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2021 IEEE Sustainable power and Energy Conference, iSPEC 2021

作者： Cui, Liu Peng, Guangqiang He, Jingsong Wu, Jiyang Mao, Chizu Jiao, Ning Electric Power Research Institute China Southern Power Grid State Key Laboratory of Hvdc GuangZhou China Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System GuangZhou China Csg Key Laboratory for Power System Simulation Electric Power Research Institute China Southern Power Grid GuangZhou China Maintenance Test Center Ehv Power Transmission Company Guangzhou China Csg Key Laboratory for Dc Transmission Equipment State Evaluation and Fault Diagnosis GuangZhou China Sichuan University College of Electrical Engineering and Information Technology Chengdu China

ISBN: (纸本)9781665414395

Modular multilevel converter (MMC) is currently the most concerned voltage source converter topology in the field of flexible direct current transmission (VSC-HVDC). Due to its non-linear characteristics, harmonic components will inevitably be generated in AC and DC systems, which may affect the operation of equipment and system, cause protection equipment to malfunction, and cause interference to neighboring communications. The MMC converter is a non-linear device, which can be considered as an amplifying modulator with voltage and current conversion functions. The AC and DC networks are coupled to each other through the MMC converter to generate dynamic harmonic interaction. In recent years, harmonic instability problems have appeared in many VSC-HVDC projects. Compared with other converter topologies, the transfer relationship of harmonics on the AC and DC sides of MMC converters has not been studied in depth. In this paper, by studying the AC/DC harmonic conversion characteristics of MMC converters, it reveals the conversion law of MMC converters between AC/DC harmonics;through theoretical derivation, the quantitative calculation method of MMC harmonic transmission process is given. PSCAD simulation results prove the correctness of the above results. © 2021 IEEE.

关键词： Transmissions

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Research on surface electric field of parallel gap

Research on surface electric field of parallel gap

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2011 7th Asia-Pacific International Conference on Lightning, APL2011

作者： Yu, Junjie Yu, Zhanqing Zeng, Rong Chen, He Peng, Xiang State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Beijing 100084 China Maintenance and Test Center of EHV Power Transmission Company China Southern Power Grid Co. Ltd. Guangzhou 510663 China

ISBN: (纸本)9781457714665

With parallel gap, by controlling the motion path of the electric arc, effectively avoid burning and damaging the insulator during lightning strike so that the effect to reduce the accident rate of line is obvious. Because of simple structure, convenient installation and good economical efficiency, its importance in measures of lightning protection for transmitting line is continually improved. Electric field characteristics on the surface of parallel gap electrode have obvious influence on corona generation and the gap breakdown position and are the key parameters that must be considered in the design. Based on the finite element method, this paper sets up the analysis model of electric field of parallel gap including the tower, the conductor and the insulator, uses ANSOFT software for simulation, studies the surface electric field characteristics of parallel gap electrode, compares the electric field of four types of parallel gap put forward in the paper and analyzes the law of influence of parallel gap electrode parameters on the electric field characteristics. The results show that, when the short circuit distance is increased, the maximum values of electric field of ball end and snap ring body are obviously increased;the opening angle of snap ring is larger and the maximum value of electric field of ball end is higher;when the pipe diameter is increased, the maximum value of electric field of snap ring body is reduced considerably;the ball end is bigger and the maximum value of electric field of ball end is less;the ring pipe diameter is the structure parameter having the largest influence on the surface electric field;for the ball end at the end of ring electrode, the structure parameter having the largest influence on the electric field is the diameter of ball end. Reducing the distance that the ball end stands out of the ring plane can decrease the maximum value of electric field of ball end. © 2011 IEEE.

关键词： Finite element method

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Analysis of Excitation Characteristics of Ultra High Frequency Electromagnetic Waves Induced by PD in GIS

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高电压技术 2013年第8期39卷 1893-1901页

作者： DING Dengwei GAO Wensheng YAO Senjing LIU Weidong HE Jiaxi Sichuan Electric Power Research Institute Chengdu 610072 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China Shenzhen Power Supply Co. Ltd Shenzhen 518001 China

The understanding of the excitation mechanism of ultra high frequency (UHF) electromagnetic waves (EW) is essential for ap- plying UHF method to partial discharge (PD) detection. Since the EW induced by PD in gas insulated switchgear (GIS) contains not only transverse electromagnetic (TEM) wave, but also high-order transverse electric (TE) and high-order transverse magnetic (TM) waves, we analyzed the proportions between the TEM wave and the high order waves, as well as the influence of the PD position on this proportion, using the finite different time domain (FDTD) method. According to the unique characteristics of the waves, they are separated only ap- proximately. It is found that the high-order mode is the main component, more than 70%, of the electric field around the enclosure of GIS, and that with the increasing distance between PD source and inner conductors, the low frequency ( below about 800 MHz) component of EW decreases, but the high frequency component (above 1 GHz) increases, meanwhile the proportion of high-order components in EW could reach 77% from 70%. It concluded that the closer the PD source to the enclosure is, the easier high order EW may be excited.

关键词：超高频电磁波励磁特性 GIS PD 诱导气体绝缘开关设备 UHF方法 TEM波

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Research on impulse discharge characteristics of parallel gap

Research on impulse discharge characteristics of parallel ga...

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2011 7th Asia-Pacific International Conference on Lightning, APL2011

作者： Chen, He Peng, Xiang Yu, Zhanqing Yu, Junjie Zeng, Rong Maintenance and Test Center of EHV Power Transmission Company China Southern Power Grid Co. Ltd. Guangzhou 510663 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)9781457714665

With parallel gap, by controlling the motion path of the electric arc, effectively avoid burning and damaging the insulator during lightning strike so that its importance in measures of lightning protection for transmitting line is continually improved. Initial discharge position is key consideration during design of parallel gap and depends on discharge characteristics of parallel gap under the action of lightning surge when the lightning strikes the tower or line. This paper gives three types of parallel gap used to protect the composite insulator, sets up the impulse discharge test and observation platform including high-speed camera, studies the impulse discharge characteristics of parallel gap and analyzes the influence of structural parameters on the discharge characteristics. This study showed that there is randomness for discharge path of parallel gap;three types of parallel gap given in this paper can achieve 100% discharge rate of parallel gap;the determinant of discharge rate in the presupposition discharge area (PDA) is the distance that the presupposition discharge area stands out of the whole electrode plane. When this distance exceeds 20mm or more, it can ensure that most of the discharge occurs in the PDA;the parallel gap can reduce the insulation distance of 4000mm insulator about 40mm, U50 about 1%, which may approximately consider that the parallel gap has no influence on the insulating property of the insulator. © 2011 IEEE.

关键词： Electric arcs

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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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Optimal allocation of distributed generators in a distribution network using adaptive multi-objective particle swarm optimization

Optimal allocation of distributed generators in a distributi...

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2011 International Conference on Electrical, Information Engineering and Mechatronics, EIEM 2011

作者： Cheng, Shan Chen, Min-You Fleming, Peter J. Li, Xia State Key Laboratory of Power Transmission Equipment and System Security and New Technology School of Electrical Engineering Chongqing University Chongqing China Department of Automatic Control and Systems Engineering University of Sheffield Sheffield United Kingdom

ISBN: (纸本)9781447124665

This study presents the optimal allocation of distributed generators (DGs) in distribution network based on an adaptive multi-objective particle swarm optimization (AMPSO). In order to enable the DGs to make the best contribution to the distribution network, a multi-objective optimization model addressing power loss and a voltage stability index (VSI) is constructed, in which the capacity factor of DGs is taken into consideration. In the AMPSO, some adaptive techniques including the use of dynamically changing inertia weight, time-varying acceleration coefficients, mutation operation and circular crowding sorting have been integrated to improve the convergence and the diversity performance of the algorithm. The proposed algorithm has been used to determine the optimal allocation of DGs in a IEEE 33-bus distribution network. simulation results show that the proposed method can identify the optimal solutions with a good tradeoff between the power loss and the VSI. © 2012 Springer-Verlag London Limited.

关键词： Multiobjective optimization

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Multi-source information based current matching state estimation for distribution network

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Dianli Xitong Zidonghua/Automation of Electric power systems 2012年第16期36卷 53-57页

作者： Ju, Yuntao Wu, Wenchuan Cheng, Xueqi Zhang, Boming Sun, Hongbin State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing 100084 China Weifang Power Supply Bureau Shandong Provincial Power Corporation Weifang 261000 China

By taking into account the real-time measurement with low redundancy and of only partial current in distribution systems and referring to the quasi-real-time current measuring data of the metering system, the current matching technique is proposed to solve the distribution network state estimation. The matching current equations in the sense of optimal estimation and its systematic solution are deduced. Based on the assumption that the load power factor is stable, a quasi-real-time measurement generating method is proposed for loads. With boundaries demarcated by real-time current measurement, the distributed network is divided into several measured areas and current matching state estimation is made for each area. Numerical tests and results of an actual system show that the method proposed can satisfy the real-time application demand of the distribution system. ©2012 state Grid Electric power Research Institute Press.

关键词： state estimation

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Development of a frequency dependent network equivalent based RTDS-TSA hybrid transient simulation platform with heterogeneous architecture

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Dianli Xitong Zidonghua/Automation of Electric power systems 2014年第16期38卷 88-93页

作者： Hu, Yizhong Wu, Wenchuan Zhang, Boming Department of Electrical Engineering Tsinghua University Beijing100084 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing100084 China

For the simulation of large-scale AC/DC hybrid systems, both the precision of the DC parts and the efficiency of the whole system should be considered. Thus a real-time hybrid transient simulation platform is proposed by combining the real-time digital simulator (RTDS) and a transient stability analysis (TSA) program. A latest GTFPGA card is used to realize the high speed digital communication between RTDS and the computer deploying TSA program. Moreover, the frequency dependent network equivalent (FDNE) is implemented in this simulation platform to improve the accuracy of simulation results. By simulating a modified New England 39-bus test system incorporating high-voltage direct current (HVDC) components, the validity of the proposed simulation platform is verified.

关键词： Transient analysis

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power transformer condition assessment by on-line monitoring and trend analysis

Power transformer condition assessment by on-line monitoring...

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IASTED International Conference on power and Energy systems and Applications, PESA 2012

作者： Xie, Qijia Gao, Shengyou Zhang, Hailong Dai, Wen Ruan, Ling Nie, Dexin Lu, Wenhua Key Laboratory of High-Voltage Field-Test Technique of SGCC Hubei Electric Power Testing and Research Institute Wuhan China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China State Grid Electric Power Research Institute Wuhan China School of Electrical Engineering Wuhan University Wuhan China

power transformer condition assessment is the basi of condition-based maintenance and plays a very important role in carrying assets management and risk assessment for power system. As the heart of transmission and transformation system, power transformer's condition has close relation with many factors, such as the production quality of itself, operation environment and so on. This paper analyzes some variables which could represent the transformer's condition, including the data from preventative test, factory test and commission test, diagnostic test, on-line detection and monitoring, routine inspection, operation history, family defection and environment information. Some parameters which have representation are chosen as the condition variables. Artificial neuron network (ANN) and Dempster-Shafer (D-S) evidence theory are adopted to form the multiparameter information fusion condition assessment model. Besides the static value, the change trends of some parameters are considered as an independent evidence section. Cooperating with on-line monitoring, it will be helpful to improve the accuracy and efficiency of condition assessment.

关键词： power transformers

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Real-time charging optimization method considering vehicle charging prediction

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Dianli Xitong Zidonghua/Automation of Electric power systems 2014年第9期38卷 61-68页

作者： Li, Zhengshuo Guo, Qinglai Sun, Hongbin Xin, Shujun Department of Electrical Engineering Tsinghua University Beijing100084 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing100084 China

With large-scale electric vehicles (EVs) integrated into the power system, how to optimize EV charging power in real time to avoid incremental peak load and achieve valley-filling will be important. The regular real-time charging optimization as well as the vehicle charging prediction method is reviewed at first. Since vehicle charging (especially vehicle fleet charging) is predictable, a new real-time charging optimization model is proposed on the basis of the regular method with the consideration of the prediction model of incoming EVs. The new model is solved with receding horizon optimization, obtaining the current optimized charging power of plugged EVs. Through case study with various prediction accuracies, it can be seen that the proposed method always approaches the optimal solution to valley-filling. Moreover, compared with regular method, the proposed method would make a greater improvement of optimization result in the case of more diverse EV plug-in time. ©2014 state Grid Electric power Research Institute Press.

关键词： Forecasting

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