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International Conference on Advanced power System Automation and Protection (APAP)

作者： Fei Xu Bin Wang Xinzhou Dong Runbin Cao Kun Liu Yuelin Yang Tingting Wu State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China College of information and electrical engineering China Agricultural University college of information and electrical engineering China Agricultural University School of Electrical Engineering & Renewable Energy China Three Gorges University Yichang China

The paper mainly focuses on the communication problem based on IEC61850 communication protocol. As in the process level communication system: MU (Merging Unit)-Switch-DIPC (Digital Integrated Protection and control system), the stability of SMV packets transmission is very important. The transmission delay of the process level communication is the key problem that may restrict the protection algorithm and capability. In the meantime, GPS synchronization problem of MUs, protection capability of the integrated protection device and stability of SMV message transmission based on the existing DIPC(DIP-01) system will also be discussed in the paper. Through the experiment and analysis, the paper gives out the key factors that lead to the message transmission delay and packets loss. The work at last gives out some primary ideas to improve the protection capability.

关键词： Random access memory Switches Synchronization Optical fiber devices Delay

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Research on the Impact of Water-Ingression Defects on the Electromagnetic-Thermal Fluctuation and Heat Distribution Characteristics of High Voltage Cable Terminals

SSRN

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SSRN 2023年

作者： Liu, Xingmou Yang, Hui Xu, Qiqi Lin, Haibo Yang, Yongming Jadoon, Ammad Chongqing Key Laboratory of Complex Systems and Bionic Control Chongqing University of Posts and Telecommunications Chongqing400065 China State Key Laboratory of Power Transmission Equipment & System Security and New Technology School of Electrical Engineering Chongqing University Chongqing University Chongqing400044 China NFC-Institute of Engineering &Technology Multan Pakistan

High voltage cable terminals (HVCT) usually work outdoors with water-ingression defect which affects the normal operation of the power system. This paper presents the study of the influence of different water-ingression depth on the temperature distribution of HVCT. Firstly, the model of EM-thermal-fluid coupling field of HVCT was established using finite element method in line with the structural parameters of YJZWC4 HVCT. Subsequently, the effectiveness of the model is then verified by comparing the operation of the model under the actual HVCT. And then, the analysis results of temperature show that the surface temperature of the HVCT at the inlet part is significantly higher than that of the insulating oil part. And The influent depth is positively correlated with surface temperature and temperature gradient. The distortion of the electric field will be more serious due to the deepening of the depth of the inlet water. Finally, the variation of temperature and field strength with the depth of inlet water is summarized by mathematical fitting method. The research results accurately reflect the electromagnetic thermal characteristics of the HVCT under the influent state and provide a reliable technical means for the state prediction and fault diagnosis of the cable terminals. © 2023, The Authors. All rights reserved.

关键词： Atmospheric temperature

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Fuzzy PID controller Optimized by Improved Gravitational Search Algorithm for Load Frequency control in Multi-area power System

IAENG International Journal of Computer Science

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IAENG International Journal of Computer Science 2022年第1期49卷 125-139页

作者： Chen, Gonggui Qin, Feng Long, Hongyu Zeng, Xianjun Kang, Peng Zhang, Jinming Professor of Key Laboratory of Industrial Internet of Things and Networked Control Ministry of Education Chongqing University of Posts and Telecommunications Chongqing400065 China Graduate student of Chongqing University of Posts and Telecommunications Chongqing400065 China Professor level senior engineer of Chongqing Key Laboratory of Complex Systems and Bionic Control Chongqing University of Posts and Telecommunications Chongqing400065 China Senior engineer of State Grid Chongqing Electric Power Company Chongqing400015 China Senior engineer of Economic and Technology Research Institute State Grid Chongqing Electric Power Company Chongqing401120 China

In this paper, an objective function considering performance index and an improved gravitational search algorithm (IGSA) are proposed to optimize the parameters of fuzzy PID (FPID) controller. IGSA is obtained by combining elite strategies and the mining capability of PSO algorithm. The IGSA FPID method which integrates IGSA and FPID controller is tested in a typical two-area non-reheat system, and system responses reflect the advantages of proposed objective function and IGSA. Additionally, the proposed IGSA FPID method still has excellent effects even on the two-area multi-source system with thermal power, hydropower and gas turbines. Meanwhile, the effect of high voltage direct current (HVDC) links in suppressing fluctuations is verified. Due to the popularity of wind power, a novel three-area interconnected power system with nonlinearity connected wind turbine (WT) is designed. Under the control of IGSA FPID, the good stability and dynamic performance of mentioned three-area system are verified. Therefore, FPID controller optimized by IGSA has excellent control effects, stability and universal applicability on the different power systems with multiple area and sources. © 2022. All Rights Reserved.

关键词： Wind turbines

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Short-term PV power prediction model based on weather feature clustering and Adaboost-GA-BP

Short-term PV power prediction model based on weather featur...

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Chinese control and Decision Conference, CCDC

作者： Yujun Liu Xinrui He Shutong Duan Bo Wang Hongqing Wang College of Science Beijing Forestry University Beijing China School of Economics & Management Beijing Forestry University Beijing China State Key Laboratory of Operation and Control of Renewable Energy & Storage Systems China Electric Power Research Institute Beijing China

Based on the weather feature clustering, an optimized algorithm called Adaboost-GA-BP is presented for solving the problem that BP neural network is easy to fall into local extremum and over-fitting in PV power short-term prediction. Initially, the K-means algorithm is applied to cluster the historical data into sunny, cloudy and overcast&rainy day. It is then the GA that optimize initial weights, forming the GA-BP neural network. The idea of Adaboost algorithm is applied to train GA-BP as different weak predictors so that the Adaboost-GA-BP strong predictor is combined. Finally, this paper provides a detailed performances comparison of various models. The Adaboost-GA-BP predicts a 4.4% decrease in MAE and a 4.1% decrease in RMSE for the sunny test set, a 9.0% decrease in MAE and a 13.5% decrease in RMSE for the cloudy test set, and a 2.7% decrease in MAE and a 9.1% decrease in RMSE for the rainy test set, outperforming the BP model, the GA-BP model, and the Adaboost-BP models. After comparative analysis, the model has better prediction accuracy and generalization ability especially for predicting cloudy weather.

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A multi-class pattern recognition method for motor imagery EEG data

A multi-class pattern recognition method for motor imagery E...

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IEEE International Conference on systems, Man and Cybernetics

作者： Yonghui Fang Minyou Chen Robert F Harrison State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China School of Electronic and Information Engineering Southwest University Chongqing China Department of Automatic Control & Systems Engineering University of Sheffield Sheffield UK

The Common Spatial Patterns (CSP) algorithm is useful for calculating spatial filters for detecting event-related desynchronization (ERD) for use in ERD-based brain-computer interfaces (BCIs). However, basic CSP is a supervised algorithm suited only to two-class discrimination; it is unable to solve multiclass discrimination problems. This paper proposes a new method named the binary common spatial patterns (BCSP) algorithm to extend the basic CSP method to multi-class recognition. Our method arranges the spatial filters and Fisher classifiers in the form of a binary tree whereby N - 1 spatial filters and N - 1 Fisher classifiers are calculated for N class recognition. This is fewer than must be calculated in other methods (e.g. one-versus-rest, OVR). This makes the overall classification procedure less redundant. simulation results show that BCSP has better performance than the OVR scheme and outperforms the three best teams in the 2008 BCI-competition.

关键词： Spatial filters Arrays Feature extraction Electroencephalography Band pass filters Covariance matrix Filtering algorithms

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A transient damping method of virtual synchronous generators for synchronization stability enhancement

A transient damping method of virtual synchronous generators...

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12th International Conference on Renewable power Generation (RPG 2023)

作者： H. Diao J. Zhang J. Xu W. Dong J. Kang Z. Ling College of Automation Engineering Nanjing University of Aeronautics and Astronautics Nanjing People's Republic of China State Key Laboratory of Operation and Control of Renewable Energy & Storage Systems (China Electric Power Research Institute) Beijing People's Republic of China

The virtual synchronous generator (VSG) which can emulate the typical synchronous generator (SG) dynamic has been used to improve the dynamic performance and stability of inverter-based resources (IBRs). However, VSG can encounter the large-disturbance instability during grid voltage fluctuations or faults. During the transient, the power angle of VSG may overshoot or even diverge due to the poor damping, and VSG may still lose the synchronization with the grid and become unstable if the transient damping is insufficient, despite the existence of equilibrium points. Hence, it is of vital importance to improve the damping and stability of VSG during the transient. Therefore, this study aims to propose a transient stability enhancement method for VSG. The technique of three consecutive sampling points (3CS) is utilized for frequency detection, and an additional branch from the output of 3CS is added in the active power control loop. It will be shown that the VSG employing such method behaves satisfactory transient damping while the steady-state behaviour is hardly affected. Detailed theoretical stability analysis and simulation results are provided to demonstrate the effectiveness of the proposed method.

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Aggregation reduced-order modeling of grid-connected multi-converter system for transient stability analysis

Aggregation reduced-order modeling of grid-connected multi-c...

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12th International Conference on Renewable power Generation (RPG 2023)

作者： Z. Ling Z. Chen J. Xu Y. Shi College of Automation Engineering Nanjing University of Aeronautics and Astronautics Nanjing People's Republic of China State Key Laboratory of Operation and Control of Renewable Energy & Storage Systems (China Electric Power Research Institute) Beijing People's Republic of China

Under large disturbances (e.g., grid sag, power step), the grid-connected system using phase-locked loop (PLL) as the synchronization unit is easy to lose the synchronization so that the transient stability is endangered. In order to facilitate the integration of large-scale renewable energies, it is very important to precisely examine the stability of grid-connected multi-converter system under large disturbances. As proved, the system transient stability depends on the converter with the worst stability (named as the critical converter) in the system. However, the judgment of critical converter is a complex and time-consuming task for multi-converter system. In this study, in order to simplify the transient stability analysis and quickly examine the multi-converter system, an aggregation reduced-order model based on averaging the impedance voltage drop is established. The reduced-order inverter and its aggregated parameters for representing the multi-converter system are obtained. Then, the transient stability of the system represented by the aggregation reduced-order model is compared to the original full-order system. Finally, the accuracy of the model is verified by simulations.

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Optimal operation of microgrids with risk-constrained state of charge

Optimal operation of microgrids with risk-constrained state ...

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European control Conference (ECC)

作者： Jie Lei Christian A. Hans Pantelis Sopasakis State Key Laboratory of Power Transmission Equipment & System Security and New Technology at Chongqing University China Control Systems Group at Technische Universität Berlin Germany School of EEECS and the i-AMS Centre at Queen’s University Belfast UK

In this paper we present a stochastic scenario-based model predictive control (MPC) approach for the operation of islanded microgrids with high share of renewable energy sources. We require that the stored energy remains within given bounds with a certain probability using risk-based constraints as convex approximations of chance constraints. We show that risk constraints can generally be cast as conic constraints and, unlike chance constraints, can control both the number and average magnitude of constraint violations. Lastly, we demonstrate the risk-constrained stochastic MPC in a numerical case study.

关键词： Renewable energy sources Costs Stochastic processes Europe Microgrids state of charge Frequency control

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MARS: Multi-Agent Deep Reinforcement Learning for Real-Time Workflow Scheduling in Hybrid Clouds with Privacy Protection

MARS: Multi-Agent Deep Reinforcement Learning for Real-Time ...

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International Conference on Parallel and Distributed systems (ICPADS)

作者： Long Cheng Haoyang He Yan Gu Qingzhi Liu Zhiming Zhao Fang Fang State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources School of Control and Computer Engineering North China Electric Power University Beijing China Information Technology Group Wageningen University and Research Netherlands Research Group of Multi-Scale Networked Systems University of Amsterdam Netherlands

ISBN: (数字)9798331515966

ISBN: (纸本)9798331515973

Scheduling workflows in hybrid cloud environments presents significant challenges due to the inherent complexity of workflows and the dynamic nature of cloud resources. This complexity is further increased when attempting to balance workflow performance with privacy protection. Recent efforts have leveraged deep reinforcement learning (DRL) to address these challenges. However, most of these approaches rely on single-agent models, which can lead to security issues and scalability problems due to their centralized processing. Specifically, the properties of workflows are transferred to the single agent, which risks leaking privacy information. Our paper addresses these issues by introducing MARS, a real-time workflow scheduling method that prioritizes privacy protection in hybrid clouds. MARS leverages multi-agent deep reinforcement learning (MADRL) to optimize the workflow scheduling of cloud virtual machines (VMs). The benefit of our solution is that it relies on the collaborative learning of multi-agents on multiple VMs, which could assign user data to specific cloud servers for privacy protection while sharing training experiences between agents. In our implementation, MARS aims to reduce workflow completion time and operational costs while complying with strict privacy protection guidelines. The experimental results demonstrate that MARS can significantly surpass existing methods, reducing makespan by an average of $53.18 \%$ and costs by $61.98 \%$ compared to basic techniques, and achieving $20.26 \%$ and $25.71 \%$ improvements over the latest advanced methods, respectively.

关键词： Training Cloud computing Privacy Costs Scalability Deep reinforcement learning Dynamic scheduling Real-time systems Complexity theory Protection

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Particle-Scale Modelling of Injected Hydrogen and Coke Co-Combustion in the Raceway of an Ironmaking Blast Furnace

SSRN

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SSRN 2022年

作者： Dianyu, E. Zhou, Peng Ji, Langyong Cui, Jiaxin Xu, Qiang Guo, Liejin Yu, Aibing International Institute for Innovation Jiangxi University of Science and Technology Ganzhou341000 China Jiangxi Provincial Key Laboratory for Simulation and Modelling of Particulate Systems Jiangxi University of Science and Technology Ganzhou341000 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China ARC Research Hub for Computational Particle Technology Department of Chemical Engineering Monash University VIC3800 Australia Centre for Simulation and Modelling of Particulate Systems Southeast University Monash University Joint Research Institute Suzhou215123 China

Hydrogen is an environmentally friendly fuel that does not produce greenhouse gas (GHG) emissions. Its applications have attracted significant attention from many industries, especially the ironmaking industry, which consumes massive amounts of fossil energy. The injection of hydrogen into a blast furnace (BF) is one of the most promising low-carbon ironmaking routines. In this study, an experimentally validated CFD-DEM model is adopted to investigate the dynamics, microstructure and thermochemical behaviours in the raceway of a BF with hydrogen injection operations (HIOs), which include raceway evolution, force distribution and the co-combustion characteristics of hydrogen and coke. Some significant features are obtained through comparison analyses between HIOs and air injection operations (AIOs). In particular, the effects of the hydrogen injection concentration on the raceway size, gas temperature and components are studied. The simulation results show that a smaller raceway is formed under HIOs in comparison with that of AIOs. In addition, the gas temperature is higher near the tuyere but lower along the tuyere axis, and the oxygen consumption is larger and produces more CO. As the hydrogen injection concentration increases: (i) the raceway size and gas temperature decrease;(ii) the CO is generated at the early stage and the maximum CO2 concentration moves to inlet direction along the tuyere axis. The results provide insights on the fundamental understanding of low-carbon ironmaking BF technology. © 2022, The Authors. All rights reserved.

关键词： Blast furnaces

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