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An improved optimal control strategy for hybrid AC/DC power system

IOP Conference Series: Earth and Environmental Science 2018年第1期188卷

作者： C H Gao W M Liu T T Zheng Z W Liu S H Miao Y L Kang Z H Fan Y L Liu M M Zhang State Grid East Inner Mongolia Electric Power Company Limited Electric Power Research Institute Hohhot 010020 China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Hubei Electric Power Security and High Efficiency Key Laboratory School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan 430074 China

The additional modulation function of high voltage direct current (HVDC) links can improve the system stability while the unavoidable random external disturbance and sudden changes seriously affect the controller performance and the system stability. In this paper, an improved control scheme based on inverse optimal adaptive control is proposed for the hybrid AC/DC system which considers the system parameter error, external disturbance and other random perturbation. The proposed control scheme combines the inverse optimal control approach and the adaptive control method to account for the modelling errors and uncertainty, which aims at the disturbance attenuation and the optimal operating of the hybrid AC/DC power system. Besides, the improved PI (Proportional-Integral) controller based on the lead-lag link for the current control of HVDC system is proposed to further improve system dynamic performance. Simulations conducted on a typical hybrid AC/DC system show the correctness and validity of the proposed control method.

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Coordinated control strategy of doubly fed wind power generation system under unbalanced grid voltage

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IOP Conference Series: Earth and Environmental Science 2018年第1期188卷

作者： C H Gao Y L Kang S H Miao Z W Liu Z H Fan Y L Liu W M Liu T T Zheng M M Zhang State Grid East Inner Mongolia Electric Power Company Limited Electric Power Research Institute Hohhot 010020 China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Hubei Electric Power Security and High Efficiency Key Laboratory School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan 430074 China

A coordinated control method for doubly fed wind power generation system under unbalanced grid voltage is presented in this paper, which can remove the negative effects of unbalanced voltage on the doubly fed induction generator (DFIG) such as the unbalance of stator and rotor current. And the method can suppress the double frequency oscillations of the output active and reactive power. To improve the operating performance, the operation mechanism of DFIG system with a series grid side converter (SGSC) under unbalanced grid voltage is described firstly, and the strategy for series grid side converter aiming at maintaining the stator three phase voltage balance is proposed, and then the stator and rotor currents will keep balanced. Meanwhile, the mathematical model of the parallel grid side converter (PGSC) is analysed under unbalanced grid voltage and the double frequency power control equation is established. According to the control equation, a control strategy based on a proportional resonance (PR) power compensator for the parallel grid side converter is put forward, then the control goal of suppressing the double frequency oscillations of the output active and reactive power of the whole system simultaneously is accomplished, which improves the output quality of the system and ensures the safe operation of the connected grid. The proposed coordinated control strategy in this paper verified by the simulations of a doubly fed wind power generation system model built in PSCAD/EMTDC.

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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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2016 IEEE Power and Energy Society General Meeting, PESGM 2016

作者： Xiang, Wang Lin, Weixing Wen, Jinyu Yao, Liangzhong 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)9781509041688

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. © 2016 IEEE.

关键词： HVDC power transmission

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Optimal protection coordination based on dual directional over-current relays for ring network distribution power systems 8th

Optimal protection coordination based on dual directional ov...

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8th Asia-Pacific Power and Energy engineering Conference, APPEEC 2016

作者： Wang, X.Y. Wang, X.G. Chen, D.H. Su, S. Lin, X.N. China Electric Power Research Institute Haidian District Beijing China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology WuhanHubei Province China

ISBN: (纸本)9781138028463

In terms of Distributed Generation (DG), it is momentous to ensure a fast and reliable protection system for the looped network to avoid involuntary DG disconnection during fault conditions. In this paper, dual setting directional over-current relays are put forward to protect meshed distribution systems with DG. Compared to the conventional approach, which is using a directional relay of onesetting, the new protection coordination scheme counts on the dual setting relays. Dual setting relays are equipped with two inverse time-current characteristics whose settings will depend on the fault direction. The protection coordination problem for the dual setting directional relay is elaborated as a nonlinear programming problem where the objective is to minimize the overall time of operation of relays during primary and backup operation. The proposed scheme is applied to the power distribution network, which is equipped with synchronous and inverter-based DG. The results show that the new protection coordination scheme with the dual setting relay can considerably reduce the overall relay operating time, making it an attractive option for distribution systems with DG. © 2016 Taylor & Francis Group, London.

关键词： Inverse problems

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Numerical study on propagation mechanism and bio-medicine applications of plasma jet

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High Voltage 2016年第2期1卷 62-73页

作者： He Cheng Xin Liu Xinpei Lu Dawei Liu State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and TechnologyWuHanHuBeiPeople’s Republic of China IFSA Collaborative Innovation Center Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong UniversityXi’anPeople’s Republic of China

In this study,the propagation mechanism of plasma jet and some bio-medical applications are investigated by two-dimensional numerical *** key equations of plasma physics and chemistry related with plasma jet are firstly *** simulation results suggest that the sheath forms near the dielectric tube inner surface,which results in the plasma channel to shrink in the radial direction inside the dielectric *** photoionisation of air species plays a crucial role in the transition from the localised discharge to *** Penning ionisation increases the electric conductivity of the plasma channel and facilitates the formation of ring-shaped plasma *** the plasma jet in the open air,electronimpact dissociation of H2O,electron neutralisation of H2O+,as well as dissociation of H2O by O(1D)are found to be the main reactions to produce *** micro plasma jet,the higher ignition voltage as the tube diameter decreased is attributed to the deceasing pre-avalanche electron density inside the *** simulation of plasma treatment of bacteria biofilm indicates that the mean free path of charged species inμm scale permitted the plasma penetrate into the cavity of the biofilm,and the structure of the biofilm results in the non-uniform distribution of ROS and *** simulation of plasma treatment of cells immersed in liquid suggests that the HO2 generated by plasma aqueous species is the only way for superoxide to penetrate cell membrane and damage cytosolic fumarase B.

关键词： propagation mechanism dielectric

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The research and the development of the wide area relaying protection based on fault element identification

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Protection and Control of Modern Power Systems 2016年第1期1卷 95-107页

作者： Xianggen Yin Zhe Zhang Zhenxing Li Xuanwei Qi Wenbin Cao Qian Guo State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and TechnologyWuhan 430074China

The urgent problem of the relaying protection in the modern AC/DC hybrid connected grid and the development of the wide area communication,the information process and the intelligent technology powerfully promotes the development of the technology of the wide area relaying protection(WARP),which has become a research hotspot that attracts extensive *** from the basic concept of the wide area relaying protection,this paper analyses the advantages,the effects and the functions of the wide area relaying *** two main approaches to realize the wide area protection,which are on-line adaptive setting(OAS)principle and fault element identification(FEI),are introduced in this *** at improving the performance of the backup protection,the research content and the technology demand of the wide area protection are proposed,meanwhile,the basic principle and the algorithm of the fault element identification are *** last,the scheme of the limited wide area relaying protection based on the existing pilot channel of the main protection is discussed.

关键词： Wide area protection Wide area relaying protection On-line adaptive setting Fault element identification The limited wide area protection

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Magnetically controlled saturable reactor core vibration under practical working conditions 17

Magnetically controlled saturable reactor core vibration und...

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17th Biennial IEEE Conference on electromagnetic Field Computation, IEEE CEFC 2016

作者： Tong, Ben Qingxin, Yang Rongge, Yan Lihua, Zhu Province-Ministry Joint Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability Hebei University of Technology Tianjin China Municipal Key Laboratory of Advanced Technology of Electrical Engineering and Energy Tianjin Polytechnic University Tianjin China

ISBN: (纸本)9781509010325

Magnetically controlled saturable reactors (MCSRs) are widely used in high voltage power system, but they make larger vibration and noise than transformers and other types of reactors due to the gapped iron-core structure and magnetic saturation. The main reasons of MCSR vibration are magnetostrictive effect of silicon steel sheet and electromagnetic force between core discs. This paper studies the influence of these two kinds of forces on MCSR vibration, which will be used to help seek new vibration reduction method. Firstly, because MCSRs work in DC bias conditions, multigroup magnetic and magnetostrictive characteristics of silicon steel sheet considering anisotropy under different DC bias excitation conditions are tested. Secondly, based on energy variation principle and virtual work principle, an electro-magneto-mechanical coupled numerical model for MCSRs is established. In order to compare the influence of magnetostrictive effect with electromagnetic force effect on MCSR vibration, vibration accelerations caused by magnetostrictive effect, electromagnetic force and the combination of them are calculated, respectively. From the computation results, it can be seen that the total acceleration is not simple superposition of electromagnetic acceleration with magnetostrictive acceleration. Finally, vibrations of a MCSR under different practical working conditions are tested to prove the validity of the proposed model. © 2016 IEEE.

关键词： Vibration analysis

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Impacts of PLL on the DFIG-based WTG’s Electromechanical Response Under Transient Conditions:Analysis and Modeling

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CSEE Journal of Power and Energy Systems 2016年第2期2卷 30-39页

作者： Dongliang Zhang Yajing Wang Jiabing Hu Shicong Ma Qing He Qiang Guo State Key Laboratory of Advanced Electromagnetic Engineering and Technology and Huazhong University of Science and TechnologyWuhan 430074China Ningbo Electric Power Design Institute Co.Ltd. Ningbo 315000China China Electric Power Research Institute Beijing 100192China

Increased penetration of wind energy in the electric grid has necessitated studying the impact of wind integration on the transient stability of the power system,with urgency to develop appropriate electromechanical models of the wind turbine generator(WTG).The representation and control of the WTG’s electric signals are typically in a rotational dq coordinate system whose reference angle is provided by a phase-lockedloop(PLL).The PLL is commonly considered as a measurement device and is often absent in existing WTG electromechanical *** paper studies the impact of PLL on the DFIG-based WTG electromechanical response by theoretical and simulation *** dynamics of the PLL are found to greatly influence the WTG electromechanical response,suggesting that PLL should be regarded as an indispensable control loop rather than a measurement device,and its impact should be modeled when establishing the WTG electromechanical model.

关键词： DFIG-based WTG electromechanical model phase-locked-loop(PLL) transient stability

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Search for continuous gravitational waves from 20 accreting millisecond x-ray pulsars in O3 LIGO data

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Physical Review D 2022年第2期105卷 022002-022002页

作者： R. Abbott T. D. Abbott F. Acernese K. Ackley C. Adams N. Adhikari R. X. Adhikari V. B. Adya C. Affeldt D. Agarwal M. Agathos K. Agatsuma N. Aggarwal O. D. Aguiar L. Aiello A. Ain T. Akutsu S. Albanesi A. Allocca P. A. Altin A. Amato C. Anand S. Anand A. Ananyeva S. B. Anderson W. G. Anderson M. Ando T. Andrade N. Andres T. Andrić S. V. Angelova S. Ansoldi J. M. Antelis S. Antier S. Appert Koji Arai Koya Arai Y. Arai S. Araki A. Araya M. C. Araya J. S. Areeda M. Arène N. Aritomi N. Arnaud S. M. Aronson K. G. Arun H. Asada Y. Asali G. Ashton Y. Aso M. Assiduo S. M. Aston P. Astone F. Aubin C. Austin S. Babak F. Badaracco M. K. M. Bader C. Badger S. Bae Y. Bae A. M. Baer S. Bagnasco Y. Bai L. Baiotti J. Baird R. Bajpai M. Ball G. Ballardin S. W. Ballmer A. Balsamo G. Baltus S. Banagiri D. Bankar J. C. Barayoga C. Barbieri B. C. Barish D. Barker P. Barneo F. Barone B. Barr L. Barsotti M. Barsuglia D. Barta J. Bartlett M. A. Barton I. Bartos R. Bassiri A. Basti M. Bawaj J. C. Bayley A. C. Baylor M. Bazzan B. Bécsy V. M. Bedakihale M. Bejger I. Belahcene V. Benedetto D. Beniwal T. F. Bennett J. D. Bentley M. BenYaala F. Bergamin B. K. Berger S. Bernuzzi D. Bersanetti A. Bertolini J. Betzwieser D. Beveridge R. Bhandare U. Bhardwaj D. Bhattacharjee S. Bhaumik I. A. Bilenko G. Billingsley S. Bini R. Birney O. Birnholtz S. Biscans M. Bischi S. Biscoveanu A. Bisht B. Biswas M. Bitossi M.-A. Bizouard J. K. Blackburn C. D. Blair D. G. Blair R. M. Blair F. Bobba N. Bode M. Boer G. Bogaert M. Boldrini L. D. Bonavena F. Bondu E. Bonilla R. Bonnand P. Booker B. A. Boom R. Bork V. Boschi N. Bose S. Bose V. Bossilkov V. Boudart Y. Bouffanais A. Bozzi C. Bradaschia P. R. Brady A. Bramley A. Branch M. Branchesi J. E. Brau M. Breschi T. Briant J. H. Briggs A. Brillet M. Brinkmann P. Brockill A. F. Brooks J. Brooks D. D. Brown S. Brunett G. Bruno R. Bruntz J. Bryant T. Bulik H. J. Bulten A. Buonanno R. Buscicchio D. Buskulic C. Buy R. L. Byer L. Cadonati G. Cagnoli C. Cahillane J. Calderón Bustillo J. D. Callaghan T. A. Callister E. Ca LIGO Laboratory California Institute of Technology Pasadena California 91125 USA Louisiana State University Baton Rouge Louisiana 70803 USA Dipartimento di Farmacia Università di Salerno I-84084 Fisciano Salerno Italy INFN Sezione di Napoli Complesso Universitario di Monte S. Angelo I-80126 Napoli Italy OzGrav School of Physics & Astronomy Monash University Clayton 3800 Victoria Australia LIGO Livingston Observatory Livingston Louisiana 70754 USA University of Wisconsin-Milwaukee Milwaukee Wisconsin 53201 USA OzGrav Australian National University Canberra Australian Capital Territory 0200 Australia Max Planck Institute for Gravitational Physics (Albert Einstein Institute) D-30167 Hannover Germany Leibniz Universität Hannover D-30167 Hannover Germany Inter-University Centre for Astronomy and Astrophysics Pune 411007 India University of Cambridge Cambridge CB2 1TN United Kingdom Theoretisch-Physikalisches Institut Friedrich-Schiller-Universität Jena D-07743 Jena Germany University of Birmingham Birmingham B15 2TT United Kingdom Center for Interdisciplinary Exploration & Research in Astrophysics (CIERA) Northwestern University Evanston Illinois 60208 USA Instituto Nacional de Pesquisas Espaciais 12227-010 São José dos Campos São Paulo Brazil Gravity Exploration Institute Cardiff University Cardiff CF24 3AA United Kingdom INFN Sezione di Pisa I-56127 Pisa Italy Gravitational Wave Science Project National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan Advanced Technology Center National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan INFN Sezione di Torino I-10125 Torino Italy Università di Napoli “Federico II” Complesso Universitario di Monte S. Angelo I-80126 Napoli Italy Université de Lyon Université Claude Bernard Lyon 1 CNRS Institut Lumière Matière F-69622 Villeurbanne France Department of Physics The University of Tokyo Bunkyo-ku Tokyo 113-0033 Japan Research Center for the Early Un

Results are presented of searches for continuous gravitational waves from 20 accreting millisecond x-ray pulsars with accurately measured spin frequencies and orbital parameters, using data from the third observing run of the advanced LIGO and advanced Virgo detectors. The search algorithm uses a hidden Markov model, where the transition probabilities allow the frequency to wander according to an unbiased random walk, while the J-statistic maximum-likelihood matched filter tracks the binary orbital phase. Three narrow subbands are searched for each target, centered on harmonics of the measured spin frequency. The search yields 16 candidates, consistent with a false alarm probability of 30% per subband and target searched. These candidates, along with one candidate from an additional target-of-opportunity search done for SAX J1808.4−3658, which was in outburst during one month of the observing run, cannot be confidently associated with a known noise source. Additional follow-up does not provide convincing evidence that any are a true astrophysical signal. When all candidates are assumed nonastrophysical, upper limits are set on the maximum wave strain detectable at 95% confidence, h095%. The strictest constraint is h095%=4.7×10−26 from IGR J17062−6143. Constraints on the detectable wave strain from each target lead to constraints on neutron star ellipticity and r-mode amplitude, the strictest of which are ε95%=3.1×10−7 and α95%=1.8×10−5 respectively. This analysis is the most comprehensive and sensitive search of continuous gravitational waves from accreting millisecond x-ray pulsars to date.

关键词： Gravitational waves Binary stars Neutron stars & pulsars

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DC–DC autotransformer with un-interrupted operating capability during DC fault

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The Journal of engineering 2017年第13期2017卷 1280-1284页

作者： Mengbo Li Wang Xiang Wenping Zuo Liangzhong Yao Weixing Lin Jinyu Wen State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Hubei Province People's Republic of China Renewable Energy Department China Electric Power Research Institute Beijing 100192 People's Republic of China TBEA China Xinjiang Sunoasis Co. Ltd Xinjiang Province People's Republic of China

This study proposed a novel type of DC/DC converter, termed as un-interrupted DC autotransformer (DC AUTO), which has capability to ride through various kinds of DC fault without blocking any devices. Firstly, the working principles and the corresponding design procedures of the un-interrupted DC AUTO are illustrated. Then an effective control strategy is proposed to enable steady operation during both normal time and faulted condition. Finally, a 1000 MW ± 320 kV/ ± 640 kV test system is built on PSCAD/EMTDC platform to testify the technical feasibility of the proposed converter and the effectiveness of the proposed control strategy.

关键词： HVDC power convertors DC-DC power convertors autotransformers HVDC power transmission DC–DC autotransformer un-interrupted operating capability DC fault DC/DC converter un-interrupted DC autotransformer DC AUTO faulted condition power 1000.0 MW voltage 640.0 kV

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