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SSRN 2023年

作者： Lyu, Liqun Ji, Zhongrui Yin, Hang Wang, Junfang Yang, Wenjuan Tan, Jianwei Hao, Lijun Wang, Xin Wang, Huaiyu Ge, Yunshan Wang, Yachao School of Mechanical Engineering Beijing Institute of Technology Beijing100081 China Emission Regulation Office Weichai Power Co. Ltd. Weifang261061 China State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation Chinese Research Academy of Environmental Sciences Beijing100012 China Shandong Shengxiang Intelligent Manufacturing Co. Ltd. Weifang262100 China

NOx emission from diesel vehicles generally deteriorates with the increased durability mileage due to the wear and deterioration of engines, after-treatment systems, etc. Three China-VI heavy-duty diesel vehicles (HDDVs) were selected for four-phase real driving emission (RDE) tests in this paper. After 200,000 km of on-road driving, long-term NOx measurement by portable emission measurement system (PEMS) reveals that the maximum NOx emission factors (387.06 mg/kWh) of test HDDVs are significantly lower than the NOx limit of 690 mg/kWh. For any driving condition, the NOx conversion efficiency of Selected Catalytic Reduction (SCR) falls off almost linearly as durability mileage rises. Importantly, a discernible temperature difference is shown in NOx conversion efficiency deterioration, with the NOx conversion efficiency deterioration rate under low-temperature interval being much higher than that under high-temperature. The NOx conversion efficiency at 200℃ drops by 16.67% ~ 19.82% with the higher durability mileage;however, the highest values at 275℃ ~ 400℃ barely decrease by 4.11%. Interestingly, the de-NOx performance of the SCR catalyst at 250°C demonstrates strong durability, with the maximum NOx conversion efficiency only declining by 2.11% due to the higher durability mileage. With the increased durability mileage, the de-NOx performance deterioration also causes a roughly linear increase in NOx specific emissions under all driving conditions. Urban driving conditions dramatically increase NOx specific emissions compared to the other two. Under urban driving conditions, the poor durability of SCR catalyst under low-temperature intervals and low NOx conversion efficiency have created significant difficulties for HDDVs’ NOx emission control and urban atmospheric protection. The moving average window (MAW)-based NOx results’ linear fitting correlation coefficient is 0.90 ~ 0.92, indicating that the results may be trusted. After 702,700 km of on-road driving, Vehi

关键词： Durability

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Research on the corrosive effect of inactive sulfur on oil-paper insulation 7

Research on the corrosive effect of inactive sulfur on oil-p...

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7th IEEE International Conference on High Voltage Engineering and Application, ICHVE 2020

作者： Gao, Sihang Li, Jiajun Ke, Tingjing Liu, Yang Ding, Dong Key Laboratory of Industrial Internet of Things and Networked Control Ministry of Education Chongqing University of Posts and Telecommunications Chongqing China State Grid Chongqing Electric Power Company Chongqing Chongqing China Baoding Electric Power Corporation Baoding China State Key Lab. of Transmission Distribution Equipment and Power System Safety and New Technology Chongqing University Chongqing China

ISBN: (纸本)9781728155111

Sulfur corrosion induced by active sulfur has been proved to significantly decrease the insulation performance of oil-immersed equipment. In order to protect the oil-paper insulation from sulfur corrosion, active sulfur is cleared in the refining process of crude oil. Some inactive sulfur with high-efficiency antioxidant is still retained in the mineral oil to improve the oxidation stability of oil, such as thiophenic compounds. However, the corrosive effect of inactive sulfur on the oil-paper insulation has not yet clear. Therefore, thiophene that is the largest content of sulfide in the insulating oil was selected as the research object, a series of accelerated thermal ageing experiments of oil-paper without and with thiophene under the different high temperature were conducted, scanning electron microscope equipped with an energy-dispersive X-ray spectrometer (SEM/EDX) and inductively coupled plasma atomic emission spectrometry (ICP-AES) were used to characterize the corrosion degree of oil-paper insulation. The results show that no corrosive deposit was observed on the surface of oilpaper insulation without thiophene even at very high temperature, while a few corrosive deposit was accumulated on the surface of oil-paper insulation with 500 mg/kg thiophene. The corrosion degree of oil-paper insulation with thiophene had an uptrend as the increase of temperature (130°C-180°C), preliminarily indicating that thiophene may be activated in the oil-paper system under the action of overheating fault of oil-immersed transformer and posed a corrosion threat to oil-paper insulation. © 2020 IEEE.

关键词： Scanning electron microscopy

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Frequency support scheme based on parametrized power curve for de-loaded wind turbine under various wind speed

arXiv

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arXiv 2021年

作者： Zhong, Cheng Lv, Yueming Li, Huayi Chen, JiKai Li, Yang Key Laboratory of Modern Power System Simulation and Control Renewable Energy Technology （Ministry of Education） Northeast Electric Power University Jilin132012 China Department of Electronic Electrical and Systems Engineering University of Birmingham BirminghamB15 2TT United Kingdom

With increased wind power penetration in modern power systems, wind plants are required to provide frequency support similar to conventional plants. However, for the existing frequency regulation scheme of wind turbines, the control gains in the auxiliary frequency controller are difficult to set because of the compromise of the frequency regulation performance and the stable operation of wind turbines, especially when the wind speed remains variable. This paper proposes a novel frequency regulation scheme (FRS) for de-loaded wind turbines. Instead of an auxiliary frequency controller, frequency support is provided by modifying the parametrized power versus rotor speed (Pw-ωr) curve, including the inertia power versus rotor speed curve and the droop power versus rotor speed curve. The advantage of the proposed scheme is that it does not contain any control gains and generally adapts to different wind speeds. Further, the proposed scheme can work for the whole section of wind speed without wind speed measurement information. The compared simulation results demonstrate the scheme improves the system frequency response while ensuring the stable operation of doubly-fed induction generators (DFIGs)-based variable-speed wind turbines (VSWTs) under various wind conditions. Furthermore, the scheme prevents rotor speed overdeceleration even when the wind speed decreases during frequency regulation control. Copyright © 2021, The Authors. All rights reserved.

关键词： Wind

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Impacts of Instantaneous Heavy Load on DC Distribution Network and Their Solution

Impacts of Instantaneous Heavy Load on DC Distribution Netwo...

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2020 IEEE/IAS Industrial and Commercial power system Asia, I and CPS Asia 2020

作者： Li, Changming Wang, Xiaohui Gong, Jinlin Ping, Chaochun Guo, Jiangyan Guo, Hong Wang, Zhidong Shandong University Key Laboratory of Power System Intelligent Dispatch and Control Jinan China Cnooc Research Institute Co. Ltd Beijing China State Grid Economic and Technological Beijing China

ISBN: (数字)9781728143033

ISBN: (纸本)9781728143033

With the gradual maturity of power electronics technology, DC distribution network has attracted wide attention. Instantaneous heavy load has an adverse effect on system performance. It will cause fluctuation of the system, resulting in poor power quality and system instability. Therefore, this paper is focused on the impacts of instantaneous heavy load on DC distribution network and their solution. Firstly, the impacts are analyzed theoretically. Then, the simulation is carried out and it confirms the analysis. Finally, the method of using energy storage devices and capacitors at photovoltaic is proposed. The method can provide energy for the system to support instantaneous heavy load, so it can improve the performance of DC distribution network during instantaneous heavy load, and meanwhile it is validated by PSCAD/EMTDC model simulation. © 2020 IEEE.

关键词： power quality

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GCN-Based Multiview User Representation Learning for Recommendation

GCN-Based Multiview User Representation Learning for Recomme...

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第32届中国过程控制会议(CPCC2021)

作者： Mingjie Cheng Jing Wu Shaoyuan Li Dan Huang Wenda Lu Lanxin Qiu Department of Automation and Key Laboratory of System Control and Information Processing Shanghai Jiao Tong University the Communication Division of State Grid Zhejiang Electric Power Co. Ltd

To alleviate the problems of sparsity and cold start,knowledge graph is introduced as auxiliary information to the recommendation ***,the existing methods based on graph convolutional network do not sufficiently mine the information in the knowledge graph,ignoring the relationship between users and the attributes of the items in knowledge *** this paper,we propose a MultiView User Representation learning(MVUR) method and a GCNbased recommendation model to directly mine the relationship between users and ***,we construct multiple user-attribute views to explore the user's preference for different attributes,thereby obtaining high-quality user representation and improving the recommendation *** evaluate our MVUR model on three real-world datasets and have better performance in Recall and NDCG indices,which prove that our MVUR model have a better effectiveness.

关键词： Recommendation Graph Convolutional Network Knowledge Graph Multiview

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Data-Driven Wind Turbine Wake Decomposition and Evolution Analysis: A Frequency Characteristics-based Clustering Procedure

Data-Driven Wind Turbine Wake Decomposition and Evolution An...

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第40届中国控制会议

作者： Zhenyu Chen Zhongwei Lin Jizhen Liu Gengda Li Feng Hu State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources School of Control and Computer Engineering North China Electric Power University Guodian New Energy Technology Research Institute Co. Ltd.

With the research in wind turbine wake deepening, frequency characteristics are gaining more attention. Data-driven methods are usually adopted to analyze the wake performance. In this paper, a frequency characteristics-based clustering procedure is proposed to decompose the wind turbine wake into clusters, of which the wake frequency-domain performance and dynamic wake evolution process can be analyzed. The proposed procedure first calculates the frequency amplitudes of the measured velocity time-series on every measurement point in space, then decomposes the wake according to the amplitudes using a clustering algorithm. Take the centroid in each cluster as an example, dominant frequency characteristics are analyzed, which show the wake meandering frequency while help the understanding of the dynamic wake evolution.

关键词： Data-Driven Frequency Characteristic Clustering Decomposition Dynamic Wake

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Research on Real-time simulation of Wide Area Out-of-step system in CSG

Research on Real-time Simulation of Wide Area Out-of-step Sy...

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IEEE Conference on Energy Internet and Energy system Integration (EI2)

作者： Lifan Mao Dongxu Chang Ruicai Liu Yihua Zhu Hengdao Guo MingKang Wu Power Dispatching and Control Center Hainan Power Grid Co.Ltd Haikou China State Key Laboratory of HVDC Electric Power Research Institute China Southern Power Grid Guangzhou China Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System Guangzhou China CSG Key Laboratory for Power System Simulation Electric Power Research Institute China Southern Power Grid Guangzhou China

ISBN: (数字)9781728196060

ISBN: (纸本)9781728196077

In order to study the action characteristics of wide area out-of-step system in CSG, the real-time simulation study based on RTDS is carried out. In this paper, a test system based on the actual devices and the settings are constructed, and the modeling methods of the important measurement such as the power angle of tie line, Ucos φ oscillation curve and the voltage at the installation point of device are studied. The operation characteristics of wide area out-of-step system are fully verified by several serious single or multiple fault cases. The analysis of the simulation results shows that the wide area out-of-step system can meet the design requirements of splitting speediness, simultaneity and selectivity, and can solve the problems of late splitting in the south channel of Guangdong and Guangxi section, as well as the problem that the system cannot recover stability after splitting Guangdong and Guangxi, Guizhou and Guangxi section simultaneously.

关键词： Voltage measurement Stability criteria power system stability Real-time systems Data models Transient analysis Oscillators

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Prediction model of multi-step attack 7

Prediction model of multi-step attack

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7th International Conference on Information Science and control Engineering, ICISCE 2020

作者： Li, Zeke Duo, Zhilin Chen, Zewen Zhao, Zilun Liang, Ye FUJIAN Electric Power Corporation BeiJing China Beijing Kedong Electric Power Control System Co. Ltd. Nari Group Corporation BeiJing China Beijing University of Posts and Telecommunications State Key Laboratory of Networking and Switching Technology Beijing China

ISBN: (纸本)9781728164069

There are many security monitoring devices running in the state gird. The security monitoring devices can detect the alerts. Correlations between these alerts are existed. A complete multi-step attack event can be divided into many stages, the serious attack events always occurs in the later stage in a complete attack. We can make better defense when facing attack if we predict the next possible attack event. This paper proposed a multi-step attack prediction model. The attack events in state gird are transformed into the original dataset, which can be considered as the input of prediction model. By using this model, state gird security personnel can use prediction model to take preventive measures from being attacked. Experiments show that the recall rate and accuracy rate of this prediction model have reached 84. 90% and 84. 91% © 2020 IEEE.

关键词： Machine learning

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Filter-Based Fault Diagnosis of Heat Exchangers 6th

Filter-Based Fault Diagnosis of Heat Exchangers

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6th International Conference on Life system Modeling and simulation, LSMS 2020, and 6th International Conference on Intelligent Computing for Sustainable Energy and Environment, ICSEE 2020

作者： Zhang, Jianhua Li, Hongrui Fan, Penghao Hou, Guolian Ren, Mifeng State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing102206 China School of Control and Computer Engineering North China Electric Power University Beijing102206 China College of Information Engineering Taiyuan University of Technology Taiyuan030024 China

ISBN: (纸本)9789813363779

In this paper, a filter is proposed to diagnose fouling and sensor faults of heat exchangers. First, a typical heat exchanger system model is established, a filter based on the survival information potential is then designed for non-Gaussian stochastic systems. Consequently, the state estimation generated by the filter is used for fault detection, and the support vector machine is then employed to identify fouling and fault location of heat exchangers. The simulation results show that the fault diagnosis of heat exchangers can be effectively. © 2020, Springer Nature Singapore Pte Ltd.

关键词： Support vector machines

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Data-Driven Modeling and Analysis of Dynamic Wake for Wind Farm control: A Comparison Study

Data-Driven Modeling and Analysis of Dynamic Wake for Wind F...

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2020 Chinese Automation Congress, CAC 2020

作者： Chen, Zhenyu Doekemeijer, Bart M Lin, Zhongwei Xie, Zhen Si, Zongming Liu, Jizhen Wingerden, Jan-Willem Van State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources School of Control Computer and Engineering North China Electric Power University Beijing China Delft University of Technology Netherlands New Energy Co. Ltd Jinan250099 China

ISBN: (纸本)9781728176871

For the study of wind farm and wake effect, the steady-state wake models like FLORIS were proposed and used during wind farm operations to achieve higher wind power utilization and conversion. However, the dynamic performance of the wake should also be involved in favor of better optimizations. In this paper, a data-driven analysis and modeling method, dynamic mode decomposition (DMD), is used to construct dynamic flow model with high-fidelity flow data. Two DMD-derived models are constructed based on flow data in three-dimensional and two-dimensional spaces, respectively. The obtained models and respective flows are compared in the time and frequency domain. Results show that both models have apparent differences in the frequency domain, but the dominant wake characteristics' consistency is maintained. © 2020 IEEE.

关键词： Dynamic mode decomposition

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