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arXiv 2023年

作者： Yu, Zhipeng Lin, Jin Liu, Feng Li, Jiarong Zhao, Yuxuan Song, Yonghua The State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100087 China Sichuan Energy Internet Reasearch Institute Tsinghua University Chengdu610213 China The Department of Electrical and Computer Engineering University of Macau 999078 China The Department of Electrical Engineering Tsinghua University Beijing100087 China

Isolated renewable power to ammonia (IRePtA) has been recognized as a promising way to decarbonize the chemical industry. Optimal sizing of the renewable power system is significant to improve the techno-economic of IRePtA since the investment of power sources exceeds 80% of the total investment. However, multi-timescale electricity, hydrogen, and ammonia storages, minimum power supply for system safety, and the multiyear uncertainty of renewable generation lead to difficulties in planning. To address the issues above, an IGDT-MILFP model is proposed. First, the levelized cost of ammonia (LCOA) is directly formulated as the objective, rendering a mixed integer linear fractional programming (MILFP) problem. Information gap decision theory (IGDT) is utilized to handle the multiyear uncertainty of renewable generation. Second, a combined Charnes-Cooper (C&C) transformation and Branch-and-Bound (B&B) method is proposed to efficiently solve the large-scale IGDT-MILFP model, giving robust and opportunistic planning results. Then, Markov Chain Monte Carlo (MCMC) sampling-based posteriori analysis is leveraged to quantify the long-run performance. Finally, a real-life system in Inner Mongolia, China, is studied. The results indicate that the proposed methods could reduce the computational burden by orders of magnitude for solving a large-scale MILFP problem. Moreover, the proposed IGDT-MILFP model is necessary and accurate to obtain an optimal capacity allocation with the lowest expected LCOA (3610 RMB/t) in long-run simulations. Copyright © 2023, The Authors. All rights reserved.

关键词： Ammonia

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基于广域低功耗网络的能源物联网

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Engineering 2017年第4期 67-82页

作者：宋永华林今唐明董树锋 State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University College of Electrical Engineering Zhejiang University Center of Internet of Energy Things Tsinghua-Sichuan Energy Internet Institution

为了应对严峻的环境压力以及化石能源的枯竭危机,能源行业正在世界范围内共同推进能源互联网这一新型能源系统,目标以智能电网为骨架,综合电、气、热等多种能源形式,大幅提升能源系统对可再生能源的消纳能力。能源的需求侧是能源互联网... 详细信息

为了应对严峻的环境压力以及化石能源的枯竭危机,能源行业正在世界范围内共同推进能源互联网这一新型能源系统,目标以智能电网为骨架,综合电、气、热等多种能源形式,大幅提升能源系统对可再生能源的消纳能力。能源的需求侧是能源互联网的发展重点,也是新能源消纳灵活性的全新来源,具有巨大的技术发展潜力与市场空间。然而现有的能源信息技术并不能完全适应能源需求侧的运行特点,难以被高效经济地应用于能源互联网的需求侧管控之中,已成为当前能源需求侧技术发展的瓶颈。为了突破这一技术难点,本文提出利用通信领域近年来高速发展的广域低功耗网络(low power wide area network,LPWAN)技术,构造全新的能源物联网,从而为能源互联网需求侧的发展带来了全新的技术突破。LPWAN是一类具有远距离、低功耗、海量接入、低运维成本的通信技术的总称,与Wi-Fi、蓝牙、紫蜂(ZigBee)等局域物联网技术相比真正实现了大区域的低成本覆盖。本文介绍以窄带物联网(narrow band internet of things,NB-IoT)和运程(long range,LoRa)为代表的LPWAN技术,提出基于该技术实现的能源物联网体系架构。最后,本文展望了能源物联网技术驱动下,能源互联网需求侧的典型应用场景。

关键词：能源物联网广域低功耗网络 NB-IoT LoRa 需求侧

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Crack Growth Prediction of the Steam Turbine Generator Shaft

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Journal of Physics: Conference Series 2011年第1期305卷

作者： Dongxiang Jiang Chao Liu State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Thermal Engineering Tsinghua University Beijing 100084 People's Republic of China

The power network in China is encountering great changes and large-scale network is increasingly implemented for long distance power transmission as well as various kinds of power electronic devices, which bring in the risk of the torsional vibration of the turbine generator shafts, may cause the fatigue damage and cracks in the product life cycle. The paper analyzed the failed coupling of some 600MW steam turbine generator and calculated the local stress of the assembly under torsional load caused by the network disturbance. Then the crack propagation was analyzed with the predicted crack initiation position and crack propagation routine. The assembled coupling contains shaft, coupling and keys with interferences between the parts. Therefore the contact analysis was included. Extended Finite Element Method (X-FEM) is used to calculate the crack propagation and that the mesh needs not to be regenerated with the crack propagation, which is beneficial for engineering applications.

关键词：

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Adaptive Sliding Mode control of Flexible Load Driven by Motors considering the damping

Adaptive Sliding Mode Control of Flexible Load Driven by Mot...

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International Conference on Electrical Machines and systems

作者： Youshuang Ding Xi Xiao State Key Lab of Security Control and Simulation of Power Systems and Large Scale Generation Equipment Department of Electrical Engineering Tsinghua University China

ISBN: (纸本)9781467388634

This paper presents an adaptive sliding mode controller for the system of flexible load driven by motors with the damping and friction considered. The controller comprised the sliding mode controller and the Kalman estimator. Firstly, the parameter uncertainties and disturbance are modeled with a bounded variable and then an integral sliding surface is designed. Then, to relax the requirement for the bound of uncertainties, a Kalman state estimator is proposed to estimate the bound of uncertainties and the unmeasurable states. With the proposed control structure, the vibration caused by the flexibility can be suppressed and besides, the controller is robust to a wide range of parameter uncertainty and disturbance. The performance of the control strategy is verified via simulation and experimental results.

关键词： Flexible joint flexible manipulator sliding mode adaptive Kalman filter

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Analysis and Design for Hydrogen-Fueled Cascade Solid Oxide Fuel Cell System

SSRN

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SSRN 2023年

作者： Liu, Peiyuan Zhang, Yongliang Zhu, Jianzhong Han, Minfang Sun, Kaihua Zhong, Haijun Zhang, XueRui State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Energy and Power Engineering Tsinghua University Beijing100084 China Xuzhou Huatsing Jingkun Energy Co. Ltd. Jiangsu Province 221005 China Petrochemical Research Institute China National Petroleum Corporation Beijing112206 China Institute of Process Engineering Chinese Academy of Sciences Beijing100190 China

Maximizing total fuel utilization is the key to improving the electrical efficiency of solid oxide fuel cell (SOFC) systems. The cascade system can achieve this effectively, but there are fewer studies on hydrogen-fueled cascade systems, and the determination of suitable rated power ratios needs a basis. Because of the characteristics of cascade systems, a fast model that can predict performance at low flow rates and low hydrogen partial pressures is required. Using multiple sets of experimental data, this study developed and validated an improved semi-empirical model, which accurately predicted the industrial-sized cell performance at different flow rates and hydrogen partial pressures. On this basis, the basic parallel and cascade system models were established. The effects of fuel flow rate, rated power ratio, split ratio, and constraints on the system performance were studied and analyzed, and the appropriate design and operation parameters of the cascade system were determined. The results indicated that the cascade system can significantly improve electrical efficiency compared to the parallel system by selecting suitable design parameters. In the example of a 10-kW rated power system design, the cascade system improved the electrical efficiency by over 9% at rated power compared to the parallel system. The results obtained provide valuable reference for related research and offer guidance for system design. © 2023, The Authors. All rights reserved.

关键词： Electrical efficiency

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Impedance fault location algorithm for UHV long transmission lines with single-line-to-ground faults

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Dianli Xitong Zidonghua/Automation of Electric power systems 2008年第14期32卷 25-29页

作者： Wang, Bin Dong, Xinzhou Bo, Zhiqian Klimek, Andrew State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China AREVA T and D Automation Co. Stafford ST17 4LX United Kingdom

Ultra-high-voltage (UHV) transmission lines (over 750 kV) normally have larger shunt capacitance and longer transmission radius, which impose limitations of direct application of traditional impedance algorithm. A novel impedance fault location algorithm is proposed for UHV transmission lines with single-line-to-ground faults due to higher voltage level than 750 kV. It is based on the precondition that the negative sequence current phase at meter location can precisely describe the phase information of negative current in fault path or fault voltage. The algorithm is immune to the influence of shunt capacitance with distributed parameters modeling for transmission line, and is not disturbed by fault resistance with fault location calculation at zero-crossing point of voltage at fault point. Theoretical analysis and simulation prove that the proposed method can guarantee good fault location accuracy, and fulfill the requirements in the field.

关键词： Electric lines

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Improved Blade Tip Timing in Blade Vibration Monitoring with Torsional Vibration of the Rotor

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Journal of Physics: Conference Series 2012年第1期364卷

作者： Chao Liu Dongxiang Jiang State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Thermal Engineering Tsinghua University Beijing 100084 People's Republic of China

Due to the complex conditions in rotating machinery, the blades usually encounter fluctuating loads, and failures may occur in the operation. Blade vibration is rarely monitored in the practical rotating machinery in power plants as the traditional blade vibration method using strain gauge method is hard to be applied in long-time and online monitoring. The blade tip timing method is a promising approach to monitor the blade vibration and several special sensors are developed to realize the online monitoring. Based on the traditional blade tip timing method, an improved approach is established in this work. The proposed method can modify the expected arriving time when the torsional vibration exists. The accuracy is therefore improved in the torsional vibration case. Then the blade vibration monitoring with the traditional blade tip timing method and the proposed method are carried out in the test rig in laboratory. The results validate that, the torsional vibration influences the expected arriving time, and the proposed method can modify the expected arriving time and improve the accuracy of the blade vibration monitoring.

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Functionality identification for the testing systems with large-scale highly-concentrated wind power integration by long-distance transmission lines

Functionality identification for the testing systems with la...

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IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT Europe)

作者： Jiabing Hu Yunhe Hou Feng Liu Yongning Chi Shuanglei Feng Haiyan Tang Guobing Song Xiaoming Yuan State Key Lab of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China Department of Electrical and Electronic Engineerig The University of Hong Kong Hong Kong China State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China China Electric Power Research Institute Beijinz China Department of Electrical Engineering Xi’ an Jiaotong University Xi'an China

ISBN: (纸本)9781479977215

Large-scale, highly-concentrated wind power integrated into grids through long transmission lines will bring significant challenges to power system operation during steady-state and dynamic processes. Tremendous research has been conducted in this critical area. However, few, if any available testing systems have been established to meet the requirements of the research on different time-scales. The objective of this paper is to identify the functionality requirements of the testing systems for the comprehensive studies, which covers different time-scale problems of power systems. For this purpose, the realistic Gansu power grids in China and wind farms in Jiuquan area are selected. As a typical power grid with large-scale highly-concentrated wind power integration by long-distance transmissions, the characteristics of the selected wind farms and power grid are discussed first. Two simplified systems are constructed associated with the major characteristics. The critical functionality requirements of the testing systems for different research purposes, i.e., system planning, operation, control, and protection, are identified. As the first step, this paper scopes the key requirements and, ultimately, a complete testing system is expected.

关键词： Wind power generation power system stability Stability analysis Testing Wind farms Frequency control power grids

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Chance-Constrained Generic Energy Storage Operations under Decision-Dependent Uncertainty

arXiv

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arXiv 2022年

作者： Qi, Ning Pinson, Pierre Almassalkhi, Mads R. Cheng, Lin Zhuang, Yingrui State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China The Dyson School of Design Engineering Imperial College London LondonSW7 2AZ United Kingdom The Department of Electrical and Biomedical Engineering University of Vermont BurlingtonVT05405 United States

Compared with large-scale physical batteries, aggregated and coordinated generic energy storage (GES) resources provide low-cost, but uncertain, flexibility for power grid operations. While GES can be characterized by different types of uncertainty, the literature mostly focuses on decision-independent uncertainties (DIUs), such as exogenous stochastic disturbances caused by weather conditions. Instead, this manuscript focuses on newly-introduced decision-dependent uncertainties (DDUs) and considers an optimal GES dispatch that accounts for uncertain available state-of-charge (SoC) bounds that are affected by incentive signals and discomfort levels. To incorporate DDUs, we present a novel chance-constrained optimization (CCO) approach for the day-ahead economic dispatch of GES units. Two tractable methods are presented to solve the proposed CCO problem with DDUs: (i) a robust reformulation for general but incomplete distributions of DDUs, and (ii) an iterative algorithm for specific and known distributions of DDUs. Furthermore, reliability indices are introduced to verify the applicability of the proposed approach with respect to the reliability of the response of GES units. simulation-based analysis shows that the proposed methods yield conservative, but credible, GES dispatch strategies and reduced penalty cost by incorporating DDUs in the constraints and leveraging data-driven parameter identification. This results in improved availability and performance of coordinated GES units. © 2022, CC BY.

关键词： Energy storage

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Physical Passivation of Deep-Level Defect states in Polymer Dielectrics for Outstanding Dielectric Properties

SSRN

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SSRN 2023年

作者： Li, Xiao-Fen Wang, Tian-Yu Yin, Si-Jia Zhang, Gui-Xin Liu, Jian-Bo Liu, Bai-Xin School of Materials Science and Engineering Tsinghua University Beijing100084 China State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China College of Art and Design Visual Communication Design SuZhou University Suzhou234111 China

The limited dielectric strength of polymer dielectrics hampers their reliable use in highly integrated electrical systems and high-energy storage film capacitors. This constraint is closely associated with the presence of deep-level defect states in polymer dielectrics. Here, we present an efficient and stable approach for the physical passivation of deep-level defect states aimed at enhancing the dielectric properties of polymer dielectrics. Employing inductively coupled plasma technology with argon as the carrier gas, the polymer undergoes substantial decreased deep-level defect states, as evidenced by nano-micro-region defect measurements. Consequently, the localized charge accumulation in the treated polymer dielectric is significantly reduced, resulting in a remarkable 62% increase in flashover voltage. The breakdown strength is also enhanced, and the treated material exhibits long-term stability. Moreover, materials featuring passivated deep-level defect states can boost discharge energy density without compromising efficiency. For instance, PTFE with passivated deep-level defect states maintains a discharge energy density of 1.18 J/cm3 and a charge-discharge efficiency of 95.06% at 200 °C and 300 MV/m. By focusing on deep-level defect states passivation, we introduce a strategy for receiving polymers with exceptional performance and stability. © 2023, The Authors. All rights reserved.

关键词： Passivation

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