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Surface-enhanced Raman scattering for mixing state characterization of individual fine particles during a haze episode in Beijing,China

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Journal of Environmental Sciences 2021年第6期33卷 216-224页

作者： Hui Chen Fengkui Duan Jingjing Du Ranhao Yin Lidan Zhu Jinlu Dong Kebin He Zhenli Sun Suhua Wang MOE Key Laboratory of Resources and Environmental System Optimization College of Environmental Science and EngineeringNorth China Electric Power UniversityBeijing 102206China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Guangdong Provincial Key Laboratory of Petrochemcial Pollution Processes and Control School of Environmental Science and EngineeringGuangdong University of Petrochemical TechnologyMaoming 525000China

The nondestructive characterization of the mixing state of individual fine particles using the traditional single particle analysis technique remains a *** this study,fine particles were collected during haze events under different pollution levels from September 5 to 112017 in Beijing,China.A nondestructive surface-enhanced Raman scattering(SERS)technique was employed to investigate the morphology,chemical composition,and mixing state of the multiple components in the individual fine *** image and SERS spectral analysis results show that soot existing in the form of opaque material was predominant during clear periods(PM_(2.5)≤75μg/m^(3)).During polluted periods(PM_(2.5)>75μg/m^(3)),opaque particles mixed with transparent particles(nitrates and sulfates)were generally *** classical least squares analysis further identified the relative abundances of the three major components of the single particles:soot(69.18%),nitrates(28.71%),and sulfates(2.11%).A negative correlation was observed between the abundance of soot and the mass concentration of PM_(2.5).Furthermore,mapping analysis revealed that on hazy days,PM_(2.5)existed as a core-shell structure with soot surrounded by nitrates and *** mixing state analysis method for individual PM_(2.5)particles provides information regarding chemical composition and haze formation mechanisms,and has the potential to facilitate the formulation of haze prevention and control policies.

关键词： PM_(2.5) Surface-enhanced Raman scattering Individual fine particle Nitrate Sulfate Soot

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SiC MOSFET Crosstalk Modelling with Suppression Considering Impacts of dv/dt and di/dt

SiC MOSFET Crosstalk Modelling with Suppression Considering ...

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International Conference on power Electronics (ICPE)

作者： Wenhao Xie Shiqi Ji Zhengming Zhao Xin Mo Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University China Tsinghua Sichuan Energy Internet Research Institute China

Compared to Si IGBTs, SiC MOSFETs can reduce switching losses, achieve higher switching frequencies and enable smaller converter size. However, due to the high dv/dt of SiC MOSFETs, certain topologies, such as two SiC MOSFETs in a phase-leg configuration, are highly sensitive to crosstalk, which can slow down switching speed and even reduce gate oxide’s lifetime. In this paper, an accurate model of crosstalk is established by considering the impacts of both dv/dt and di/dt in the power loop. The proposed model can simulate the gate-source voltage on bare die of SiC MOSFETs, allowing for a more accurate evaluation of the impact of crosstalk. Model verification is implemented using a double pulse test (DPT) platform and a gate driver with active miller clamp technology. key parameters of the model are extracted from both 3D simulation models and measurement experiments. The DPT waveform of power loop is used as the excitation source in the simulation, and the simulated gate-source waveform shows good agreement with the experimental waveform. Based on the model, parameter sensitivity analysis is performed, and suggestions for improving crosstalk suppression are proposed.

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Critical link identification of power system vulnerability based on modified graph attention network

arXiv

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arXiv 2024年

作者： Wang, Changgang Wang, Xianwei Cao, Yu Li, Yang Lü, Qi Zhang, Yaoxin Key Laboratory of Modern Power System Simulation and Control and Renewable Energy Technology Ministry of Education Northeast Electric Power University Jilin132012 China Northeast Electric Power University Jilin132012 China State Grid Tianjin Electric Power Company Tianjin300010 China

As the power grid expands and the proportion of renewable energy increases, the uncertainty and randomness of the power grid have increased, posing a threat to the security of system operation. It becomes crucial to identify the crucial links in the power grid to ensure its reliability during operation. Addressing the issues of slow identification speed and difficulty in meeting the actual operational requirements of traditional methods for identifying crucial links in the power grid, this paper proposes a method based on the Modified Graph Attention Network (MGAT) algorithm for identifying crucial link in the power grid. Firstly, combining complex network theory with actual power grid operational data, an evaluation index set is established. Subsequently, the MGAT is utilized to explore the mapping relationships between various indicators during power grid operation and the crucial links, forming a model for crucial link identification. Considering the requirements of training accuracy and efficiency, the original data is preprocessed to optimize the model. Next, through simulation, the original dataset is obtained for training, validation, and testing of the identification model. Finally, the proposed model is applied to an improved IEEE 30-node system and a real power grid. The results indicate the feasibility of the proposed method, with accuracy and speed surpassing traditional methods, demonstrating its practical engineering value. © 2024, CC BY-NC-ND.

关键词： Smart power grids

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Active Dynamic Aggregation Model for Distributed Integrated Energy system as Virtual power Plant

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Journal of Modern power systems and Clean Energy 2020年第5期8卷 831-840页

作者： Haotian Zhao Bin Wang Xuanyuan Wang Zhaoguang Pan Hongbin Sun Zhen Liu Qinglai Guo State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical EngineeringTsinghua UniversityBeijingChina State Grid Jibei Electric Power Co. Ltd.BeijingChina

Distributed integrated multi-energy systems(DIMSs)can be regarded as virtual power plants to provide additional flexibility to the power *** paper proposes a robust active dynamic aggregation model for the DIMSs to describe the maximum feasible *** aggregation model includes the power constraints,energy constraints,and ramping constraints to aggregate different types of resources in the *** proposed generator-like and storage-like model does not depend on the ancillary service market and can be directly incorporated into the economic dispatch model of the power system.A novel algorithm based on the column-and-constraint generation algorithm and convex-concave procedure is proposed to solve the two-stage robust optimization problem,which is more efficient than the KKT-based ***,a case study of an actual DIMS is developed to demonstrate the effectiveness of the proposed model.

关键词： Aggregation distributed integrated energy system(DIMS) robust optimization virtual power plant

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Evaluation of Regulating Capacity of power system Nodes and Transmission Lines

Evaluation of Regulating Capacity of Power System Nodes and ...

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Smart Grid and Artificial Intelligence (SGAI), International Conference on

作者： Xiuyu Yang Zekun Fan Almasbek Shakenbek Baoyu Di Chongbi Li Yi Wang Key Laboratory of Modern Power System Simulation Control and New Green Energy Technology of Ministry of Education Northeasst Electric Power University Jilin China State Grid Xinjiang Electric Power Co. Ltd. State Grid Xinjiang Electric Power Co. Ltd. Electric Power Research Institute Urumqi China

ISBN: (数字)9798331518806

ISBN: (纸本)9798331518813

The large-scale access of renewable energy to the power grid leads to a sharp increase in the demand for power system regulation capacity. In order to solve this problem, this paper explores the mechanism of supply and demand balance of power system regulation capacity, analyzes the transmission characteristics of regulation capacity, and proposes the adequacy index of node regulation capacity and the adequacy index of network transmission regulation capacity. The Garver-6 node system is used to verify the effectiveness and practicability of the proposed method. The example shows that the proposed evaluation method can accurately identify the weak links of regulation ability and clarify the causes of insufficient regulation ability.

关键词： Renewable energy sources Supply and demand power transmission lines Evaluation models Regulation Smart grids Planning Artificial intelligence Load flow Capacity planning

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Cooperative control Strategy of Regional Energy Storage and Thermal power Generation Considering Frequency Dynamic Response

Cooperative Control Strategy of Regional Energy Storage and ...

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power and Electrical Engineering (ACPEE), 5th Asia Conference on

作者： Junhui Li Zhenbo Yu Yang Zhao Jie Ma Xiaoliang Jiang Haozheng Yu Xingxu Zhu Cuiping Li Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology Northeast Electric Power University Jilin China Development Planning Department State Grid Henan Electric Power Company Zhengzhou China Planning and Assessment Centre State Grid Henan Electric Power Company Zhengzhou China

ISBN: (数字)9798350309638

ISBN: (纸本)9798350309645

With the continuous promotion of the goal of “carbon peak, carbon neutral”, China is building a new type of power system in which the proportion of wind power/photovoltaic energy is gradually increasing, but the scenario of a high proportion of renewable energy will also bring the overall system frequency regulation pressure due to the shortage of frequency modulation(FM) capacity and other problems. This paper firstly quantifies the system frequency dynamic response(FDR) modeling under the scenario of high proportion of renewable energy, and derives the expression of the system overall frequency fluctuation characteristics; then according to the quantitative analysis results, it proposes the strategy of coordinating the conventional thermal power units with regional energy storage (ES) for joint frequency regulation, combining with regional ES for fast regulation and bidirectional response to meet the demand of system frequency regulation; finally, it carries out the case study with the northwestern regional grid, and the results show that the system frequency regulation reasonably meets the operational requirements and accurately verifies the validity of the proposed strategy.

关键词： Renewable energy sources Frequency modulation Wind energy Statistical analysis power system dynamics Thermal engineering Thermal analysis

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Generation method of anti-misoperation locking logic rules for substations based on typical wiring

Generation method of anti-misoperation locking logic rules f...

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

作者： Jingxiang Zhang Hui Zou Hewei Hou Junhui Li Rongrong Ji Kaiyuan Duan Cuiping Li Xingxu Zhu Extra-High Voltage Branch Company of State Grid Zhejiang Electric Power Co. Ltd Hangzhou China Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology Ministry of Education Northeast Electric Power University Jilin China

ISBN: (数字)9798331523527

ISBN: (纸本)9798331523534

At present, substations usually use electrical blocking facilities to achieve the function of anti-fault blocking, but new stations and new reconstruction and expansion stations have the problem of low efficiency in the compilation and review of anti-fault blocking logic rules, and also need a lot of manual debugging and checking time. In this paper, based on the typical substation wiring and anti-false blocking logic rules, the typical substation wiring library and the corresponding blocking logic library are constructed; then, the graphic editing module and graphic analysis module are constructed by combining the substation modelling method with the topology and other technologies. Finally, the automatic generation of anti-error latching logic rules is realised, which solves the problems of low efficiency and lack of reliability in the writing and checking of the corresponding substation anti-misoperation locking logic rules.

关键词： Wiring Graphics Substations Reviews Debugging system integration Libraries Topology Logic Reliability

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Capacitor Voltage Balancing Strategy Based on Zero-Sequence Voltage Injection for Half-Wave Commutated Modular Multilevel Converter

Capacitor Voltage Balancing Strategy Based on Zero-Sequence ...

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International Conference on power Electronics and Motion control (IPEMC)

作者： Nan Fu Bao Liu Yunfei Xu Sitong Zhu Kui Wang Yongdong Li Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China State Key Laboratory of Advanced Power Transmission Technology State Grid Smart Grid Research Institute Co. Ltd Changping Beijing China Electric Power Research Institute of State Grid Liaoning Electric Power Co. Ltd. Shenyang China

ISBN: (数字)9798350351330

ISBN: (纸本)9798350351347

Half-wave commutated modular multilevel converter (HWC-MMC) is suitable for high-voltage large-capacity AC-AC conversion, and an appropriate capacitor voltage balancing strategy is essential. This paper analyzes the condition of capacitor voltage balancing and proposes a capacitor voltage balancing strategy based on optimal zero-sequence voltage injection using the model predictive control. Finally, the simulation is carried out to verify the proposed strategy.

关键词： Multilevel converters Voltage fluctuations Capacitors High-voltage techniques power system harmonics power electronics Steady-state

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Ultra-Short-Term Wind power Interval Prediction Based on Fluctuating Process Partitioning and Quantile Regression Forest

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FRONTIERS IN ENERGY RESEARCH 2022年 10卷

作者： Sun, Yong Huang, Yutong Yang, Mao Key Laboratory of Modern Power System Simulation and Control and Renewable Energy Technology Ministry of Education (Northeast Electric Power University) Jilin China State Grid Jilin Electric Power Company Ltd. Changchun China

As errors in point forecasts of wind power are unavoidable, interval forecasts can adequately describe the uncertainty in wind power and thus provide further guidance to dispatchers in their decision making. Current interval prediction methods are still incomplete in terms of tapping into the physical variability of wind power, especially for the specific time scale of the ultra-short term. This paper therefore proposes a new framework for interval forecasting of ultra-short-term wind power that incorporates the power fluctuation process. Firstly, a fluctuating process of wind power series is defined and a Kalman-SOM method for clustering the fluctuating processes of wind power is constructed. Secondly, a quantile regression forest interval prediction model is constructed for multiple fluctuation processes for ultra-short-term time scales. Finally, the effectiveness of the overall framework is validated at a wind farm in Jilin Province, China. Compared with the traditional interval prediction method. The interval bandwidth is reduced by 0.86% on average, and the interval coverage is increased by 1.4% on average. The results demonstrate the effectiveness and feasibility of the method in this paper.

关键词： wind power ultra-short-term prediction self-organizing map fluctuation quantile regression forest

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Long-Foresight-Term power Prediction Considering the Evolution of Significant Weather Information for Wind Farm Cluster

SSRN

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SSRN 2023年

作者： Yang, Mao Jiang, Renxian Zhang, Xiaobin Huang, Yutong Guo, Yunfeng Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology Ministry of Education Northeast Electric Power University Jilin132012 China State Grid Gansu Electric Power Company Gansu730030 China

The current wind power prediction horizon extends up to 7 days, and the research on power prediction for the 8 to 15 day-ahead is still lacking. However, with the increasing proportion of renewable energy in novel power systems, breaking through the long-foresight-term power prediction barrier is crucial support for guaranteeing the secure and stable operation of the power system. To address the aforementioned issues, this study presents a power prediction method for wind farm cluster (WFC) in long-foresight-term, based on the poor availability of existing numerical weather prediction (NWP) in long-foresight-term. Firstly, a significant wind process identification method considering autocorrelation analysis is employed to predict future power trends, and an optimal method is explored for power generation (PG) prediction in the 8 to 15 day-ahead. Secondly, under the constraint of predicted PG, the power corresponding to the historical similar wind process is selected as the predicted value. Finally, the proposed methodology is applied to a WFC in Gansu Province, China. The results indicate that the proposed method reduces the average RMSE and MAE by 4.15% and 3.3%, respectively, effectively tracking the changing trends of wind power. Moreover, it achieves long-foresight-term prediction and enhances the reliability of the prediction. © 2023, The Authors. All rights reserved.

关键词： Numerical methods

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