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2nd IEEE International Electrical and Energy Conference, CIEEC 2018

作者： Sui, Jiangyuan Zhang, Ling Zhou, Yuanxiang Zhang, Xinyan Cheng, Zixia Guo, Shaowei School of Electrical Engineering Xinjiang University Urumqi830047 China State Key Lab of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing100084 China State Key Lab of Electrical Insulation and Power Equipment Xi'an Jiaotong University Xi'an710049 China School of Electrical Engineering Zhengzhou University Zhengzhou450001 China Electric Power Research Institute State Grid Jibei Electric Power Company Beijing100045 China

ISBN: (纸本)9781538653913

The vinyl content in methyl vinyl silicone oil has a significant impact on the mechanical and electrical properties of reinforced silicone rubber. In this study, mechanical property and electrical tree initiation of silicone rubber were studied by comparing different vinyl contents. The results show that shore hardness, tensile strength, elongation at break, and tear strength of insulating silicone rubber material increase first and then decrease with the of vinyl content increasing from 1% to 5%. The breakdown strength and the initiation voltage of electrical tree are basically consistent with the variation of tensile strength and tear strength. Detailed discussion are presented. This work could provide data support for the practical preparation of engineering silicone rubber. © 2018 IEEE.

关键词： Tensile strength

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Wind farm active voltage regulation strategy of transient support improvement

Wind farm active voltage regulation strategy of transient su...

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8th Renewable power generation Conference (RPG 2019)

作者： Cui Yang Song Peng Cheng Xuekun Qiao Ying Wang Xiaosheng Liu Jingbo State Grid Jibei Electric Power Co. Ltd. Research Institute North China Electric Power Research Institute Co. Ltd. Xicheng District Beijing China Grid-connected Operation Technology For Wind-Solar-Storage Hybrid System State Grid Corporation Key Laboratory Xicheng District Beijing China State Key Lab of Control and Simulation of Power Systems and Generation Equipment Dept. of Electrical Engineering Tsinghua University Haidian District Beijing China

ISBN: (数字)9781839531248

ISBN: (纸本)9781839531255

The cumulative installed capacity of wind power worldwide has grown rapidly in recent years. Fixed reactive power control is adopted by wind turbines (WTs) to receive cycle instruction of wind farm (WF) automatic voltage control system (AVCS). It does not have active voltage regulation (AVR) capability, which reduces the reliability of power system operation. Firstly, two ways of WTs AVR which QV droop control and Vac control mode are introduced in this paper. On the basis, the problems of reactive power circulation and control points inconsistency during multi-WTs voltage regulation are discussed. The problems are solved by coordination of WTs of WF AVR strategy. WF voltage transient support capability is promoted by the strategy. Effectiveness is verified by simulation case of the proposed method.

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Statistical characteristics of transient enclosure voltage in ultra-high-voltage gas-insulated switchgear

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Plasma Science and Technology 2017年第6期19卷 74-81页

作者： Yuanji CAI Yonggang GUAN Weidong LIU State Key Lab of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 People＇s Republic of China

Transient enclosure voltage（TEV）,which is a phenomenon induced by the inner dielectric breakdown of SF_6 during disconnector operations in a gas-insulated switchgear（GIS）,may cause issues relating to shock hazard and electromagnetic interference to secondary *** is a critical factor regarding the electromagnetic compatibility of ultra-high-voltage（UHV）*** this paper,the statistical characteristics of TEV at UHV level are collected from field experiments,and are analyzed and compared to those from a repeated strike *** TEV waveforms during disconnector operations are recorded by a self-developed measurement system ***,statistical characteristics,such as the pulse number,duration of pulses,frequency components,magnitude and single pulse duration,are *** transmission line theory is introduced to analyze the TEV and is validated by the experimental ***,the relationship between the TEV and the repeated strike process is *** proves that the pulse voltage of the TEV is proportional to the corresponding breakdown *** results contribute to the definition of the standard testing waveform of the TEV,and can aid the protection of electronic devices in substations by minimizing the threat of this phenomenon.

关键词： transient enclosure voltage （TEV） gas-insulated switchgear （GIS） ultra-high-voltage （UHV） repeated strike process disconnector

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Skin Effect and Eddy Current Loss in Electrical Steel Sheets under Applied Excitation Fields.

Skin Effect and Eddy Current Loss in Electrical Steel Sheets...

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International Conference on Magnetics (INTERMAG)

作者： J. Li Q. Yang S. Wang Y. Li State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing China State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin China

Body: By applying electromagnetic diffusion equation, skin effect in electrical steel sheets in the condition of alternating excitation is analyzed based on Maxwell electromagnetic field theory. Due to skin effect is more significant mainly at high frequency, non-dimensionalized treatment for the diffusion equation is produced and eddy current loss is calculated by considering or not skin effect, respectively. Meanwhile, broadband magnetic losses and separation of typical electrical steel are obtained by using a 3-D magnetic properties testing system to bring to light the emergence of skin effect under rotational excitation. The simplification of magnetic constitutive equation is proposed and introduced into the diffusion equation, which is solved by employing finite elements coupled to Fredholm's equation. An approximate expression for the rotational eddy current loss component with skin effect is eventually written. The simulations show that due to the influence of skin effect, non-uniform distribution of induction flux density within electrical steel sheets will become more and more significant, the fl ux density and fi eld intensity nearby the surface are larger than that in the centre of the sheets [1, 2]. And with increasing of alternating excitation frequency, the inhomogeneity of induction flux density will be extended and growing more inhomogeneous, due to the smaller skin depth and a small increase of anomalous loss in the total core losses, as shown in Fig. 1.2. Therefore, alternating eddy current loss P as functions of the peak mean alternating flux density B mamean and the alternating excitation frequency f a can be deduced as follows: limv→∞P ae (B ma_mean f a )=[2ω a (B ma_mean ) 2 /3ρμν 2 =(σπ 2 d 2 /3ρ)(f a ) 2 (B ma_mean ) (no skin effect)[W/kg] (1) limν→0 P ae (B ma_mean f a )=[4ω a (B ma_mean ) 2 /ρμν=(4σ 1/2 π 3/2 d/ρμ 1/2 )(f a ) 3/2 (Bma_mean) 2 (considering significant skin effect) [W/kg] (2) where, ω a is the angular frequency; v = 2δ

关键词： Magnetics Conferences

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Losses Modeling Based on Domain Wall Processes and Valida-tion Considering Rotational Excitation of Electrical Steel Sheets.

Losses Modeling Based on Domain Wall Processes and Valida-ti...

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International Conference on Magnetics (INTERMAG)

On the basis of damping principle of vibration, the domain wall processes is investigated and modeled at low-to-medium frequencies in electrical steel sheets. Due to the energy dissipation chiefly descends from a micro-vortex current caused by domain wall motion, the coupled Landau-Lifshitz-Gilbert (LLG) and Maxwell electromagnetic diffusion equations are thus considered to describe the high-frequency characteristics. The overall core losses are eventually deduced in terms of separate contributions by domain wall processes and classical eddy current. Moreover, the calculation model can be extended to rotational excitation pattern. Hence, taking the typical electrical steel sheets as example, the novel core losses calculation model is analysed and compared with the total alternating core losses supplied by electrical steel sheets manufacturers and the 3-D rotating experimental core losses of sheets specimens which are carried out by using a 3-D magnetic properties testing system.

关键词： Magnetics Conferences

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A Novel Structure Design of Iron Core for power Transformers Considering Joints Forms and Magnetostriction.

A Novel Structure Design of Iron Core for Power Transformers...

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International Conference on Magnetics (INTERMAG)

作者： J. Li S. Wang H. Gao M. Liu J. Hong State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing China State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin China

Body: power transformers and reactors are important devices in power transmission systems. But their cores and windings could produce vibration and acoustic noise by magnetostrictive effect, Maxwell electromagnetic stress and Lorentz force. Noise has become a bad environmental pollution source in some situations, and its vibration and noise reduction has become an urgent problem need to be solved. The shapes, materials, magnetostriction and joints forms of iron cores, the limitations of test, modeling, and experimental measurement of vibration and noise characteristic, are all the difficult reasons to analyze the vibration and acoustic noise of transformers and reactors. 1. The magnetostrictive modeling can be divided into two steps based on the magnetic field force and materials deformation, so the magnetic field force will be fed into the structural finite element with Maxwell electromagnetic force produced on the interface between the iron core and the air to calculate the deformation of the magnetic materials and to make the model more general and consistent. In order to fully verify the correctness of the model in the magnetostrictive analysis, and to ensure the simplicity of test and avoid unnecessary interference factors, the most simple magnetostriction tests will be carried out by using a single closed circle or rectangular electrical steel sheet, as shown in Fig. 1(a). The tests will measure the relationship between magnetostriction and magnetic field of different magnetic materials, different saturations, different sizes and different shapes. 2. The joint is a necessary form for the stacking of large transformer iron cores, and the main joint form is the step jiont at present. The introduction of the joints causes the magnetic force lines to flow through the different laminations and to make the local magnetic field complicated. From simple to complex process is adopted in this paper, and the verification is gradually complicated. Based on the study of a

关键词： Magnetics Conferences

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MILP model for annual power and energy balance of hydro-thermal-wind power system considering RPS mechanism

MILP model for annual power and energy balance of hydro-ther...

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8th Renewable power generation Conference (RPG 2019)

作者： Danyang Zhao Wei Yan Cheng Luo Tian Luo State Key Laboratory of Power Transmission Equipment & System Security and New Technology (Chongqing University) Chongqing 400043 China Chongqing Electric Power College Chongqing 400050 China Key Laboratory of Control of Power Transmission and Conversion Ministry of Education (Shanghai Jiao Tong University) Shanghai 200240 China

ISBN: (数字)9781839531248

ISBN: (纸本)9781839531255

As more mandatory policies including Renewable Energy Portfolio Standard (RPS) in China have been introduced to promote renewable generations, traditional power balancing models may become no longer applicable to economically satisfy such ambitious goals. From the perspective of Chinese provincial power grid companies, proper scheduling could increase the penetration of renewable energy sources so as to meeting the urgent RPS requirements. In order to economically schedule annual power generations with consideration of RPS requirements and safety constraints, this paper proposes an annual power and energy balancing model of hydro-thermal-wind power system. The model aims to minimize the cost of power generation under the implementation of the RPS mechanism in China. Regional power grid's power balance constraints, the RPS constraints, hydropower monthly coordination as well as safety constraints including the operational characteristic constraints of hydropower, thermal power and wind power generator units have been considered. The model is formulated as mixed integer linear programming (MILP) problem, which is solved by CPLEX. Based on the data of a certain provincial power grid, the simulation results verify the effectiveness of the model.

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Optimal control of DERs in ADN under spatial and temporal correlated uncertainties

arXiv

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arXiv 2018年

作者： Chen, Xiaoshuang Lin, Jin Liu, Feng Song, Yonghua State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China

The control schemes of distributed energy resources (DERs) in active distribution networks (ADNs) are largely influenced by uncertainties. The uncertainties of DERs are complicated, containing spatial and temporal correlation, which makes it challenging to design proper control schemes, especially when there exist temporal-correlated units such as energy units (EUs). This paper provides an Itô process model to describe the characteristics of stochastic resources and EUs in a unified way, which makes it easy to evaluate the impacts of stochastic resources on temporal-correlated units. Based the moment form of the Itô process model, a moment optimization (MO) approach is provided to transform the stochastic control (SC) problem into an optimization problem with respect to the first-order and second-order moments of the system variables. The scale of MO is comparable to that of the corresponding deterministic control problem, which means that the computational efficiency of MO is much smaller than that of traditional approaches. Case studies also show that the proposed approach outperforms existing approaches in both the performance and computational efficiency, which means that the proposed approach has attractive potential for use in large-scale applications. Copyright © 2018, The Authors. All rights reserved.

关键词： Energy resources

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A Multi-Objective Model with Probability Constraints of Trans-Provincial Dynamic Stability Limit

A Multi-Objective Model with Probability Constraints of Tran...

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2019年第五届机械工程及自动化科技国际会议

作者： Ke Yang Rui Mao Xu Wen Chuncheng Gao Miao Huang Wei Yan Southwest Subsection of State Grid State Key Laboratory of Power Transmission Equipment & System Security and New Technology(Chongqing University) College of Automation Chongqing University of Posts and Telecommunications Beijing Ke Dong Electric Power Control System Co. Ltd. Nari Group Corporation/State Grid Electric Power Research Institute

With the rapid development of clean energy and serious delay of grid construction, water abandonment is becoming more and more severe. Under this condition, this paper proposed a multi-objective model with probability constraints of trans-provincial hydropower consumption considering dynamic stability limit. Firstly, a mathematical expression about the dynamic stability limit of trans-provincial channel is constructed. Secondly, a risk assessment index of abandoned water is established on the basis of semi-absolute deviation. Then, based on the framework of stochastic programming, a multi-objective model with probability constraints is proposed for hydropower transmission in trans-provincial trade. By means of genetic algorithm with embedded Monte-Carlo simulation technology, the model can be solved efficiently. Finally, data of Tibet power grid is calculated to verify the validity and universality of the research. The results show that the established model can achieve optimal economic benefit between grid companies and generation enterprises, and also effective management of water abandonment risk.

关键词： A Multi-Objective Model with Probability Constraints of Trans-Provincial Dynamic Stability Limit Model

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power and energy balance of active distribution network considering operation-control strategy

Power and energy balance of active distribution network cons...

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IEEE Conference on Energy Internet and Energy system Integration (EI2)

作者： Lin Cheng Ning Qi Lingxiao Wei Shaojun Xu Qingshi Liu State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China State Grid Beijing electric power company Beijing China

With the rapid deelopment of demand-side response and active distribution network, the new method to power and energy balance is becoming more and more important. In this paper, the architecture of power and energy balance in active distribution network is proposed, which consists of three parts: load and generation forecasting, power and energy balance. Moreover, capacity-load ratio guidance is modified combined with the peak shaving potential and trusted capacity. Besides, the energy balance method considering the operation-control of distributed energy is proposed. Finally, through numerical analysis, the feasibility and practicability of the model are verified.

关键词： Planning Forecasting Load forecasting Distributed power generation Dispatching Load modeling Capacity planning

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