meteorology and Atmospheric Science The Pennsylvania State University University Park PA USA. Department of Earth System Science University of California Irvine 3232Croul Hall Irvine CA USA. Division of Geological and Planetary Sciences California Institute of Technology Pasadena CA USA. Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA. Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of Environmental Science and Engineering Nanjing University of Information Science and Technology Nanjing China. Key Laboratory of Land Surface Pattern and Simulation Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China. Climate Change Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China. Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China. School of Environment Tsinghua University Beijing China. School of Mathematical School Tsinghua University Beijing China. Department of Mathematical Sciences Tsinghua University Beijing China. Center of Hubei Cooperative Innovation for Emissions Trading System Wuhan China. Faculty of Management and Economics Kunming University of Science and Technology 13 Kunming China. Economic Research Centre of Nagoya University Furo-cho Chikusa-ku Nagoya Japan. Institut Pierre-Simon Laplace Sorbonne Université/CNRS Paris France. Université Paris Dauphine Place du Maréchal de Lattre de Tassigny 75016 Paris France.

A Correction to this paper has been published: https://***/10.1038/s41467-020-20254-5.

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