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7th IEEE International Conference on High Voltage Engineering and Application, ICHVE 2020

作者： Bin, Ding Jingwen, Liu Jianning, Chen Yuanxiang, Zhou Xuewei, Wang Jiamin, Ge Xiong'an Power Supply Company State Grid Baoding China Tsinghua University China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Beijing China Xinjiang University Department of Electrical Engineering Urumqi China

ISBN: (纸本)9781728155111

With the rapid development of ultra-high voltage (UHV) transmission technology in China, insulation diagnosis for power equipment has been applied widely to improve the reliability of the giant power system. Partial discharge (PD) detection, with the advantages of high precision and convenient deployment, plays an important role in defect detection, location, and classification. However, the low signal to noise ratio (SNR) of PD signals and poor electromagnetic environment make it difficult to extract useful features from PD signals. To distinguish the PD signals from noise, a noise reduction method based on deep learning is proposed in this paper. With short-time Fourier transform (STFT) technology, time-domain PD signals with various noise were first transformed into time-frequency domain patterns. After preprocessing the raw pattern, a deep convolutional neural network (CNN) was built, trained, and tuned for noise reduction of PD signals. Finally, the noise reduction model was verified and compared with the traditional method based on wavelet analysis. The results demonstrate that noise reduction mothed based on deep learning can restore the PD signals with more than 90% noise reduced. Given the advantage that the convolution kernel could sense both the time-related information and the frequency-related information in a spectrum simultaneously, the DnCNN model performs better than wavelet analysis. The noise reduction model proposed in this paper is based on new generation artificial intelligence, providing a new approach for PD signal restoration, which promotes the reliability of the power system. © 2020 IEEE.

关键词： Partial discharges

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Experimental study on grounding mode of secondary cable shielding layer of uhv converter station 11

Experimental study on grounding mode of secondary cable shie...

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11th Asia-Pacific International Conference on Lightning, APL 2019

作者： Zhang, Zhaohua Shi, Weidong Kang, Peng Zhang, Bo Liu, Zhuoran Shi, Lei China Electric Power Research Institute Beijing China State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Yinchuan China

ISBN: (纸本)9781728116952

Because of a lightning strike, short circuit fault, and switch operation, grounding grid will be impacted by high-frequency current, which makes the grounding grid appear uneven distribution of transient grounding potential, this kind of transient grounding potential rise will be coupled to the core wire through the outer surface of the cable and will invade the secondary system, which may have an impact on the normal operation of the secondary equipment and Endanger the safe and stable operation of substation or converter station. In addition, with the digitalization, electronization, and localization of the secondary equipment in the UHV converter station, a large number of precision secondary equipment used for protection, control and communication is placed in the high-voltage switching field of the converter station, which greatly increases the probability of interference with the secondary system of the UHV converter station. It is well known that using shielded cables and choosing correct grounding mode of the shielding layer is an important measure to improve the electromagnetic compatibility of converter stations. In this paper, based on a test method to research transient grounding potential rise in converter station, the transient overvoltage of multi-segment secondary cables and their shielding layer with different grounding modes are measured in the field of an AC filter in a UHV converter station. The test results show that the grounding of the shielding layer between the first and the last sections is the key to suppress transient overvoltage for the multi-segment control cable. The best grounding method is to increase the shielding layer and armor layer of the control cable between the on-site control cabinet to be grounded at the single end of the B-phase on-site control cabinet based on the cable grounding mode. That is to say, the cable of the shielding layer and the armor layer between the on-site control cabinet should consider the grounding at

关键词： Electric grounding

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Vibration Reduction by Segmented Continuous Variable Width Pole for Rotating Armature Permanent Magnet Motors

Vibration Reduction by Segmented Continuous Variable Width P...

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International Conference on Electrical Machines, ICEM

作者： Zhanlu Yang Shanming Wang Jianfeng Hong Chao Liu State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China Navy Submarine Academy Qingdao China

ISBN: (数字)9781728199450

ISBN: (纸本)9781728199467

In order to reduce the electromagnetic vibration of rotating armature permanent magnet motor (RAPMM), this paper proposes a method to reduce vibration using the magnetic pole with segmented continuous variable width. The distribution of flux density and radial force density in air gap is calculated using analytical method. The analytical solutions of radial exciting force and bending moment exciting force on magnetic pole are obtained. Through analysis, the principle of magnetic pole width adjustment for the reduction in radial exciting force and bending moment is developed. The magnetic field, Maxwell stress, vibration deformation and acceleration of the motor are calculated using the three-dimensional finite element method. In order to validate the effectiveness of the proposed method, a comparison is performed between the proposed scheme and the other three traditional schemes. Finally, the experimental results about the four kinds of motors are compared, to validate the proposed method.

关键词： Vibrations Permanent magnet motors Prototypes Rotors Force Stator windings Permanent magnets

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Excellent electrical properties of zinc-oxide varistors by tailoring sintering process for optimizing line-arrester configuration 7

Excellent electrical properties of zinc-oxide varistors by t...

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7th IEEE International Conference on High Voltage Engineering and Application, ICHVE 2020

作者： Meng, Pengfei Cao, Wei Chen, Chao Wan, Shuai Xu, Heng Hu, Jun He, Jinliang Tsinghua University Department of Electrical Engineering Beijing China Wuhan Nari Limited Liability Company State Grid Electric Power Research Institute Wuhan China Guangdong Aikang Electric Power Co. Ltd Guangzhou China State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Department of Electrical Engineering Beijing China

ISBN: (纸本)9781728155111

We optimized the excellent electrical performance of zinc-oxide (ZnO) varistors doping of aluminum and indium by tailoring the sintering process. The surface morphology, nonlinear volt ampere properties, capacitance-voltage characteristics, and dielectric analyses were carried out. At a given aluminum and indium concentration, the average sample grain size (d) increased as lengthening sintering time from 0.5 to 2.5 h. The voltage gradient (E_{1\{mA}}) decreased from 602.4 V/mm to 356.7 V/mm. The residual voltage of the sintered varistors at the lightning impulse current (8/20\ \mu\mathrm{s}) decreased as the samples sintering holding time extended from 0.5 to 2.0 h. When the ZnO varistor was sintered for 1.5 h, the samples showed an excellent performance, with a reference voltage of 479.3 V/mm at 1 mA DC. When assembled in the line surge arresters, the obtained high-voltage-gradient ZnO varistors can decrease their length and residual voltage, which allows for better coordination of the line surge arrester with the insulators. This study has great significance to optimize line-arrester configurations and improve power-system stability. © 2020 IEEE.

关键词： Sintering

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From distributed energy resources to virtual power plants: A cyber-physical system solution for integrating demand-side in smart grid 4

From distributed energy resources to virtual power plants: A...

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4th IEEE Conference on Energy Internet and Energy system Integration, EI2 2020

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

ISBN: (纸本)9781728196060

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. © 2020 IEEE.

关键词： Virtual power Plants

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Research on Lithium-ion Battery Safety Risk Assessment Based on Measured Information

Research on Lithium-ion Battery Safety Risk Assessment Based...

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2020 IEEE Sustainable power and Energy Conference, iSPEC 2020

作者： Zhou, Xuyan Cheng, Lin Wan, Yuxiang Qi, Ning Tian, Liting You, Feng State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China Energy Storage System Business Unite Tianjin Lishen Battery Joint-Stock Co. Ltd. Tianjin China

ISBN: (纸本)9781728191645

Lithium-ion batteries have the advantages of high energy density, fast power response, recyclability, and convenient to movement, which are unsurpassed by other energy storage systems. However, safety issues such as thermal runaway of lithium-ion batteries have become the main bottlenecks restricting the development of their extensive applications. In practical applications, the demand for battery energy storage scale and specific energy continues to increase, and the contradiction between battery high safety and battery safety has become increasingly prominent. This paper proposes a lithium-ion battery safety risk assessment method based on online information. Effective predictions are essiential to avoid irreversible damage to the battery and ensure the safe operation of the battery energy storage system before a failure occurs. This paper is expected to provide novel risk assessment method and research idea for the development and design of high-safety battery systems. © 2020 IEEE.

关键词： Lithium-ion batteries

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Life prediction and reliability analysis of motorbearing based on vibration signal 7

Life prediction and reliability analysis of motorbearing bas...

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7th International Conference on Reliability of Electrical Products and Electrical Contacts, ICREPEC 2019

作者： Xu, Helin Cheng, Lin Wan, Yuxiang Qi, Ning State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing100084 China

ISBN: (纸本)9789881532343

As an important power equipment in the power system, the electrialc motor is an important part of the transformation of electric energy and mechanical energy. Reasonable prediction of the reliability level of the running motor, timely and effectively avoid the operational risks, can effectively ensure the safety and stable operation of the power system. This paper starts with the motor vibration signal and establishes the remaining life prediction based on SVM(Support Vector Machine). Firstly, the vibration signal is denoised by wavelet transform, and the characteristic parameters such as mean square value is extracted after signal data reconstruction. Further, combined with the characteristic value, the working state is divided, and the support vector machine regression prediction model is used to obtain the remaining life of the bearing. In the case study part, data denoising and feature extraction are performed on the bearing vibration data measured by the PRONOSTIA test bench. The trend of the selected characteristic values is used for evaluating the motor operating state. The characteristic value, running state of the equipment, and remaining life which are extracted from the training set data are input to the SVM, and then the SVM is used to predict the remaining life for the test set. Finally, failure rate of the equipment can be derived. © 2019 by International Academic Publishers Ltd.

关键词： Reliability analysis

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Influences of temperature on Space Charge in Gas-to-Liquid Oil-Impregnated Paper

Influences of temperature on Space Charge in Gas-to-Liquid O...

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International Conference on High Voltage Engineering and Application, ICHVE

作者： Yuanxiang Zhou Xin Huang Ling Zhang Yunxiao Zhang Zhongliu Zhou Chenyuan Teng China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China

ISBN: (数字)9781728155111

ISBN: (纸本)9781728155128

Gas-to-liquid (GTL) transformer oil has been on trial in converter transformers. However, its influence on the space charge characteristic is not clear. This work aims at exploring space charge characteristics of GTL oil at different temperatures as well as comparing with commercial naphthenic oil (KI50X). Space charge distribution during the polarization and the dissipation process in the GTL oil-impregnated paper at different temperature was measured by the pulse electroacoustic method (PEA), which were contrasted with those of the KI50X oil-impregnated paper. Results illustrated that high temperature accelerated the injection and migration of charge carriers in the oil-impregnated paper. And the polarity of the accumulated charge in the vicinity of anode changed from positive to negative with the increase of temperature. It was perceived that oil-paper conductivity and carrier mobility grew with the increase of temperature, resulting in the easier migration of injected charge to another electrode. Furthermore, the space charge dissipation rate in the GTL oil-impregnated paper is lower than that in the naphthenic oil-impregnated paper at the same temperature. Thus, a longer time interval of tests or switch operation in the factory test and operation process may need if GTL oil is used rather than naphthenic oil.

关键词： Oils Space charge power transformer insulation Oil insulation Electric fields Distortion Temperature measurement

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Joint Multi-stage Planning of Renewable generation, HESS, and AESS for Deeply Decarbonizing power systems with High-penetration Renewables

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IEEE Transactions on Sustainable Energy 2024年

作者： Yu, Zhipeng Chi, Yingtian Lin, Jin Liu, Feng Li, Jiarong Song, Yonghua Ren, Zhengwei Lu, Chengcheng Ji, Mengbo Tsinghua University State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Beijing100087 China Tsinghua University Sichuan Energy Internet Research Institute Chengdu610213 China Harvard University Harvard John A. Paulson School of Engineering and Applied Sciences Cambridge United States University of Macau Department of Electrical and Computer Engineering Macau999078 China Tsinghua University Department of Electrical Engineering Beijing100087 China China Electric Power Planning & Engineering Institute National Electric Power Planning and Research Center Beijing100087 China Co. Ltd. Beijing100087 China Ordos City Hanxia Renewable Energy Co. Ltd. Ordos014300 China

The further decarbonization of power systems with high renewable energy penetration faces the problem of inter-day intermittence of renewable energy sources (RES) and the seasonal imbalance between RES and load demand, due to the limited regulation ability of conventional units such as thermal generation. Regular solutions based on battery energy storage system (BESS) are too costly to be practical. To address issues above, hydrogen energy storage system (HESS) and ammonia energy storage system (AESS) are introduced to gradually replace thermal generation. Specifically, first, HESS and AESS are incorporated into the multi-stage capacity expansion planning (MSCEP) model with carbon emission reduction constraints. Yearly data with hourly time resolution are utilized for each stage to accurately describe the intermittence of RES. Then, an improved column generation (CG) with Dantzig-Wolfe decomposition (DWD) embedded solution approach is used to efficiently solve the large-scale MSCEP model. Finally, a real-life system in China is studied. The results indicate that the proposed method can guarantee high power supply reliability (PSR) under different renewable energy penetration levels, avoiding the low PSR problem that may be caused by the existing typical scenario-based method (TSM) under high penetration (≥30%). Moreover, HESS and AESS are essential to reduce the cost of decarbonization. Especially under the goal of carbon neutrality, the contribution of HESS and AESS in reducing levelized cost of energy (LCOE) reaches 12.28% and 14.59%, respectively, leading to a levelized cost of carbon reduction (LCOCr) of 998 RMB/t. © 2010-2012 IEEE.

关键词： Hydrogen storage

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Communication-Efficient Federated Learning for Connected Vehicles with Constrained Resources

Communication-Efficient Federated Learning for Connected Veh...

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International Wireless Communications and Mobile Computing Conference, IWCMC

作者： Shuaiqi Shen Chong Yu Kuan Zhang Xi Chen Huimin Chen Song Ci University of Nebraska-Lincoln Omaha NE USA Beijing Electric Power Research Institute State Grid Corporation of China State Key Laboratory for Safety Control and Simulation of Power Systems and Large Power Generation Equipment Tsinghua University Beijing P. R. China

With the upcoming next generation wireless network, vehicles are expected to be empowered by artificial intelligence (AI). By connecting vehicles and cloud server via wireless communication, federated learning (FL) allows vehicles to collaboratively train deep learning models to support intelligent services, such as autonomous driving. However, the large number of vehicles and increasing size of model parameters bring challenges to FL-empowered connected vehicles. Since communication bandwidth is insufficient to upload full-precision local models from numerous vehicles, model compression is usually conducted to reduce transmitted data size. Nevertheless, conventional model compression methods may not be practical for resource-constrained vehicles due to the increasing computational overhead for FL training. The overhead for downloading global model can also be omitted by existing methods since they are originally designed for centralized learning instead of FL. In this paper, we propose a ternary quantization based model compression method on communication-efficient FL for resource-constrained connected vehicles. Specifically, we firstly propose a ternary quantization based local model training algorithm that optimizes quantization factors and parameters simultaneously. Then, we design a communication-efficient FL approach that reduces overhead for both upstream and downstream communications. Finally, simulation results validate that the proposed method demands the lowest communication and computational overheads for FL training, while maintaining desired model accuracy compared to existing model compression methods.

关键词： Training Quantization (signal) Connected vehicles Computational modeling simulation Wireless networks Collaborative work

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