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91st IEEE Vehicular Technology Conference, VTC Spring 2020

作者： Liao, Haijun Zhou, Zhenyu Ai, Bo Guizani, Mohsen North China Electric Power University State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources School of Electric and Electronic Engineering Beijing China Beijing Jiaotong University State Key Laboratory of Rail Traffic Control and Safety Beijing China University of Idaho Electrical and Computer Engineering Department Moscow United States

ISBN: (数字)9781728152073

ISBN: (纸本)9781728152073

In this paper, we study the channel selection problem in edge computing-empowered cognitive machine-to-machine (CM2M) communications, where a massive number of machine type devices (MTDs) offload their computational tasks to a nearby edge server by opportunistically using the spectra that are temporarily unoccupied by primary users (PUs). We formulate the channel selection problem as an adversarial multi-armed bandit (MAB) problem, and combine the exponential-weight algorithm for exploration and exploitation (EXP3) and Lyapunov optimization to develop a learning-based energy-efficient solution named SEB-EXP3. It can find the long-term optimal channel selection strategy with guaranteed performance based on local information, while simultaneously achieving service reliability awareness, energy awareness, and data backlog awareness. Four heuristic algorithms are compared with SEB-EXP3 to demonstrate its effectiveness and reliability under various simulation settings. © 2020 IEEE.

关键词： Edge computing

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Analysis and suppression of subsynchronous oscillation of Rudong wind power through MMC-HVDC system

Analysis and suppression of subsynchronous oscillation of Ru...

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2021 Annual Meeting of CSEE Study Committee of HVDC and power Electronics (HVDC 2021)

作者： J. Li X. Xie J. Yang H. Li Z. Shi K. Wang C. Fu W. Yang Key Laboratory of Far-shore Wind Power Technology of Zhejiang Province Huadong Engineering Corporation Limited Power China Hangzhou Zhejiang Province 310014 China State Key lab of Control and Simulation of Power Systems and Generation Equipment (Dept. of Electrical Engineering Tsinghua University) Haidian District Beijing 100084 China

There may be complex interaction between the converter control systems of wind power and MMC-HVDC, which will lead to sub-/super-synchronous oscillation and threaten the safe and stable operation of the system. The relevant events have been reported in Guangdong Nan'ao, Shanghai Nanhui and Zhangbei projects. Rudong offshore wind power project is the first offshore wind power transmission system in China, and it is still under construction. Therefore, it is of great significance to carry out the research on the risk analysis and suppression measures of sub-synchronous oscillation in Rudong wind power MMC-HVDC system. First, the time-domain simulation model of Rudong wind power MMC-HVDC system is built in the PSCAD/EMTDC simulation model. Then, the effects of the number of wind turbine generators, wind power output and the parameters of MMC-HVDC controller on the sub-/super-synchronous oscillation characteristics of the system are further analyzed. Finally, the suppression measures based on supplementary frequency dependent gain control are proposed, the application position of the controller is discussed, and the parameter optimization method of the controller is given. The research content provides a certain guiding significance for the operation and control of Rudong wind power MMC-HVDC.

关键词： turbogenerators HVDC power transmission wind turbines power transmission control risk analysis time-domain analysis offshore installations HVDC power convertors wind power plants wind power

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Field Measurement and Analysis on The Characteristics of Transient Enclosure Voltage and Transient Ground Potential Rise in UHV GIS Substation

Field Measurement and Analysis on The Characteristics of Tra...

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International Conference on High Voltage Engineering and Application, ICHVE

作者： Shen Wei Wang Sen Wu Tao Yang Fan Gao Bing Liu Zhuoran Electric Power Research Institute State Grid Shaanxi Electric Power Company Xi'an China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing China

ISBN: (数字)9781728155111

ISBN: (纸本)9781728155128

During the switching operation of GIS Substation, the Transient Enclosure Voltage (TEV)and the Transient Ground Potential Rise (TGPR) will occur, which will have a negative impact on the safety of substation. In this paper, TEV and TGPR are measured and analyzed in a 750kV substation at different locations of GIS, under three types of operation of disconnect switch and circuit breaker, include: single closing of disconnect switch, single closing of circuit breaker, three times opening and closing of circuit breaker. From the results, the maximum value of TEV and TGPR is 22.8 kV and 19.6kV, respectively, and the TGPR is higher than the TEV at many measuring points; Compared with the circuit breaker closing operation, the disconnect switch closing operation produces less electromagnetic oscillation energy, but it have longer macro-pulse duration and more breakdown times, which explained that the failure of secondary system caused by the operation of disconnect switch is more than caused by the operation of circuit breaker; Three times opening and closing operation of the circuit breaker produces stronger electromagnetic energy and more breakdown than single closing operation of the circuit breaker.

关键词： Circuit breakers Transient analysis Substations Gas insulation Switching circuits Switches Insulators

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Capacity Optimization of Hydrogen Buffer Tanks in Renewable power to Ammonia (P2A) system

Capacity Optimization of Hydrogen Buffer Tanks in Renewable ...

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IEEE General Meeting power& Energy Society

作者： Jiarong Li Jin Lin Yonghua Song State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University University of Macau Beijing China

ISBN: (数字)9781728155081

ISBN: (纸本)9781728155098

power to hydrogen is a promising method to consume surplus renewable energy existing in the world. However, due to bottlenecks in hydrogen storage and transportation, converting hydrogen into ammonia which is a kind of hydrogen carrier with satisfied quality in storage and transportation is considered. Industrial ammonia synthesis reactors always work in constant conditions with constant flow rate of the feed gas, while hydrogen output of electrolyzers may vary sharply across renewable energy, thus hydrogen buffer tanks are required between electrolyzers and reactors to eliminate the fluctuation to some extent. The capacity of the buffer needs to be optimized due to relatively expensive cost of tanks, and the optimal capacity of the buffer actually depends on the operation flexibility of the reactor which is rarely discussed in existing literatures. This paper studies operation flexibility of the reactor first and establishes operation model of ammonia synthesis system under variable working conditions, on this basis the capacity optimization model is proposed and verified by a P2A system. At last the operation performance and the economy of P2A system are discussed, and case studies show that about 24% of total investment cost can be reduced with the consideration of operation flexibility of the reactor.

关键词： Ammonia Renewable energy sources Hydrogen Transportation Inductors Optimization Investment

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Single-stage Grid-connected Photovoltaic Generation Takes Part in Grid Frequency Regulation for Electromechanical Transient Analysis

Single-stage Grid-connected Photovoltaic Generation Takes Pa...

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2019 IEEE PES Innovative Smart Grid Technologies Asia, ISGT 2019

作者： Yan, Gangui Hu, Wenbo Jia, Qi Zhang, Shanfeng Key Laboratory of Modern Power System Simulation and Control Renewable Energy Technology Ministry of Education Northeast Electric Power University Jilin China

ISBN: (纸本)9781728135205

In order to solve the problem of insufficient frequency regulation capacity caused by the large-scale grid-connected photovoltaic (PV) generation, the active power-frequency droop control strategy and virtual inertia control strategy are proposed for single-stage grid-connected PV generation for electromechanical transient analysis. By modifying the control structure of the inverter, PV generation actively got involved in frequency regulation. The simulation results indicate that: the inverter can control the PV array to increase or decrease the active power generated according to the set droop control and virtual inertia control, so as to suppress the drop or rise of the grid frequency;in the dynamic process of frequency, the incremental power of PV generation induced by the dynamic action of the voltage vector of grid connection point is dependent on its virtual inertia control. © 2019 IEEE.

关键词： Transient analysis

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Nox Emission Durability of Modern Heavy-Duty Diesel Vehicles Based on Long-Term Real Driving Measurement

SSRN

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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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Measurement of He2* density with an auxiliary measuring electrode in atmospheric pressure plasma jet

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Plasma Science and Technology 2019年第8期21卷 51-56页

作者： Bing QI Chunxu QIN Haikun SHANG Li XIONG Key Laboratory of Modern Power System Simulation and Control&Renewable Energy Technology Ministry of EducationNortheast Electric Power UniversityJilin132012People’s Republic of China College of Biomedical Engineering Jilin Medical UniversityJilin132013People’s Republic of China

In this study, the density of metastable He2* in an atmospheric-pressure plasma jet operating in helium with 0.001% nitrogen has been measured using an auxiliary measuring electrode *** the glow discharge mode, waveforms from two grounding electrodes, including one main discharge electrode and one auxiliary electrode, are *** isolated current peak formed by Penning ionization in waveforms from the auxiliary measuring electrode is identified to calculate the density of metastable He2*.In our discharge environment, the helium metastable densities along the jet axis direction are between 2.26×1013 and 1.74×1013 cm-3,which is in good agreement with the results measured by other *** measurement technique can be conveniently applied to the diagnosis of metastable He2* in an atmospheric-pressure plasma jet array.

关键词： atmospheric plasma jet dielectric barrier discharge density of metastable helium

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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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