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Lightning protection study of transmission line, Part II: Analysis methods

Gaodianya Jishu/High Voltage Engineering 2009年第12期35卷 2910-2916页

作者： Zeng, Rong He, Jin-Liang Chen, Shui-Ming State Key Lab. of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

Design is the key of lightning protection of transmission lines, and lightning protection analysis is the base to estimate the lightning protection behaviors of transmission line and the effect of lightning protection measures for transmission line. We mainly discussed the development states and the existed problems in lightning protection analysis of transmission line in the world, presented the analysis methods on the lightning backflash and shielding failure of transmission line and their comprehensive applications, and proposed the suitable models and methods for lightning protection analysis of transmission line. The whole-wave- progress analysis model should be applied to calculate the lightning transient characteristics of transmission line when the lightning strikes the tower or the overhead ground wires of transmission line;different analysis methods, such as electrogeometric method, the leader propagating model and the fractal model, should be used to calculate the shielding failure behaviors of transmission line. The lightning protection analysis of transmission lines should consider the micro-typological characteristics and the area difference of lightning parameters along transmission line, and comprehensively estimate the lightning protection behaviors of transmission line sections.

关键词： Electric lines

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Lightning protection study of transmission line, Part I: Lightning parameters

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Gaodianya Jishu/High Voltage Engineering 2009年第12期35卷 2903-2909页

作者： Chen, Shui-Ming He, Jin-Liang Zeng, Rong State Key Lab. of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

Obtaining actual lightning parameters is the fundament of lightning protection of transmission lines. Based on the comprehensive analysis on the methods to acquire lightning parameters, we analyzed the current research states and existed problems of lightning parameters, including annual lightning day, ground flash density, magnitude and waveform of lightning current. The lightning activities have obvious topographical feature, presently the lightning location system (LLS) should be fully applied to acquire the annual lightning day, ground flash density, magnitude of lightning current in different areas. Moreover, the monitoring devices of lightning current should be installed on typical transmission towers with different voltage grades in different areas to obtain the characteristics of real lightning current waveforms and magnitudes, and calibrate and check the lightning current magnitudes obtained from LLS. All these would make the lightning protection of power system focusing on the actual targets. Four sets of the developed monitoring devices of lightning current were installed, and the first lightning current waveform in China, which was similar to the standard waveform recommended by CIGRE, was recorded.

关键词： Electric lines

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Aerodynamic Optimization of a Simplified SUV Model

Aerodynamic Optimization of a Simplified SUV Model

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International Conference on Digital Manufacturing and Automation (ICDMA)

作者： Jing-yu Wang Chang-hai Yang Xing-jun Hu Bo Guo Key Lab. of Manuf. & Test Tech. for Automobile Parts of Minist. of Educ. Chongqing University of Technology Chongqing Chongqing CN State Key Lab. of Automotive Simulation & Control Jilin University Changchun Jilin CN Lab. of Ultra-Precision Fabrication Changchun Inst. of Equip. & Process Changchun China

The aerodynamics characteristics of square Mira model were researched by simulation and wind tunnel test. The velocity distribution, pressure distribution, drag coefficient and the aerodynamic characteristics around model were achieved. With contras the results of simulation and wind tunnel test, it validated the veracity of simulation. Based on results, the back spoiler was added and the fixing angle was changed. The drag coefficient was achieved. The conclusions provide reference for how to reduce drag coefficient of SUV.

关键词： Manufacturing Automation

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Lightning protection study of transmission line, Part III: Protection measures

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Gaodianya Jishu/High Voltage Engineering 2009年第12期35卷 2917-2923页

作者： He, Jin-Liang Zeng, Rong Chen, Shui-Ming State Key Lab. of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

The lightning accidents threaten the safe operation of power system. We comprehensively analyzed the developing states, the existed problems in analysis methods and measures of transmission line lightning protection, and discussed the key issues of transmission line lightning protection in China that should be studied. The lightning protection measures are divided into back-up type and leading-type methods, so-called back-up type method is used in lightning protection of transmission line in China, which complicates lightning protection;but the so-called leading-type method is used in other countries, which simplifies lightning protection. The lightning protection measures for different sections of transmission lines should be comprehensively estimated and proposed by considering the micro-topographical feature and the regional performances of lightning parameters along transmission line. The lightning protection should be fully considered in transmission line design, reducing shielding angle of overhead wire, decreasing grounding resistances of tower footings, and suitably installing line surge arresters are fundamental methods of lightning protection of new transmission line.

关键词： Electric lines

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Consensus-based Nodal Pricing Mechanism for Automated Demand Response Considering Congestion Management on Distribution Networks

Consensus-based Nodal Pricing Mechanism for Automated Demand...

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IEEE/IAS Industrial and Commercial Power System Asia (I&CPS Asia)

作者： Gang Luo Yijing Chen Yue Zhao Yujun He Chao Gong Chen Zhao Power Dispatching and Control Center Guangdong Power Grid Co. Ltd Guangzhou China Electric Power Research Institute China Southern Power Grid Co. Ltd Guangzhou China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China

ISBN: (数字)9781728143033

ISBN: (纸本)9781728143040

This paper investigates a consensus-based nodal pricing mechanism for incenting automated demand response in the deregulated market environment. These small-scale customers are autonomously managed by automated demand response (DR) controllers, which are capable of scheduling user's load devices to follow a day-ahead 24h price signal from electricity distribution companies (EDC). First, an alternating current optimal power flow (ACOPF) on the distribution network is formulated considering the participation of automated DR. Then, a consensusbased approach is exploited to adjust the nodal price and DR profile for each customer using primal-dual decomposition. The proposed mechanism is compared with a day-ahead pricing (DAP) program on a test distribution network and numerical results have shown promising performance in supporting the congestion management on the distribution grid.

关键词： Pricing Load management Load modeling Power grids Mathematical model Dispatching Companies

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Efficient Inactivation of Uv Resistant Bacteria (Urb) by Combined Uv and Chlorine Disinfection

SSRN

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SSRN 2024年

作者： Cao, Ke-Fan Chen, Zhuo Wei, En-Jing Huang, Bang-Hao Gao, Yu-Jia Wu, Yin-Hu Hu, Hong-Ying Environmental Simulation and Pollution Control State Key Joint Laboratory Key Laboratory of Microorganism Application and Risk Control of the Ministry of Ecology and Environment School of Environment Tsinghua University Beijing100084 China Beijing Laboratory for Environmental Frontier Technologies Beijing100084 China Beijing Key Lab for Source Control Technology of Water Pollution College of Environmental Science and Engineering Beijing Forestry University Beijing100083 China Tsinghua Jiangsu Suzhou215163 China

Ultraviolet (UV) is widely used for wastewater and reclaimed water disinfection due to its high efficiency. However, some bacteria exhibit strong resistance to UV disinfection (referred to as UV resistant bacteria, or URB), which can survive after disinfection and pose various risks. In this study, two bacterial strains with strong UV resistance (Deinococcus soli and Sphingomonas panni) were isolated from reclaimed water. Neither single UV disinfection nor single chlorine disinfection can effectively inactivate these URB strains. To effectively control URB, the combined disinfection of UV and chlorine was investigated, and the results showed a significant improvement in inactivation efficiency with synergistic effects. Further analysis using total antioxidant capacity tests, qPCR detection, and SYTO9/PI staining techniques revealed that the main mechanism behind the synergistic effects was the enhanced damage to intracellular content and DNA. Finally, through cost analysis and disinfection tests with actual reclaimed water, the performance of the combined disinfection method was comprehensively evaluated. The results demonstrate combined disinfection has lower costs, higher inactivation rates, and less selectivity. This study can provide a reliable method for controlling the risks caused by URB in water. © 2024, The Authors. All rights reserved.

关键词： Cost benefit analysis

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Reliability Assessment of Generation and Transmission Systems Considering Multi-Form Access of "Source-Network-Load-Storage"

Reliability Assessment of Generation and Transmission System...

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Sustainable Power and Energy Conference (iSPEC)

作者： Ning Qi Lin Cheng Yi Jiang Jinshan Luo Ke Sun Dan Wang Liang Cheng Quanquan Wang State Key Lab. of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China State Grid Economic and Technological Research Institute Co. Ltd. Beijing China State Grid Jiangsu Electric Power Co. LTD. State Grid Jiangsu Economic Research Institute Jiangsu China

ISBN: (纸本)9781728149318

Reliability assessment is the key to ensure the security of power system, however, the rapid development of “source-network-load-storage” cause enormous obstacle to the traditional reliability method. A improved method for reliability assessment of generation and transmission systems is proposed in this paper which lays importance on the coordinate operation and uncertainty of “source-network-load-storage”. Firstly, the reliability and operation model of “source-network-load-storage” is proposed to handle certain novel elements. Then the reliability assessment with operation simulation is proposed to make balance between generation and load under uncertainty. Finally, numerical analysis focusing on the different form and proportion of “source-network-load-storage” is tested in IEEE RTS-79 system so as to demonstrate the practicality and effectiveness of the improved method.

关键词： reliability assessment renewable energy energy storage operation simulation generation and transmission system reliability evaluation energy storage Renewable energy Generation and Transmission Transmission systems Power system security

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ANALYSIS OF FATIGUE LIFE LOSS OF DRIVETRAIN OF DOUBLY-FED WIND TURBINES UNDER SHORT-CIRCUIT FAULT OF POWER GRID

ANALYSIS OF FATIGUE LIFE LOSS OF DRIVETRAIN OF DOUBLY-FED WI...

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International Conference on Renewable Power Generation

作者： Qiu Shilong Li Hui Gong Lijiao Wang Bin Chai Zhaoseng Wu You Department of Mechanical and Electrical Engineering Shihezi University Shihezi China State Key Laboratory of Power Drivetrain Equipment and System Security Chongqing University Chongqing China State Key Lab of Control and Simulation of Power Systems and Generation Equipments (Department of Electrical Engineering) Tsinghua University Haidian District Beijing China State Key Laboratory of Power Drivetrain Equipment and System Security Chongqing University Chongqing China

ISBN: (数字)9781839531248

ISBN: (纸本)9781839531255

The shafting drivetrain of the doubly fed wind turbine is the part with the highest failure rate. The electromagnetic torque fluctuation caused by the grid fault easily results in the torsional vibration fatigue loss of the shaft. Accordingly, the influences of drivetrain fatigue life loss under different grid faults require investigation. Firstly, the four-mass model of the drivetrain is constructed on the basis of MATlab/Simulink. Secondly, the electromagnetic torque response under short-circuit fault of the grid is obtained via model simulation. Finally, the effects of different types of grid faults on the fatigue life of the drivetrain are analysed through Mlife. Results show that the electromagnetic torque fluctuation load generated by grid fault has no apparent influence on the fatigue life of the drivetrain in the short term, but the cumulative effect of short-term damage will aggravate the fatigue life loss of the drivetrain and increase the failure risk of the component. The electromagnetic torque generated by the three-phase symmetrical short-circuit is the most violent and has the maximum effect on the fatigue life of the drivetrain.

关键词： WIND TURBINE SHORT-CIRCUIT FAULT TORSIONAL VIBRATION FATIGUE LIFE DRIVETRAIN

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Risk-based study on under voltage load shedding schemes

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2006年第19期26卷 18-22页

作者： Dai, Jian-Feng Zhu, Ling-Zhi Zhou, Shuang-Xi Lu, Zong-Xiang State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Beijing 100084 China

A risk based method is proposed to design under voltage load shedding (UVLS) scheme. Different with traditional methods, the proposed one employs a series of risk indices, which are obtained based on a full-scale contingencies analysis, to determine the operating parameters of load shedding. According to this method, the load bus, in which the UVLS can exert itself with the highest efficiency to prevent voltage collapse, is selected as the first candidate to execute load shedding. And the amount of loads to be shed is identified though a relationship between risk values and shedding amount. The selection of shedding time conforms to the principle that the compound risk brought by failed shedding and unexpected shedding must be the minimum. Experiments conducted for IEEE 39-bus system reveal that the proposed method redound to identify the location, amount and time of load shedding more accurately and reasonably due to taking into account a great deal of uncertain factors.

关键词： Electric load shedding

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Study on probability of voltage instability based on the stochastic characteristic of load margin index

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2006年第13期26卷 26-30页

作者： Dai, Jian-Feng Wang, Hai-Chao Zhou, Shuang-Xi Lu, Zong-Xiang Zhu, Ling-Zhi State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Beijing 100084 China

In order to make up the deficiency of traditional analytical method used in the research of voltage stability problem, we need to know the probability information concerned with voltage instability. Therefore, this paper proposes a method to calculate the probability of voltage instability based on the stochastic characteristic of load margin index. This method firstly determines the stochastic characteristic of load margin index through an analysis about the randomicity of parameters which tie up with the tracing of critical point in continue power flow computation, and then figures out the probability of voltage instability by using moment and cumulate method. Owing to take into account more uncertain factors' influence on the voltage stability, the result acquired by this method is much more accurate and reasonable. A numerical simulation based on IEEE 39-bus system reveals that the proposed method works properly.

关键词： Electric power systems

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