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Analysis on carbon emission reduction intensity of fuel cell vehicles from a life-cycle perspective

Frontiers in Energy 2024年第1期18卷 16-27页

作者： Ziyuan TENG Chao TAN Peiyuan LIU Minfang HAN Fuel Cell and Energy Storage Center Department of Energy and Power EngineeringState Key Laboratory of Control and Simulation of Power Systems and Generation EquipmentTsinghua UniversityBeijing 100084China

The hydrogen fuel cell vehicle is rapidly developing in China for carbon reduction and *** paper evaluated the life-cycle cost and carbon emission of hydrogen energy via lots of field surveys,including hydrogen production and packing in chlor-alkali plants,transport by tube trailers,storage and refueling in hydrogen refueling stations(HRSs),and application for use in two different *** also conducted a comparative study for battery electric vehicles(BEVs)and internal combustion engine vehicles(ICEVs).The result indicates that hydrogen fuel cell vehicle(FCV)has the best environmental performance but the highest energy ***,a sufficient hydrogen supply can significantly reduce the carbon intensity and FCV energy cost of the current *** carbon emission for FCV application has the potential to decrease by 73.1%in City A and 43.8%in City *** only takes 11.0%–20.1%of the BEV emission and 8.2%–9.8%of the ICEV *** cost of FCV driving can be reduced by 39.1%in City *** improvement can be obtained with an economical and“greener”hydrogen production pathway.

关键词： hydrogen energy life-cycle assessment(LCA) fuel cell vehicle carbon emission energy cost

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Flexible region aggregation of adjustable loads via an adaptive convex hull strategy

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Global Energy Interconnection 2025年第1期8卷 106-120页

作者： Yisha Lin Zongxiang Lu Ying Qiao Ruijie Chen State Key Lab of Power Systems Operation and Control (Department of Electrical Engineering Tsinghua University)BeijingPR China State Grid Quanzhou Electric Power Supply Company QuanzhouPR China

Increasing interest has been directed toward the potential of heterogeneous flexible loads to mitigate the challenges associated with the increasing variability and uncertainty of renewable *** the aggregated flexible region of load clusters managed by load aggregators is the crucial basis of power system scheduling for the system *** is because the aggregation result affects the qual-ity of the scheduling schemes.A stringent computation based on the Minkowski sum is NP-hard,whereas existing approximation meth-ods that use a special type of polytope exhibit limited adaptability when aggregating heterogeneous *** study proposes a stringent internal approximation method based on the convex hull of multiple layers of maximum volume boxes and embeds it into a day-ahead scheduling optimization *** numerical results indicate that the aggregation accuracy can be improved compared with methods based on one type of special polytope,including boxes,zonotopes,and ***,the reliability and economy of the power sys-tem scheduling can be enhanced.

关键词： Aggregation Flexible region Heterogeneous load power system scheduling

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Creating and Studying a Methodology for Calculating a Resistive Voltage Divider for Use in Electronic Voltage Transformers 7

Creating and Studying a Methodology for Calculating a Resist...

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7th International Scientific and Technical Conference Relay Protection and Automation, RPA 2024

作者： Yablokov, A.A. Panashchatenko, A.V. Gotovkina, E.E. Maltsev, R.A. Ivanovo State Power Engineering University Electric Power Systems Automatic Control Department Electric Systems Department Ivanovo Russia

ISBN: (纸本)9798331501105

In 2017 the Russian government approved a programme, Russian Federation Digital Economy, the main goal of which is to create an ecosystem with large scale use of digital format data in all fields of social and economic activity [1]. The electric power industry is being transformed in accordance with the concept, Digital Transformation 2030, developed by Russian power Grids PLC [2]. Pursuant to this concept, electric substations under construction should be digital. At present, Russia has a number of operating digital substations (DSS) (Medvedevskaya SS, UVAT SS, Desna SS, Tobol SS [3]-[5], while many DSSs are at the design or construction stage. The creation of new substations, and also reconstruction of already operating ones, requires solving the problems of operating conventional electromagnetic current and voltage transformers. Electromagnetic voltage transformers (VT) are energy-inefficient, explosion - and flammability- hazardous equipment (due to their requiring additional charging with low consumption by micro-processing devices), with large weight and dimensions (an NKF-100 type transformer weighing 840 kg). © 2024 IEEE.

关键词： Distribution transformers

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Electrical tree degradation of MgO/epoxy resin composites at different voltage frequencies

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High Voltage 2024年第3期9卷 581-590页

作者： Yunxiao Zhang Wenxin Lin Yuanxiang Zhou Weiwei Xing Jiayu Cheng Chenyuan Teng College of Electrical Engineering and Automation Fuzhou UniversityFujian Key Laboratory of New Energy Generation and Power ConversionFuzhouChina State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical EngineeringTsinghua UniversityBeijingChina

Electrical tree degradation is one of the main causes of insulation failure in high-frequency *** tree degradation is studied on pure epoxy resin(EP)and MgO/EP composites at frequencies ranging from 50 Hz to 130 *** results show that the tree initiation voltage of EP decreases,while the growth rate and the expansion coefficient increase with ***,the bubble phenomenon at high frequencies in EP composites is *** with trap distribution character-istics within the material,the intrinsic mechanism of epoxy composites to inhibit the growth of the electrical tree at different frequencies is *** can be concluded that more deep traps and blocking effect are introduced by doping nano-MgO into EP bulks,which can improve the electrical tree resistance performance of EP composites in a wide frequency range.

关键词： composites tree Electrical

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Assessment of the Digital Measuring Transformers Application in power Distribution Zone

Assessment of the Digital Measuring Transformers Application...

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2024 International Russian Automation Conference, RusAutoCon 2024

作者： Filatova, Galina Lebedev, Vladimir Tolstoukhov, Andrey Ivanovo State Power Engineering University Automatic control of electric power systems department Ivanovo Russia

Combined digital measuring current and voltage transformers (DCVTs), developed at Ivanovo State power engineering University (ISPEU), are innovative products. The researchers have accumulated some operating experience of devices in existing electrical installations and experience in numerous laboratory tests. At the same time, a number of aspects of the DCVT use still remain the subject of research, for example, the functioning of DCVTs as a primary sensor for protection against single-phase ground faults (SPGFs). It is also necessary to evaluate the effect of the introduction of DCVTs in the overhead networks of power distribution zones (PDZs), primarily from the point of view of reducing the costs of searching for the location of the SPGFs. The procedure for searching for an electrical fault using the functions built into DCVT 6 -10 kV is described. The article describes the effects of the introduction of DCVTs in 6-10 kV distribution zones, and also provides criteria that allow us to assess in which cases the use of DCVTs and technologies based on them will be most beneficial. © 2024 IEEE.

关键词： Distribution transformers

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Ensuring Correct Relay Protection Functioning in Transient Modes With Saturation of Current Transformers 7

Ensuring Correct Relay Protection Functioning in Transient M...

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7th International Scientific and Technical Conference Relay Protection and Automation, RPA 2024

作者： Panashchatenko, A.V. Yablokov, A.A. Department of Electric Power Systems Automatic Control Ivanovo State Power Engineering University Ivanovo Russia

ISBN: (纸本)9798331501105

Electromagnetic current transformers, invented more than 100 years ago, are today the most widespread type of preliminary current converters, used in organizing metrological channels for commercial and technical electricity metering, measuring and relay protection systems. Despite their relatively simple design and modest price, today the question of using unconventional preliminary current converters (Rogowski coils, optical transformers, galvanic-magnetic sensors) is being increasingly raised [1]. This situation is due to the shortcomings of electromagnetic current transformers (CT): large weight and dimensions), explosion and fire hazard, and also saturation of their magnetic conductor in transient modes with the presence of an aperiodic component in short circuiting (SC) current. The phenomenon of saturation leads to significant distortion of the transmitted secondary signal, which in turn may become the cause of overprotection with external SC or delayed protection with internal SC. Russian and international practice in coordinating CT characteristics and relay protection requirements presuppose ensuring correct operation of relay protection systems not only in steady, but also in transient modes with possible saturation of CT magnetic conductors [2]-[5]. At present, testing the correct operation of relay protection and automation devices (RPAD) in transient modes is carried out using the CT saturation time, which under the specific conditions of the location of the CT should be more than the exact current conversion time required for correct operation of the connected RPAD. This time is calculated by special approved methods [2]. Such use of two extreme CT magnetic conductor conditions (saturated/unsaturated), without regard to the current waveform itself may lead to significant inaccuracies in evaluating the correctness of RPAD operation. Fig 1 shows two instances of saturation in one and the same CT in different operating conditions and with the same time be

关键词： Relay protection

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Processing Signals in Digital Current Measuring Transformers to Quickly Obtain the Vector for RPA Purposes

Processing Signals in Digital Current Measuring Transformers...

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2024 International Conference on Industrial engineering, Applications and Manufacturing, ICIEAM 2024

作者： Lebedev, Vladimir D. Grigorev, Denis G. Kuzmina, Nataliya V. Ivanovo State Power Engineering University Department Of Electric Power Systems Automatic Control Ivanovo Russia

ISBN: (纸本)9798350395013

In the development of secondary systems of stations and substations, including relay protection, automation, control, electric power metering and other features, there have recently been qualitative changes related to the introduction of digital technologies. The introduction of digital technologies is supported by innovative development programmes such as «Digital Transformation 2030». The essence of introducing digital technologies is related to the use of digital data transmission channels according to common standards. 'Digital substation' projects are being actively implemented with transmission of digital information at all levels, starting with primary equipment, including transmission of information, both from current and voltage measuring transformers, and switchgear. Currently, digital measuring transformers are being actively developed and beginning to be introduced, in which information on measured current and voltage is presented in a digital code. New approaches to measuring primary current and voltage, and the transmission of information pose new challenges and open up new prospects of improving signals processing methods used for relay protection purposes. This determines the relevance of the objective of our research - developing and studying approaches to the digital processing of signals in digital current and voltage measuring transformers. As a result, the approach to determining synchronized values of current vectors was studied by processing information obtained from primary current converters. The characteristics of the algorithm for obtaining the vector were analyzed, and the dependences of errors on the influence of distorting factors were plotted. The proposed approach to obtaining the vector is a development of the existing approach by obtaining information from current sensors operating on different physical principles. The study shows the advantages of the proposed method. © 2024 IEEE.

关键词： Relay protection

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Optimal Operation of Multi-Unit Diesel power Plant

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power Technology and engineering 2024年第4期58卷 592-597页

作者： Vasileva, A.A. Vaskov, A.G. Sigel, A.S. Shestopalova, T.A. Shurkalov, P.S. Laboratory of Control Systems for Solar-Diesel Plants National Research University "Moscow Power Engineering Institute" Moscow Russia Department of Hydraulic Power and Renewable Energy Sources National Research University "Moscow Power Engineering Institute" Moscow Russia

Methods of mathematical modeling of the dependence of fuel consumption on the load of diesel gensets are considered. Accounting for such dependence in simulating the operation of solar-diesel hybrid power systems can reduce the consumption of diesel fuel and the operating hours of diesel generators. © Springer Science+Business Media, LLC, part of Springer Nature 2025.

关键词： Diesel power plants

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Analysis of the Findings of the Study of the Time to Saturation of Current Transformer Magnetic Circuits Located at Electric power Facilities

Analysis of the Findings of the Study of the Time to Saturat...

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2024 International Ural Conference on Electrical power engineering, UralCon 2024

作者： Yablokov, Andrey Panashchatenko, Anton Ivanovo State Power Engineering University ISPU Department of Electric Power Systems Automatic Control Ivanovo Russia

ISBN: (纸本)9798350386028

Emergencies associated with incorrect operation of relay protection and automation (RPA) devices due to saturation of current transformers (CTs) can lead to great economic damage. The article presents an analysis of regulatory and technical documentation containing requirements for the quality of CT functioning in transient modes, statistical data on the results of calculations performed in accordance with the requirements of GOST R 58869-2019, as well as an analysis of the correctness of the assumptions introduced by it. To calculate the time to CTs saturation a special program was developed that automates the calculation methods, taking into account the assumptions focused on performing the manual calculations. The program takes into account the variation of the short circuit switching angle, the phase difference of the short circuit currents flowing through the branches feeding the short circuit point, the calculation of all CTs of a three-phase group with automatic selection of the worst result. The results obtained allow us to conclude about the relative number of CTs that do not meet the requirements of GOST R 58869-2019, the need to modernize existing methods and possible directions for such modernization. In addition, the article provides recommendations on the creation of automatic specialized software systems that can be used in the work of design, operating and research entities when they calculate the time to saturation of the CT magnetic circuits. © 2024 IEEE.

关键词： Transformer protection

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Model-Free Current Predictive control for PMSMs With Ultralocal Model Employing Fixed-Time Observer and Extremum-Seeking Method

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IEEE Transactions on power Electronics 2025年第8期40卷 10682-10693页

作者： Lin, Xinpo Liu, Jianxing Liu, Zhuang Gao, Yabin Peretti, Luca Wu, Ligang Harbin Institute of Technology Department of Control Science and Engineering Weihai264209 China Harbin Institute of Technology Department of Control Science and Engineering Harbin150001 China KTH Royal Institute of Technology Division of Electric Power and Energy Systems Stockholm10044 Sweden

Conventional model predictive current control of permanent magnet synchronous machines (PMSMs) relies heavily on a precise mathematical model, which may be challenging to obtain in certain cases. To address this issue, this article proposes a model-free predictive current controller for PMSMs. Specifically, the dynamic model of the motor currents is represented using two ultralocal models, which express the derivatives of a controlled output as the sum of an amplified control input and an unknown offset term. All system parameters, nonlinear terms, and unmodeled dynamics are encapsulated into two offset terms. Online estimation of these two offset terms is performed using a second-order fixed-time convergence observer without requiring exact knowledge of the system parameters in advance. In contrast to both the linear extended state observer and the super-twisting observer, the fixed-time observer enhances convergence speed while concurrently sustaining minimal chatting. To get rid of the need for model rated parameters, an extremum-seeking approach is utilized to tune the control gains in the ultralocal model, where the amplitude of the disturbance item in extremum-seeking approach is adaptively attenuated, resulting in effective reduction of the fluctuations of both the control gains and PMSM's currents in steady state. Subsequently, a predictive controller is designed using this ultralocal model. Finally, the effectiveness and advantages of the proposed control scheme are confirmed through experimental results. © 1986-2012 IEEE.

关键词： Permanent magnets

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