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arXiv 2020年

作者： Qiu, Yiwei Lin, Jin Liu, Feng Dai, Ningyi Song, Yonghua Chen, Gang Ding, Lijie State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100087 China State Key Laboratory of Internet of Things for Smart City University of Macau 999078 China State Grid Sichuan Electric Power Research Institute Chengdu610000 China

To enable power supply in rural areas and to exploit clean energy, fully renewable power systems consisting of cascaded run-of-the-river hydropower and volatile energies such as pv and wind are built around the world. In islanded operation mode, the primary and secondary frequency control, i.e., hydro governors and automatic generation control (AGC), are responsible for the frequency stability. However, due to limited water storage capacity of run-of-the-river hydropower and river dynamics constraints, without coordination between the cascaded plants, the traditional AGC with fixed participation factors cannot fully exploit the adjustability of cascaded hydropower. When imbalances between the volatile energy and load occur, load shedding can be inevitable. To address this issue, this paper proposes a coordinated tertiary control approach by jointly considering power system dynamics and the river dynamics that couples the cascaded hydropower plants. The timescales of the power system and river dynamics are very different. To unify the multi-timescale dynamics to establish a model predictive controller that coordinates the cascaded plants, the relation between AGC parameters and turbine discharge over a time interval is approximated by a data-based second-order polynomial surrogate model. The cascaded plants are coordinated by optimising AGC participation factors in a receding-horizon manner, and load shedding is minimised. simulation of a real-life system with real-time pv data collected on site shows the proposed method significantly reduces load loss under pv volatility. Copyright © 2020, The Authors. All rights reserved.

关键词： Electric load shedding

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Nonintrusive uncertainty quantification of dynamic power systems subject to stochastic excitations

arXiv

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arXiv 2020年

作者： Qiu, Yiwei Lin, Jin Chen, Xiaoshuang Liu, Feng Song, Yonghua State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100087 China Department of Electrical and Computer Engineering University of Macau 999078 China Department of Electrical Engineering Tsinghua University Beijing100087 China

Continuous-time random disturbances (also called stochastic excitations) due to increasing renewable generation have an increasing impact on power system dynamics;However, except from the Monte Carlo simulation, most existing methods for quantifying this impact are intrusive, meaning they are not based on commercial simulation software and hence are difficult to use for power utility companies. To fill this gap, this paper proposes an efficient and nonintrusive method for quantifying uncertainty in dynamic power systems subject to stochastic excitations. First, the Gaussian or non-Gaussian stochastic excitations are modeled with an Itô process as stochastic differential equations. Then, the Itô process is spectrally represented by independent Gaussian random parameters, which enables the polynomial chaos expansion (PCE) of the system dynamic response to be calculated via an adaptive sparse probabilistic collocation method. Finally, the probability distribution and the high-order moments of the system dynamic response and performance index are accurately and efficiently quantified. The proposed nonintrusive method is based on commercial simulation software such as PSS/E with carefully designed input signals, which ensures ease of use for power utility companies. The proposed method is validated via case studies of IEEE 39-bus and 118-bus test *** codes 93E10 Copyright © 2020, The Authors. All rights reserved.

关键词： Uncertainty analysis

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From Distributed Energy Resources to Virtual Power Plants: A Cyber-Physical System Solution for Integrating Demand-side in Smart Grid

From Distributed Energy Resources to Virtual Power Plants: A...

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

作者： Liting Tian Lin Cheng Yuxiang Wan Kai Yuan Rui Liu Kuihua Wu State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China State Grid Economic & Technology Research Institute Beijing China Economic & Technology Research Institute State Grid Shandong Electric Power Company Jinan China

ISBN: (数字)9781728196060

ISBN: (纸本)9781728196077

Distributed Energy Resources(DERs) will be an important part of the future power system under the spread of distributed renewable energy generation, electric vehicles, demand response and other technologies. Cyber-physical system (CPS) is one of the development directions for the future smart grid to integrate the widespread DERs. First, this paper presents the basic architecture and operation process of virtual power plant (VPP). Then the solution of communication structure and software platform are proposed. It is pointed out that virtual power plants have good applicability in information and communication infrastructure, power market and DER integration. Finally, a demonstration program in China is introduced. The research and application of virtual power plant is currently in its embryonic form. It provides a solution for the transmission from centralized power production to the distributed energy utilization, and is an adequate way to integrate geographical dispersion, heterogeneous DERs.

关键词： Renewable energy sources Transforms System integration Cyber-physical systems Power markets Software Smart grids

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基于纳米金/介孔NiO/泡沫镍纳米复合材料的微型电极用于地下水重金属检测（英文）

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Engineering 2023年第8期 199-208页

作者： Boyuan Xue Qian Yang Kaidong Xia Zhihong Li George Y.Chen Dayi Zhang Xiaohong Zhou State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University National Key Laboratory of Science and Technology on Micro/Nano Fabrication Institute of Microelectronics Peking University Shenzhen Key Laboratory of Photonic Devices and Sensing Systems for Internet of Things Guangdong and Hong Kong Joint Research Centre for Optical Fiber SensorsShenzhen University College of New Energy and Environment Jilin University The Research Institute of Environmental Innovation (Suzhou) Tsinghua University

Heavy metals, notably Pb2+and Cu2+, are some of the most persistent contaminants found in groundwater. Frequent monitoring of these metals, which relies on efficient, sensitive, cost-effective, and reliable methods, is a necessity. We present a nanocomposite-based miniaturized electrode for the concurrent measurement of Pb2+and Cu2+by exploiting the electroanalytical technique of square wave *** also propose a facile in situ hydrothermal calcination method to directly grow binder-free mesoporous Ni O on a three-dimensional nickel foam, which is then electrochemically seeded with gold nanoparticles（Au NPs）. The meticulous design of a low-barrier Ohmic contact between mesoporous Ni O and Au NPs facilitates target-mediated nanochannel-confined electron transfer within mesoporous Ni O. As a result, the heavy metals Pb2+(0.020 mg.L-1detection limit; 2.0–16.0 mg.L-1detection range)and Cu2+(0.013 mg.L-1detection limit; 0.4–12.8 mg.L-1detection range) can be detected simultaneously with high precision. Furthermore, other heavy metal ions and common interfering ions found in groundwater showed negligible impacts on the electrode's performance, and the recovery rate of groundwater samples varied between 96.3% ± 2.1% and 109.4% ± 0.6%. The compactness, flexible shape, low power consumption, and ability to remotely operate our electrode pave the way for onsite detection of heavy metals in groundwater, thereby demonstrating the potential to revolutionize the field of environmental monitoring.

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State estimation for a class of linear systems with quadratic output

arXiv

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arXiv 2020年

作者： Theodosis, Dionysios Berkane, Soulaimane Dimarogonas, Dimos V. Dynamic Systems and Simulation Laboratory School of Production Engineering and Management Technical University of Crete Greece Département d’informatique et d’ingénierie Université du Québec en Outaouis GatineauQC Canada Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Sweden

This paper deals with the problem of state estimation for a class of linear time-invariant systems with quadratic output measurements. An immersion-type approach is presented that transforms the system into a state-affine system by adding a finite number of states to the original system. Under suitable persistence of excitation conditions on the input and its higher derivatives, global state estimation is exhibited by means of a Kalman-type observer. A numerical example is provided to illustrate the applicability of the proposed observer design for the problem of position and velocity estimation for a vehicle navigating in the n−dimensional Euclidean space using a single position range measurement. Copyright © 2020, The Authors. All rights reserved.

关键词： State estimation

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An Explicit MPC Based on Galerkin Method for AGC Considering Volatile Generations

An Explicit MPC Based on Galerkin Method for AGC Considering...

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IEEE Power and Energy Society General Meeting

作者： Yiwei Qiu Jin Lin Feng Liu Yonghua Song State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China The University of Macau Macau China

Imbalance of generation and load caused by volatile generations poses challenges on frequency regulation. AGC is required to respond to the generation fluctuations without violating operational and security constraints. While explicit model predictive control (EMPC) provides an approach, the partition number of the piecewise affine control laws grows exponentially with the number of constraints and prediction/control horizons, which hinders its application in large systems. In this paper, we propose an EMPC approach for AGC by approximating the control laws using Legendre polynomial series expansions, thus entirely eliminating the partition issue. Galerkin method is applied to the KKT conditions of EMPC's multiparametric quadratic programming (mp-QP) problem to compute the approximations. Case study in New England 39-bus system verifies the performance and efficiency of the proposed controller.

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Electron relaxation properties of Ar magnetron plasmas

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Plasma Science and Technology 2018年第3期20卷 87-94页

作者： Xinjing CAI Xinxin WANG Xiaobing ZOU Department of Electrical Engineering Northeast Electric Power UniversityJilin 132012People's Republic of China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua UniversityBeijing 100084People's Republic of China

An understanding of electron relaxation properties in plasmas is of importance in the application of *** improved multi-term approximation of the Boltzmann equation is employed to study electron transport and relaxation properties in ***,inelastic and nonconservative collisions between electrons and neutral particles are *** expressions for the transport coefficients are obtained using the expansion coefficients and the collision operator *** solutions of the matrix equations for the expansion coefficients are also *** calculations of the Reid model are presented to demonstrate the accuracy of the improved multi-term *** is shown that the twoterm approximation is generally not accurate enough and the magnetic fields can reduce the anisotropy of the velocity distribution *** electron relaxation properties of Ar plasmas in magnetrons for various magnetic fields are *** is demonstrated that the energy parameters change more slowly than the momentum parameters.

关键词： electron transport electron relaxation Boltzmann equation multi-term approximation

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Multi-channel attention mechanism graph convolutional network considering cumulative effect and temporal causality for day-ahead wind power prediction

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Energy 2025年 332卷

作者： Mao Yang Renxian Jiang Bo Wang Guozhong Fang Yunpeng Jia Fulin Fan Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology Ministry of Education (Northeast Electric Power University) Jilin 132012 China State Key Laboratory of Operation and Control of Renewable Energy & Storage Systems China Electric Power Research Institute Beijing 100912 China State Grid Corporation of China Northeast Branch Liaoning 100031 China Grid Jilin Electric Power Co. Ltd. Jilin Power Supply Company of State Jilin 130021 China School of Electrical Engineering and Automation Harbin Institute of Technology Harbin 150001 China Institute for Energy and Environment University of Strathclyde Glasgow G1 1XW UK

Under the current situation where the proportion of wind power generation in the existing energy structure is gradually increasing, accurate short-term power prediction of wind farm cluster (WFC) plays an important auxiliary role in the formulation of regional power generation plans. However, it is difficult to clarify the correlation between wind farms in the power prediction of WFC, which leads to the difficulty of stable and accurate prediction. Therefore, this paper proposes a short-term power prediction method for WFC considering wind power cumulative effect (CE) and temporal causality (TC). Firstly, the two relationships (CE and TC) between wind farms are clarified and used to construct an adjacency matrix separately, then the error characteristics (EC) are used to form an adjacency matrix as well. Secondly, the adjacency matrix information with different attributes is fused by the multi-channel attention mechanism to obtain the wind power prediction results. Finally, the proposed method is applied to three WFCs in China, by which the universality and effectiveness of the method is verified. Compared with the traditional prediction method, its RMSE is reduced by 1.55 %, 1 % and 3.4 % on average.

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Influence of remelting sequence on defect generation and high-temperature mechanical properties in laser powder bed fusion of IN718 alloys

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Additive Manufacturing 2025年

作者： Fuzhong Chu Shun Wu Haopeng Shen Hongyu Yan Yaping Wu Xianfa Xu Hao Zhang Aijun Huang Ruiping Zou Xinhua Wu Zongyan Zhou ARC Research Hub for Smart Process Design and Control Department of Chemical and Biological Engineering Monash University Clayton VIC 3800 Australia Monash Centre for Additive Manufacturing Monash University Notting Hill VIC 3168 Australia School of Iron and Steel Soochow University Suzhou 215021 China Jiangxi Provincial Key Laboratory for Simulation and Modelling of Particulate Systems Jiangxi University of Science and Technology Nanchang Campus Jiangxi 330013 China Faculty of Materials and Manufacturing Beijing University of Technology Beijing China

The laser multiple melting strategy is commonly employed in the laser powder bed fusion (LPBF) process to reduce porosity levels and optimize mechanical properties. However, the influence of the temporal sequences of energy input has received limited attention, despite their potential to control defect generation and microstructure evolution. Therefore, in this work, two specific remelting sequences were investigated, referred to here as the preheating strategy (a low-energy first scan followed by a high-energy second scan) and the remelting (a high-energy first scan followed by a low-energy second scan) strategy. The findings indicated that defect generation and surface roughness are highly sensitive to variations in the remelting sequences, demonstrating that samples subjected to the remelting strategy exhibit significantly lower porosity levels. The simulations revealed that the defects in the preheating strategy originate from insufficient melting between layers and rough top surfaces caused by inadequate melt pool flow. Additionally, the samples subjected to the remelting strategy exhibited superior high-temperature mechanical properties, with an ultimate tensile strength of 959.7 MPa, yield strength of 792 MPa, and outstanding elongation of 23.1% along the building direction after heat treatment. This enhancement was attributed to the increased geometrically necessary dislocation density induced by fine carbides measuring 0.9 μm. This study offers valuable insights into the laser multiple melting process, providing a foundation for future research aimed at optimizing mechanical properties in the LPBF process.

关键词： laser powder bed fusion remelting sequence defect generation simulation high-temperature mechanical property

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Investigation on Insulating Properties of Epoxy Resin Impregnated Paper Affected by Curing Agents and Accelerator Contents

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IEEE Transactions on Dielectrics and Electrical Insulation 2025年

作者： Teng, Chenyuan Ding, Yichao Zhou, Yuanxiang Zhao, Lei Zhang, Yunxiao Chen, Haoran Zhang, Youbing Zhejiang University of Technology College of Information Engineering Hangzhou310023 China Nankai University China and College of Electronic Information and Optical Engineering Tianjin300350 China Zhejiang Testing & Inspection Institute for Mechanical and Electrical Products Quality Co. Ltd Hangzhou310051 China Tsinghua University State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Beijing100084 China State Grid Xinxiang Electric Power Supply Company Xinxiang453002 China

The curing formula is vital to the performance of epoxy resin impregnated paper (RIP) material. This work explored the effect of curing agents and accelerator contents on the thermal and electrical properties of RIP material. It was found that the RIP material cured with 1phr accelerator has the optimal glass transition temperature, electrical conductivity, dielectric loss and DC breakdown strength compared with RIP material cured by 0.5phr, 2phr, and 3phr accelerator. The RIP material cured with MEHHPA has better thermal and insulating properties compared with the RIP material cured with METHPA. The existence of the crepe paper amplifies the influence of accelerator and curing agent for the hydroxyl groups affect the curing process as well as the chain segment arrangement. This study provides the research support for the design of the curing formula for RIP insulation used in DC bushing. © 1994-2012 IEEE.

关键词： Dielectric losses

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