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IEEE PES Asia-Pacific Power and Energy engineering Conference (APPEEC)

作者： Chao Pei Zhe Zhang Xianggen Yin Xinyu Liang Yong Wang Guoyan Chen State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China Guangzhou Power Supply Bureau Co. Ltd Guangzhou China

ISBN: (纸本)9781509054190

Urban power grid is a typical load center. According to the operational characteristics and structure of urban power grid, a complete set of urban grid operation risk index system where the calculation methods of each affiliated index is given, is proposed from the point of equipment direct loss, grid structure integrity failure, grid security margin and power grid load loss. On this basis, the paper makes use of Analytic Hierarchy Process (AHP) to synthesize the affiliated index and draw the total risk index of power system to assess the risk level of power grid. Taking the Polish power grid as an example, the paper calculates and analyzes each affiliated index and the total risk index based on a preset contingency, and verifies the feasibility of the proposed risk assessment index system and methods. And the indices computed are for use by operators and operational engineers in the control room to assess system security levels as a function of existing and near-future network conditions.

关键词： Power grids Indexes Security Risk management Propagation losses Economics Power system stability

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Commutation failure analysis considering direct current dynamics in LCC-HVDC systems

Commutation failure analysis considering direct current dyna...

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12th IET International Conference on AC and DC Power Transmission (ACDC 2016)

作者： Yaping Hu Jun Lu Huafeng Zhou CSG Power Dispatching & Control Center Guangzhou 510623 China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan 430074 China

This paper presents the mechanism of LCC-HVDC system's commutation failures arising from ac faults. The theoretical analysis of commutation failure is developed by considering direct current dynamics. On the basis of the theoretical analysis, the impacts of ac fault level and fault occurring time on commutation failure are quantified. Moreover, this paper provides a more precise commutation failure criterion. Compared with the conventional, the proposed criterion reveals the relationship between commutation failure and fault occurring time and proves that commutation failure is not probabilistic events. Eventually, the analytical results are verified by the time-domain simulation based on the CIGRE BENCHMARK model in PSCAD/EMTDC.

关键词： fault occurring time commutation failure criterion direct current dynamics fault level

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On hybrid modular multilevel converters with active DC fault ride-through capability

On hybrid modular multilevel converters with active DC fault...

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12th IET International Conference on AC and DC Power Transmission (ACDC 2016)

作者： Maozeng Lu Qiang Zhou Jiabing Hu Ningbo Wang Muchao Xiang State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan 430074 China WindPower Technology Center of Gansu Electric Power Corporation Lanzhou 730050 China

This paper presents a comprehensive analysis and comparison of hybrid MMC topologies with DC fault ride-through capability (DC-FRT), consisting of half-bridge sub-modules (HBSMs) and full-bridge sub-modules (FBSMs). Overmodulation index, semiconductor count and capacitor's capacitance with a specified rated DC voltage are mainly considered. Constraints of HBSMs' capacitors voltage balancing on over-modulation index is given. Then, DC-FRT capability's requirement on the proportion of FBSMs in an arm for a given over-modulation index is deduced. Further, power increase and semiconductor count considering semiconductor's current rating are analyzed for different combinations of over-modulation index and proportion of FBSMs. Moreover, capacitances of HBSMs' and FBSMs' capacitors with the same capacitor voltage ripple are compared for different combinations of over-modulation index and proportion of FBSMs. Finally, effects of different sorting and selection algorithms on HBSMs' capacitor voltages for a specified MMC are analyzed. Simulation results using PSCAD/EMTDC are presented to verify the validity of the analysis.

关键词： power increase analysis capacitance DC fault ride-through hybrid modular multilevel converter

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Transmission level MMC DC/DC Converter for large scale integration of renewable energy into HVDC grid

Transmission level MMC DC/DC Converter for large scale integ...

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International Conference on Power Electronics and Motion Control (IPEMC)

作者： Huibin Zhang Dragan Jovcic Liangzhong Yao Wang Xiang Jinyu Wen School of Engineering University of Aberdeen Aberdeen UK China Electric Power Research Institute Beijing China Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781509012114

This paper presents the detailed description of DC/DC operation for reliable grid integration of renewable energy into HVDC grid, under normal operation and different fault conditions. The DC/DC uses the isolated dual-active-bridge DC/DC converter based on MMC (Modular Multilevel Converter) technology. Within the MMC DC/DC converter, an optimal efficiency control strategy to achieve minimal inner current magnitude and fast control for the full power range is proposed. At grid level, the 3-level cascaded current controller design achieves reliable power transfer and grid voltage control. Under normal grid operating conditions, the tie line DC/DC converter enables flexible power exchange between interconnected HVDC links. During fault conditions, the proposed DC/DC cascaded current controller limits the converter currents. The DC/DC converter will therefore function differently, either in power control mode or voltage control mode, for a proper post-fault grid management without grid-wide communication. The validity of the proposed DC/DC control is verified using a 4-terminal DC system with a large wind farm on a detailed PSCAD model for both normal and fault conditions.

关键词： Voltage control Circuit faults Limiting HVDC transmission Topology Modulation Phase locked loops

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Radiative Cooling of the Thermally Isolated System in KAGRA Gravitational Wave Telescope

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Journal of Physics: Conference Series 2021年第1期1857卷

作者： T. Akutsu M. Ando K. Arai Y. Arai S. Araki A. Araya N. Aritomi Y. Aso S.-W. Bae Y.-B. Bae L. Baiotti R. Bajpai M. A. Barton K. Cannon E. Capocasa M.-L. Chan C.-S. Chen K.-H. Chen Y.-R. Chen H.-Y. Chu Y.-K. Chu S. Eguchi Y. Enomoto R. Flaminio Y. Fujii M. Fukunaga M. Fukushima G.-G. Ge A. Hagiwara S. Haino K. Hasegawa H. Hayakawa K. Hayama Y. Himemoto Y. Hiranuma N. Hirata E. Hirose Z. Hong B.-H. Hsieh G.-Z. Huang P.-W. Huang Y.-J. Huang B. Ikenoue S. Imam K. Inayoshi Y. Inoue K. Ioka Y. Itoh K. Izumi K. Jung P. Jung T. Kajita M. Kamiizumi N. Kanda G.-W. Kang K. Kawaguchi N. Kawai T. Kawasaki C. Kim J. Kim W. Kim Y.-M. Kim N. Kimura N. Kita H. Kitazawa Y. Kojima K. Kokeyama K. Komori A. K. H. Kong K. Kotake C. Kozakai R. Kozu R. Kumar J. Kume C.-M. Kuo H.-S. Kuo S. Kuroyanagi K. Kusayanagi K. Kwak H.-K. Lee H.-W. Lee R.-K. Lee M. Leonardi C.-Y. Lin F.-L. Lin L. C.-C. Lin G.-C. Liu L.-W. Luo M. Marchio Y. Michimura N. Mio O. Miyakawa A. Miyamoto Y. Miyazaki K. Miyo S. Miyoki S. Morisaki Y. Moriwaki K. Nagano S. Nagano K. Nakamura H. Nakano M. Nakano R. Nakashima T. Narikawa R. Negishi W.-T. Ni A. Nishizawa Y. Obuchi W. Ogaki J. J. Oh S.-H. Oh M. Ohashi N. Ohishi M. Ohkawa K. Okutomi K. Oohara C.-P. Ooi S. Oshino K.-C. Pan H.-F. Pang J. Park F. E. Peiia Arellano I. Pinto N. Sago S. Saito Y. Saito K. Sakai Y. Sakai Y. Sakuno S. Sato T. Sato T. Sawada T. Sekiguchi Y. Sekiguchi S. Shibagaki R. Shimizu T. Shimoda K. Shimode H. Shinkai T. Shishido A. Shoda K. Somiya E. J. Son H. Sotani R. Sugimoto T. Suzuki H. Tagoshi H. Takahashi R. Takahashi A. Takamori S. Takano H. Takeda M. Takeda H. Tanaka K. Tanaka T. Tanaka S. Tanioka E. N. Tapia San Martin S. Telada T. Tomaru Y. Tomigami T. Tomura F. Travasso L. Trozzo T. T. L. Tsang K. Tsubono S. Tsuchida T. Tsuzuki D. Tuyenbayev N. Uchikata T. Uchiyama A. Ueda T. Uehara K. Ueno G. Ueshima F. Uraguchi T. Ushiba M. H. P. M. van Putten H. Vocca J. Wang C.-M. Wu H.-C. Wu S.-R. Wu W.-R. Xu T. Yamada K. Yamamoto T. Yamamoto K. Yokogawa J. Yokoyama T. Yokozawa T. Yoshioka H. Yuzurihar National Astronomical Observatory of Japan (NAOJ) 2-21-1 Osawa Mitaka-City Tokyo 181-8588 Japan Research Center for the Early Universe (RESCEU) The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-0033 Japan Department of Physics The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-0033 Japan Institute for Cosmic Ray Research (ICRR) The University of Tokyo 5-1-5 Kashiwa-no-Ha Kashiwa-City Chiba 277-8582Japan Accelerator Laboratory High Energy Accelerator Research Organization (KEK) 1-1 OhoTsukuba-City Ibaraki 305-0801 Japan Earthquake Research Institute The University of Tokyo 1-1-1Yayoi Bunkyo-ku Tokyo 113-0032Japan Kamioka Branch National Astronomical Observatory of Japan (NAOJ) 238 Higashi-Mozumi Kamioka-cho Hida-City Gifu Pref. Japan The Graduate University for Advanced Studies (SOKENDAI) 2-21-1 Osawa Mitaka-City Tokyo 181-8588 Japan Korea Institute of Science and Technology Information (KISTI) 245 Daehak-ro Yuseong-gu Daejeon 34141 South Korea National Institute for Mathematical Sciences 70 Yuseong-daero 1689 beon-gil Yuseong-gu Daejeon 34047 South Korea Graduate School of Science Osaka University 1-1 Machikaneyama-cho Toyonaka-City Osaka560-0043 Japan School of High Energy Accelerator Science The Graduate University for Advanced Studies (SOKENDAI) 1-1 Oho Tsukuba-City Ibaraki 305-0801 Japan Institute for Gravitational Research University of Glasgow Kelvin Building G12 8QQ UK Department of Applied Physics Fukuoka University Fukuoka Jonan Nanakuma 814-0180 Japan Department of Physics Tamkang university No.151 Yingzhuan Rd. Danshui Dist. New Taipei-City 25137 Taiwan Department of Physics the Center for High Energy and High Field Physics National Central University No. 300 Zhongda Road Zhongyi District Taiyuan-City 320 Taiwan Institute of Astronomy National Tsing Hua University No. 101 Section 2 Kuang-Fu Road Hsinchu 30013 Taiwan Department of Physics National Tsing Hua University No. 101 Section 2

Radiative cooling of the thermally isolated system is investigated in KAGRA gravitational wave telescope. KAGRA is a laser interferometer-based detector and main mirrors constituting optical cavities are cool down to 20K to reduce noises caused by the thermal fluctuation. The mirror is suspended with the multi-stage pendulum to isolate any vibration. Therefore, this mirror suspension system has few heat links to reduce vibration injection. Thus, this system is mainly cooled down with thermal radiation. In order to understand the process of radiative cooling of the mirror, we analyzed cooling curve based on mass and specific heat. As a result, it was newly found that a cryogenic part called 'cryogenic duct-shield' seems to have large contribution in the beginning of the mirror cooling. This finding will help to design new cooling system for the next generation cryogenic gravitational wave detector.

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An improved prediction control strategy of battery storage inverter

An improved prediction control strategy of battery storage i...

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International Conference on Power Electronics and Motion Control (IPEMC)

作者： Xingbao Ju Chang She Zhijian Fang Tao Cai China Ship Development and Design Center Wuhan China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technolog Wuhan China

ISBN: (纸本)9781509012114

This paper proposed an improved prediction control strategy of battery storage inverter, suppressing the large prediction error in battery storage inverter. The steady state and dynamic performance are significantly improved compared with typical prediction controller. Firstly the prediction control scheme is introduced to eliminate the influence of time consumption. Then the formation mechanism of prediction control error is obtained. The function between input voltage error and prediction error is achieved. In order to suppress the large prediction error, an improved prediction control strategy is proposed in this paper, which uses the integral of back ward difference. At last, the proposed control strategy is realized in a 30kW prototype. And the steady state error is reduced from 9% to 1%.

关键词： Batteries Inverters Predictive models Voltage control Steady-state Control systems Load modeling

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Equivalent electromagnetic Model of Self-blocking MMC with DC fault isolation capability

Equivalent Electromagnetic Model of Self-blocking MMC with D...

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IEEE Power and Energy Society General Meeting

作者： Wang Xiang Weixing Lin Jinyu Wen Liangzhong Yao Zhibing Wang State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China Renewable Energy Department China Electric Power Research Institute Beijing China

ISBN: (纸本)9781509041695

Self-blocking MMC (SB MMC) is able to isolate DC fault current and is promising for use in overhead HVDC transmission. Each converter arm of a SB MMC is consisted of half the self-blocking sub-module (SBSM) and half the half bridge (HB) sub-module. This hybrid design achieves the DC fault isolation capability without significantly increase of the cost and power loss. The detailed electro-magnetic simulation of SB MMC with hundreds of voltage levels is time consuming. Since a SBSM can be negatively inserted, the dynamics of SB MMC are different from HB MMC under DC fault condition. The conventional equivalent models of HB MMC are not sufficient for SB MMC. To solve the above challenges, an equivalent electromagnetic model for SB MMC is proposed and verified in this paper.

关键词： Capacitors Insulated gate bipolar transistors Switches Voltage control Topology Circuit faults Biological system modeling

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Lightning performance of EHV and UHV overhead transmission Lines in China southern power grid

Lightning performance of EHV and UHV overhead transmission L...

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International Conference on Lightning Protection (ICLP)

作者： Hansheng Cai Lei Jia Gang Liu Shangmao Hu Jian Shi Hengxin He Xiangen Zhao Junjia He China Southern Power Grid Electric Power Research Institute Guangzhou China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781509048434

Lightning stroke is the main cause of trip-outs of EHV and UHV transmission lines in China Southern Power Grid (CSG). In order to improving the lightning performance of overhead transmission lines, the lightning activities of CSG in 2006 to 2014 was analyzed. It indicates that the coastal Guangdong and Guangxi province are suffered more ground flashes, where the average ground flash density is over 7.98 flashes/km 2 /year. 306 lightning flashover incidents of 500kV AC, ± 500kV HVDC and ± 800kV UHVDC transmission lines were investigated. It is inferred that about 84% lightning flashover incidents was caused by lightning shielding failure. The corresponding ground wire protection angle for 81% incidents is larger than 5°, and with protection angle decreases, lightning trip-out failures are significantly reduced. Based on the guidelines proposed by IEEE and CIGRE working group, CSG has developed their own lightning risk estimation tool named LPTL. The predication result of six 500kV AC transmission lines was compared to field experience which validates the IEEE recommended method for 500kV AC transmission lines. Further works should be done to revisit the validity of existing risk estimation method for HVDC transmission lines.

关键词： Estimation Lightning protection Power transmission lines Power grids Flashover Decision support systems

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Transient over-voltage of the full-bridge MMC HVDC system with overhead line fault

Transient over-voltage of the full-bridge MMC HVDC system wi...

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International Conference on High Voltage engineering and Application, ICHVE

作者： Shuyi Dong Hengxin He Zhao Yuan Ying Yang Junjia He Huiwen He State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China High Voltage Technology Research Division China Electric Power Research Institute Wuhan China

ISBN: (纸本)9781509004973

The widely used Line Commutated Converter (LCC) suffers from commutation failure which might cause severe economic and secure consequence. The recently proposed Modular Multilevel Converter (MMC) HVDC is expected to be an alternative solution. However, the half bridge MMC (HBMMC) cannot interrupt the short current caused by DC transmission line fault, which have stunted the engineering practice of MMC in the long-distance overhead transmission line situation. A hybrid LCC-FBMCC system was proposed in this paper. Firstly, based on the parameter of a practical ±500kV HVDC project, the electromagnetic simulation model of this LCC-FBMCC system was established in PSCAD/EMTDC. Secondly, the electromagnetic transient process under DC line fault was simulated. The transient over-voltage characteristics of the LCC-FBMMC system were compared with that of the LCC-HBMMC system. Finally, the DC fault ride ability and the impact of DC short fault on the power transmission was discussed, which can present reference to the development and application of MMC in remote and bulk power transmission area.

关键词： HVDC transmission Power transmission lines Voltage control Fault currents Topology Bridge circuits

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The research of suppressing motor noise and vibration based on negative magnetostrictive effect

The research of suppressing motor noise and vibration based ...

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IEEE Conference on electromagnetic Field Computation

作者： Xin Zhang Lianhe Li Yuehua Geng Qingxin Yang Chaoqun Xie Lihua Zhu Tianjin Polytechnic University Key Laboratory of Advanced Electrical Engineering and Energy Technology Tianjin China Hebei University of Technology Province-Ministry Joint key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability Tianjin China

ISBN: (纸本)9781509010332

Noise suppression is one of the key issues to be solved in the design and application of the motor. Especially in larger motors, noise and vibration caused by the magnetostrictive effect of silicon steel accounted for a large proportion of the motor noise. This paper focuses on how to solve the problem of motor noise and vibration suppression caused by the magnetostrictive effect of silicon steel, and proposes a method that filling a soft magnetic composite materials that have negative magnetostrictive properties to suppress motor noise and vibration based on the filling material magnetic permeability and the resistivity of silicon being consistent with the silicon steel. The negative magnetostrictive deformation offset the positive magnetostrictive deformation so as to achieve the purpose of noise reduction. Create electromagnetic-mechanical coupling numerical model to calculate negative magnetostriction filler. Calculate the size and position of a reasonable distribution of the motor structure. This method is verified by Numerical Calculations.

关键词： Magnetostriction Soft magnetic materials Magnetic hysteresis Silicon Magnetic domains

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