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Large-disturbance Stability Analysis of Power Systems with Synchronous Generator and Converter-interfaced Generation

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 997-1002页

作者： lei chen Yong Min Liangshuai hao Guangzheng Xing Yalou Li Shiyun Xu Department of Electrical Engineering Tsinghua UniversityBeijing 100084China China Electric Power Research Institute Beijing 100192China

This letter studies large-disturbance stability of the power system with a synchronous generator(SG)and a converter-interfaced generation(CIG)connected to infinite *** power system is multi-timescale and first *** is shown that the boundary of region of attraction(ROA)of the simplified model is composed of stable manifolds of unstable equilibrium point(UEP)or semi-singular point(SSP),named anchor points,and singular surface *** type of anchor point determines the dominant instability pattern of the power *** the anchor point is UEP or SSP,the dominant instability pattern is the instability of rotor angle of SG or the instability of phase-locked loop and outer control loop(OCL)of CIG,*** of dominant instability pattern can be analyzed with the relative position relationship between UEP and *** effect of OCL is *** the OCL is activated,the ROA becomes smaller and the system is more prone to instability of *** is necessary to consider the OCL when studying the large-disturbance stability of the power system.

关键词： Converter-interfaced generation large-disturbance stability outer control loop phase-locked loop synchronous generator voltage source converter

Cobalt-nitrogen co-doped porous carbon sphere as highly efficient catalyst for liquid-phase cyclohexane oxidation with molecular oxygen and the active sites investigation

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Frontiers of Chemical Science and Engineering 2024年第3期18卷 101-112页

作者： lei chen Yuan Sun Jinshan Chi Wei Xiong Pingle Liu Fang hao College of Chemical Engineering National&Local United Engineering Research Centre for Chemical Process Simulation and IntensificationXiangtan UniversityXiangtan411105China

The selective oxidation of cyclohexane to cyclohexanone and cyclohexanol(KA oil)is a challenging issue in the chemical *** present the industrial conversion of cyclohexane to cyclohexanone and cyclohexanol is normally controlled at less than 5%***,the development of highly active and stable catalysts for the aerobic oxidation of cyclohexane is necessary to overcome this low-efficiency ***,we have developed a cobalt-nitrogen co-doped porous sphere catalyst,Co-NC-x(x is the Zn/Co molar ratio,where x=0,0.5,1,2,and 4)by pyrolyzing resorcinol-formaldehyde resin *** achieved 88.28%cyclohexanone and cyclohexanol selectivity and a cyclohexane conversion of 8.88%under *** results showed that the introduction of zinc effectively alleviated the aggregation of Co nanoparticles and optimized the structural properties of the *** addition,Co0 and pyridinic-N are proposed to be the possible active species,and their proportion efficiently increased in the presence of Zn^(2+)*** this study,we developed a novel strategy to design highly active catalysts for cyclohexane oxidation.

关键词： KA oil production cyclohexane selective oxidation cobalt-nitrogen co-doped porous carbon spheres metal-organic framework

Data-driven real-time prediction for attitude and position of super-large diameter shield using a hybrid deep learning approach

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Underground Space 2024年第2期15卷 275-297页

作者： Yanbin Fu lei chen hao Xiong Xiangsheng chen Andian Lu Yi Zeng Beiling Wang Key Laboratory of Coastal Urban Resilient Infrastructures(MOE) Shenzhen UniversityShenzhen 518060GuangdongChina College of Civil and Transportation Engineering Shenzhen UniversityShenzhen 518060GuangdongChina Shenzhen Key Laboratory of Green Efficient and Intelligent Construction of Underground Metro StationShenzhen UniversityShenzhen 518060GuangdongChina Guangdong Yuehai Pearl River Delta Water Supply Limited Company Guangzhou 511458China Shanghai Tunnel Engineering and Rail Transit Design and Research Institute Shanghai 200235China

The presented research introduces a novel hybrid deep learning approach for the dynamic prediction of the attitude and position of super-large diameter shields-a critical consideration for construction safety and tunnel lining *** study proposes a hybrid deep learning approach for predicting dynamic attitude and position prediction of super-large diameter *** approach consists of principal component analysis(PCA)and temporal convolutional network(TCN).The former is used for employing feature level fusion based on features of the shield data to reduce uncertainty,improve accuracy and the data effect,and 9 sets of required principal component characteristic data are *** latter is adopted to process sequence data in predicting the dynamic attitude and position for the advantages and potential of convolution *** approach’s effectiveness is exemplified using data from a tunnel construction project in *** obtained results show remarkable accuracy in predicting the global attitude and position,with an average error ratio of less than 2 mm on four shield outputs in 97.30%of ***,the approach displays strong performance in accurately predicting sudden fluctuations in shield attitude and position,with an average prediction accuracy of 89.68%.The proposed hybrid model demonstrates superiority over TCN,long short-term memory(LSTM),and recurrent neural network(RNN)in multiple *** additive exPlanations(SHAP)analysis is also performed to investigate the significance of different data features in the prediction *** study provides a real-time warning for the shield driver to adjust the attitude and position of super-large diameter shields.

关键词： Shield attitude and position Super-large diameter shield PCA-TCN Deep learning Real-time warning

A semi-analytical model for coupled flow in stress-sensitive multi-scale shale reservoirs with fractal characteristics

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Petroleum Science 2024年第1期21卷 327-342页

作者： Qian Zhang Wen-Dong Wang Yu-Liang Su Wei chen Zheng-Dong lei lei Li Yong-Mao hao Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum(East China)) Ministry of EducationQingdao266580ShandongChina School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongChina Shale Oil Development Branch Changqing Oilfield CompanyPetroChinaQingyang745708GansuChina PetroChina Research Institute of Petroleum Exploration&Development Beijing100083China

A large number of nanopores and complex fracture structures in shale reservoirs results in multi-scale flow of oil. With the development of shale oil reservoirs, the permeability of multi-scale media undergoes changes due to stress sensitivity, which plays a crucial role in controlling pressure propagation and oil flow. This paper proposes a multi-scale coupled flow mathematical model of matrix nanopores, induced fractures, and hydraulic fractures. In this model, the micro-scale effects of shale oil flow in fractal nanopores, fractal induced fracture network, and stress sensitivity of multi-scale media are considered. We solved the model iteratively using Pedrosa transform, semi-analytic Segmented Bessel function, Laplace transform. The results of this model exhibit good agreement with the numerical solution and field production data, confirming the high accuracy of the model. As well, the influence of stress sensitivity on permeability, pressure and production is analyzed. It is shown that the permeability and production decrease significantly when induced fractures are weakly supported. Closed induced fractures can inhibit interporosity flow in the stimulated reservoir volume (SRV). It has been shown in sensitivity analysis that hydraulic fractures are beneficial to early production, and induced fractures in SRV are beneficial to middle production. The model can characterize multi-scale flow characteristics of shale oil, providing theoretical guidance for rapid productivity evaluation.

关键词： Multi-scale coupled flow Stress sensitivity Shale oil Micro-scale effect Fractal theory

Effect of Reclamation on the Groundwater-Lake Water Interaction in chen Lake

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Journal of Earth Science 2024年第3期35卷 1083-1086页

作者： Kun lei Teng Ma Liuzhu chen Zhenxing Li Yu chen School of Environmental Studies State Key Laboratory of Biogeology and Environmental GeologyChina University of GeosciencesWuhan 430078China

0 INTRODUCTION To relieve the short supply of suitable land for residing,cultivating,and commerce,it is accepted to reclaim land from lakes,river estuaries,and coastal regions in many countries(Mancini et al.,2020).The large-scale reclamation activities have an irreversible effect on the mico-geomorphology and hydrodynamic system of seasonally flooded areas(Zhang et al.,2019;Yu et al.,2018).For example,coastal regions reclaimed extended the groundwater flow paths,as well as created groundwater level rise,resulting in water-logging in the reclaimed area(Hu et al.,2008).Similar changes in groundwater flow systems may alter groundwater-lake water interactions,and it can ultimately affect the water cycle in the lake ***,such detailed studies are presently *** addition,natural exchanges between the lake and groundwater systems can be strongly affected by physical hydrological processes(Javadzadeh et al.,2020),chemical properties(Kamtchueng et al.,2015),and bioto behavior(Hancock et al.,2005).

关键词： groundwater coastal logging

Heteroatoms doped iron oxide-based catalyst prepared from zinc slag for efficient selective catalytic reduction of NO_(x) with NH_(3)

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International Journal of Coal Science & Technology 2024年第1期11卷 180-193页

作者： Jiale Liang Yaojun Zhang hao chen Licai Liu Panyang He lei Wu College of Materials Science and Engineering Xi’an University of Architecture and TechnologyXi’an710055China School of Chemistry and Chemical Engineering Xi’an University of Architecture and TechnologyXi’an710055China School of Resources Engineering Xi’an University of Architecture and TechnologyXi’an710055China

Excessive emissions of nitrogen oxides from flue gas have imposed various detrimental impacts on environment,and the development of deNO_(x) catalysts with low-cost and high performance is an urgent *** oxide-based material has been explored for promising deNO_(x) ***,the unsatisfactory low-temperature activity limits their practical *** this study,a series of excellent low-temperature denitrification catalysts(Ha-FeO_(x)/yZS)were prepared by acid treatment of zinc slag,and the mass ratios of Fe to impure ions was regulated by adjusting the acid ***-FeO_(x)/yZS showed high denitrification performance(>90%)in the range of 180–300℃,and the optimal NO conversion and N2 selectivity were higher than 95%at 250℃.Among them,the Ha-FeO_(x)/2ZS synthesized with 2 mol/L HNO3 exhibited the widest temperature window(175–350℃).The excellent denitrification performance of Ha-FeO_(x)/yZS was mainly attributed to the strong interaction between Fe and impurity ions to inhibit the growth of crystals,making Ha-FeO_(x)/yZS with amorphous structure,nice fine particles,large specific surface area,more surface acid sites and high chemisorbed *** in-situ DRIFT experiments confirmed that the SCR reaction on the Ha-FeO_(x)/yZS followed both Langmuir-Hinshelwood(L-H)mechanism and Eley-Rideal(E-R)*** present work proposed a high value-added method for the preparation of cost-effective catalysts from zinc slag,which showed a promising application prospect in NO_(x) removal by selective catalytic reduction with ammonia.

关键词： Flue gas NO_(x)removal Zinc slag-derived catalyst NH_(3)-SCR Catalysis activity

Experimental study on ice monitoring method for 10 kV transmission line with tangent tower in alpine landform

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High Voltage 2024年第1期9卷 182-194页

作者： Lin Yang Zhiqiang chen Yanpeng hao Xinhao Lin lei Yu Yue Li Zhiyong Yuan Licheng Li School of Electric Power South China University of TechnologyGuangzhouChina Electrical Power Research Institute China Southern Power GridGuangzhouChina Electric Power Research Institute of Guizhou Power Grid Co.Ltd. GuizhouChina

Ice monitoring methods were applied for 110 kV and above transmission lines with tangent ***,the change in the vertical span is not considered,and a significant difference lies in the tower-conductor structure of 10 kV transmission *** this reason,a proposal is made about the ice monitoring method for the 10 kV transmission line with tangent tower in alpine landform,which includes the ice monitoring system based on pressure measurement and corresponding equivalent ice thickness calculating *** methods calculate the vertical span under different height difference coefficients.A finite element simulation model and a simulated ice load experiment system are established based on real conductors and *** and simulations under four simulated terrains are conducted within 2.5–20 mm ice thickness *** comparison is made between this method and the method without considering the change in vertical *** results show that the two methods are consistent and the relative errors are lower than�4%in simulation and�10%in experiment when the height difference coefficient is *** it is not 0,the relative errors of this method fall between t0.38%and t6.78%in simulation and−6.40%to t6.60%in experiment,while the relative errors of the method without considering the change in vertical span ranges between−11.13%and−20.23%in simulation and−11.65%to−23.20%in experiment.

关键词： methods tangent method

Research progresses and prospects of multi-sphere compound extremes from the Earth System perspective

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Science China Earth Sciences 2024年第2期67卷 343-374页

作者： Zengchao hao Yang chen College of Water Sciences Beijing Normal UniversityBeijing100875China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing100081China

Compound extremes,whose socioeconomic and ecological impacts are severer than that caused by each event occurring in isolation,have evolved into a hot topic in Earth Science in the past *** the context of climate change,many compound extremes have exhibited increasing frequency and intensity,and shown novel fashions of combinations,posing more pressing demands and tougher challenges to scientific research and disaster prevention and *** article,via a perspective of multi-sphere interactions within the Earth System,systematically reviews the status quo,new scientific understanding,and deficiencies regarding the definition,mechanism,change,attribution,and projection of compound *** study also sorts out existing challenges and outlines a potential roadmap in advancing the study on compound extremes with respect to data requirement,mechanistic diagnosis,numerical modeling,attribution and projection,risk assessment,and adaptive *** directions of compound extremes studies and key research topics that warrant multi-disciplinary and multisectoral coordinated efforts are also *** that climate change has reshaped the type of extremes,a transformation from the traditional single-event perspective to a compound-event perspective is needed for scientific research,disaster prevention and mitigation,and climate change adaptation,calling for bottom-up innovation in research objects,ideas,and *** article will add value to promoting the research on compound extremes and interdisciplinary cooperations.

关键词： Extremes Compound extremes Climate change and risk Multi-sphere interactions

Integrated biomarker response to assess toxic impacts of iron and manganese on deep-sea mussel Gigantidas platifrons under a deep-sea mining activity scenario

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Journal of Oceanology and Limnology 2024年第2期42卷 522-532页

作者： Li ZHOU Mengna LI Zhaoshan ZHONG Minxiao WANG hao chen Chao LIAN hao WANG Huan ZHANG lei CAO Chaolun LI Center of Deep Sea Research Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laoshan Laboratory Qingdao 266237China South China Sea Institute of Oceanology Chinese Academy of SciencesGuangzhou 510301China CAS Key Laboratory of Marine Ecology and Environmental Sciences Institute of OceanologyChinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China

Deep-sea mining activities can potentially release metals,which pose a toxicological threat to deep-sea ***,due to the remoteness and inaccessibility of the deep-sea biosphere,there is insufficient knowledge about the impact of metal exposure on its *** this study,deep-sea mussel Gigantidas platifrons,a commonly used deep-sea toxicology model organism,was exposed to manganese(100,1000μg/L)or iron(500,5000μg/L)for 7 d,*** and iron were chosen for their high levels of occurrence within deep-sea *** accumulation and a battery of biochemical biomarkers related to antioxidative stress in superoxide dismutase(SOD),catalase(CAT),malondialdehyde(MDA);immune function in alkaline phosphatase(AKP),acid phosphatase(ACP);and energy metabolism in pyruvate kinase(PK)and hexokinase(HK)were assessed in mussel *** showed that deep-sea mussel *** exhibited a high capacity to accumulate Mn/*** addition,most tested biochemical parameters were altered by metal exposure,demonstrating that metals could induce oxidative stress,suppress the immune system,and affect energy metabolism of deep-sea *** integrated biomarker response(IBR)approach indicated that the exposure to Mn/Fe had a negative impact on deep-sea mussels,and Mn demonstrated a more harmful impact on deep-sea mussels than ***,SOD and CAT biomarkers had the greatest impact on IBR values in Mn treatments,while ACP and HK were most influential for the low-and high-dose Fe groups,*** study represents the first application of the IBR approach to evaluate the toxicity of metals on deep-sea fauna and serves as a crucial framework for risk assessment of deep-sea mining-associated metal exposure.

关键词： mussel metal deep-sea mining biomarker environmental monitoring