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Resilience-oriented Restoration Strategy by Offshore Wind Power Considering Risk

CSEE Journal of Power and Energy systems 2023年第6期9卷 2052-2065页

作者： Junjie Rong Ming Zhou Gengyin Li the State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China

Global climate changes have created intense naturaldisasters such as typhoons, which may cause serious damage topower systems. As an emerging renewable energy resource, offshore wind power has great potential in power systems resilienceenhancement with its rapid start-up capability and developmentof anti-typhoon technology. In this paper, a restoration strategyby offshore wind power considering risk is proposed to speedup the restoration process and enhance system resilience. Specifically, a failure risk model of an individual wind turbine andthen the whole wind farm is built for predicting severe weather’simpact, with focus on failure probability. Further, a quantificationmodel of resilience enhancement and risk cost, based on customerinterruption cost assessment method, is introduced. Then, a twostage optimized decision-making model is proposed to solve thescheme of offshore wind power and conventional power unitsin load restoration process. Case studies are undertaken on amodified IEEE RTS-79 system and results indicate the proposedrestoration strategy can shorten duration of restoration andreduce customers’ economic losses meanwhile ensuring systemsafety.

关键词： Load restoration offshore wind power optimized decision-making resilience enhancement risk

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An Improved Behavioral Model for High-voltage and High-power IGBT Chips

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CSEE Journal of Power and Energy systems 2023年第1期9卷 284-292页

作者： Yixuan Yang Zhibin Zhao Cheng Peng Xuebao Li Zhiyu Sun Xiang Cui State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China

High-voltage and high-power IGBT chips have a noticeable carrier storage effect,which is related to the load ***,the research on the carrier storage effect of existing IGBT behavior models is *** this paper,An improved behavioral model for high-voltage and high-power insulated gate bipolar transistor(IGBT)chips is proposed,which could be used under different load *** problems for applying the traditional behavioral model to more load conditions are *** behavior,in the wide base region,is analyzed,and the analytical expression of the carrierstorage-effect equivalent capacitance and the initial value of the tail current are provided to establish an improved IGBT behavioral model.A corresponding parameter extraction method is *** order to verify the improved behavioral model,an experimental platform is built for resistive load and inductive load,and the results show that the accuracy of the improved behavioral model is much better than that of the traditional *** addition,the errors of the improved model are within 12.5%under different current and load *** that the maximum error of other models,which could be applied in a variety of load conditions,is more than 25%,the accuracy of the model proposed in this paper is excellent.

关键词： Carrier storage effect high voltage IGBT behavioral model turn-off transient

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Optimal biaxial prestretch ratios of soft dielectric elastomer actuators for maximal voltage-induced displacement

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Science china(Technological Sciences) 2023年第10期66卷 2871-2881页

作者： LUO Kai WU JiaNing CHEN FeiFei School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Meta Robotics Institute Shanghai Jiao Tong UniversityShanghai 200240China

Prestretch plays an indispensable role in programming the voltage-induced deformation of dielectric elastomer actuators(DEAs).However,lacking rational design methods,the level of prestretch is usually determined through time-consuming experiments and trial-and-error *** this paper,we aim to quantitatively determine the optimal biaxial prestretch ratios for maximizing the voltage-induced displacement of *** on the Lagrange method and adjoint sensitivity analysis,we obtain the derivative of the displacement field with respect to the principal prestretch ratios,in which the nonlinearities and complex electromechanical coupling of DEAs are rigorously taken into *** derivative information allows for performing gradient-based optimization at a high convergence *** propose a comprehensive optimization framework connecting the nonlinear finite element analysis and sensitivity analysis to iteratively identify the optimal prestretch *** validate our method on two classical types of DEAs,i.e.,planar DEAs with fixed boundaries and free-standing three-dimensional dielectric elastomer minimum energy structures(DEMES).The simulation and experiment results both show that remarkable improvements in concerned displacements are obtained compared with the non-optimized designs.

关键词： dielectric elastomer prestretch ratios design optimization

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Synchrophasor Measurement Method Based on Cascaded Infinite Impulse Response and Dual Finite Impulse Response Filters

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Journal of Modern Power systems and Clean Energy 2024年第5期12卷 1345-1356页

作者： Boyu Zhao Hao Liu Tianshu Bi Sudi Xu the State Key Laboratory of Alternate Electric Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China the State Grid Jiangsu Electric Power Research Institute Nanjing 210036China

High-precision synchronized measurement data with short measurement latency are required for the applications of phasor measurement units(PMUs).This paper proposes a synchrophasor measurement method based on cascaded infinite impulse response(IIR)and dual finite impulse response(FIR)filters,meeting the M-class and P-class requirements in the IEC/IEEE 60255-118-1 standard.A low-group-delay IIR filter is designed to remove out-of-band interference *** FIR filters with different center frequencies are designed to filter out the fundamental negative frequency component and obtain synchrophasor *** ratio of the amplitudes of the synchrophasor is used to calculate the frequency according to the one-to-one correspondence between the ratio of the amplitude frequency response of the FIR filters and the *** shorten the response time introduced by IIR filter,a step identification and processing method based on the rate of change of frequency(RoCoF)is proposed and *** synchrophasor is accurately compensated based on the frequency and the frequency response of the IIR and FIR filters,achieving high-precision synchrophasor and frequency estimates with short measurement *** and experiment tests demonstrate that the proposed method is superior to existing methods and can provide synchronized measurement data for M-class PMU applications with short measurement latency.

关键词： Synchrophasor measurement frequency estimation infinite impulse response filter complex bandpass filter

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Dynamic Frequency Support and DC Voltage Regulation Approach for VSC-MTDC systems

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CSEE Journal of Power and Energy systems 2023年第2期9卷 645-658页

作者： Chongru Liu Haoyu Liu Siwen Jiang Le Zheng State Key Laboratory for Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China

When an additional frequency control is implemented in the voltage source converter-based multi-terminal high voltage direct current(VSC-MTDC)system,the DC grid is capable of responding to a frequency disturbance in the AC ***,the original additional frequency control may cause the DC voltage to exceed the limit when providing power for a severe frequency disturbance,threatening the security of the DC system.A novel dynamic additional frequency control strategy for the VSC-MTDC system is developed based on the relationship between the DC voltage and the frequency droop coefficient.A dynamic frequency droop coefficient is designed to adaptively adjust the support power of the DC grid,balancing the frequency regulation of the disturbed AC system and the voltage stability of the DC grid.A DC voltage recovery method based on multi-converter cooperation is proposed to cope with the DC voltage deviation caused by the additional frequency *** validate the advantages and satisfactory performance of the proposed method during power disturbances with different severities and for the process of DC voltage recovery.

关键词： Additional frequency control DC voltage recovery module dynamic frequency droop coefficient VSCMTDC

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A novel multi-channel CNN-LSTM and transformer-based network for diesel engine misfire diagnosis under different noise conditions

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Science china(Technological Sciences) 2024年第9期67卷 2965-2967页

作者： LI Ou LEI JunBo QIN ChengJin ZHANG ZhiNan TAO JianFeng LIU ChengLiang State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Misfire fault, as a major fault of diesel engines, usually occurs because of low fuel quality, insufficient compression, ignition system failure, *** engines may experience issues such as reduced power, increased fuel consumption, and increased noise when misfire happens. Therefore, timely detection and diagnosis of diesel engine misfire faults are of great significance in the industry [1].

关键词： Diesel diagnosis network

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Effect of operational and geometric parameters on the hydrodynamics of a Wurster coater:A CFD-DEM study

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Particuology 2024年第2期85卷 62-76页

作者： Yinqiang Song Tuo Zhou Ruiqi Bai Man Zhang Hairui Yang Department of Energy and Power Engineering Tsinghua UniversityBeijing100084China Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua UniversityBeijing100084China State Key Laboratory of Power System and Generation Equipment Tsinghua UniversityBeijing100084China

A coupled CFD-DEM method was used to study the hydrodynamics of a Wurster ***,the CFD part of the model was validated by the accurate prediction of the pressure drops over a pseudo-2D fluidized bed under various gas *** effect of gas velocity,gap height,tube length and batch volume of the particles on the cycle time and the residence time of the particles was thoroughly *** central jet gas velocity ui was found to speed up the particle cycle but undermine the coating *** gas velocity at the horizontal transport zone u2 was able to promote the horizontal transport of the particles but should not be too high,otherwise,it would obstruct the normal falling back of the particles in the downward *** gap heights would decrease the coating efficiency but tube length had little impact on *** increment of batch volume would commonly abase the cycle time and the working efficiency under a given *** de-fluidization problem arose when the batch volume increased to 550 ***,this problem could be swept out by the optimization of u1 and *** a mixture of different sizes,the coarse particles enjoyed higher coating efficiency and could travel closer to the *** may shield the fine particles from getting enough coating liquids,and thus coarse particles and fine particles were not recommended to get coated in the same batch.

关键词： Numerical simulation CFD-DEM Wurster coater Hydrodynamics Cycle time Residence time

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Interface Finite Element Method with Lower Calculation Amount for Step Size-varying Electro-quasistatic Field Problem

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CSEE Journal of Power and Energy systems 2023年第5期9卷 1710-1719页

作者： Zhaocheng Liu Xiang Cui Xuebao Li Yongfan Zhan Zhibin Zhao State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China

A novel FEM called interface finite element method(I-FEM)is proposed for the step size-varying electro-quasistatic field(EQS)in this ***,the corresponding equation and interface conditions for I-FEM are ***,the numerical principle of I-FEM is *** the proposed method,by the inverse matrix modification lemma,the calculation amount of I-FEM is decreased ***,the corresponding example is given to verify the effectiveness and correctness of *** last,the error analysis and universal promotion of the proposed I-FEM are *** with the normal FEM,I-FEM can greatly decrease the calculation amount while the numerical accuracy of I-FEM is even better than the normal FEM in some case.

关键词： EQS field inverse matrix modification lemma LU decomposition

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A Unified Trajectory Optimization Approach for Long-Term and Reactive Motion Planning of Legged Locomotion

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Journal of Bionic Engineering 2023年第5期20卷 2108-2122页

作者： Yapeng Shi Bin Yu Kaixian Ba Mantian Li School of Mechanical Engineering Yanshan UniversityNo.438 West Hebei AvenueQinhuangdao066004HebeiPeople’s Republic of China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin150001People’s Republic of China

This paper proposes a unified trajectory optimization approach that simultaneously optimizes the trajectory of the center of mass and footholds for legged *** on a generic point-mass model,the approach is formulated as a nonlinear optimization problem,incorporating constraints such as robot kinematics,dynamics,ground reaction forces,obstacles,and target *** unified optimization approach can be applied to both long-term motion planning and the reactive online planning through the use of model predictive control,and it incorporates vector field guidance to converge to the long-term planned *** effectiveness of the approach is demonstrated through simulations and physical experiments,showing its ability to generate a variety of walking and jumping gaits,as well as transitions between them,and to perform reactive walking in obstructed environments.

关键词： Legged locomotion Motion planning Trajectory optimization Bionic robot

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A novel LSTM-autoencoder and enhanced transformer-based detection method for shield machine cutterhead clogging

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Science china(Technological Sciences) 2023年第2期66卷 512-527页

作者： QIN ChengJin WU RuiHong HUANG GuoQiang TAO JianFeng LIU ChengLiang State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Shield tunneling machines are paramount underground engineering equipment and play a key role in tunnel *** the shield construction process,the“mud cake”formed by the difficult-to-remove clay attached to the cutterhead severely affects the shield construction efficiency and is harmful to the healthy operation of a shield tunneling *** this study,we propose an enhanced transformer-based detection model for detecting the cutterhead clogging status of shield tunneling ***,the working state data of shield machines are selected from historical excavation data,and a long short-term memory-autoencoder neural network module is constructed to remove ***,variational mode decomposition and wavelet transform are employed to denoise the *** the preprocessing,nonoverlapping rectangular windows are used to intercept the working state data to obtain the time slices used for analysis,and several time-domain features of these periods are *** to the data imbalance in the original dataset,the k-means-synthetic minority oversampling technique algorithm is adopted to oversample the extracted time-domain features of the clogging data in the training set to balance the dataset and improve the model ***,an enhanced transformer-based neural network is constructed to extract essential implicit features and detect cutterhead clogging *** collected from actual tunnel construction projects are used to verify the proposed *** results show that the proposed model achieves accurate detection of shield machine cutterhead clogging status,with 98.85%accuracy and a 0.9786 F1 ***,the proposed model significantly outperforms the comparison models.

关键词： shield tunneling machine cutterhead clogging fault diagnosis autoencoder multihead self-attention mechanism imbalanced data

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