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11th IET International Conference on Advances in power system control, Operation and Management, APSCOM 2018

作者： Lin, Qunli Shen, Xinwei Xu, Yinliang Sun, Yong Li, Zhenyuan Guo, Qinglai Sun, Hongbin Shenzhen Environmental Science and New Energy Technology Engineering Laboratory Tsinghua-Berkeley Shenzhen Institute Tsinghua University Shenzhen China Jilin Power Grid Company State Grid Corp. of China Jilin China State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781839530043

Integrated Energy system (IES), which plays a vital role in the development of Energy Internet (EI), can improve the efficiency of energy utilization and integration of renewable energy. However, the coupling between multiple energy systems will bring new challenges to the security control of the IES, such as combined heat and power (CHP) system. For IES, the preventive control is the first line of defense to ensure that the system can keep stable operation when contingencies such as the transmission outage or generator outage happen. This paper proposes a preventive control approach for CHP system, in which a day-ahead security constrained economic dispatch (SCED) model of CHP system considering the coupling of heat and electric is formulated. The model aims to minimize the cost of the whole system, while the preventive control of the system can be achieved with the constraints considering the normal states and contingencies states. Case studies based on the IEEE 9-bus system with CHPs are presented to illustrate the approach. The case result shows that the combined electric and heat optimal dispatch is more economical than when two systems are independently optimized and operated. And the proposed preventive control approach of the CHP system can satisfy both the electric and heat demand, and system security is ensured when the N-1 contingencies happened. © 2018 Institution of Engineering and Technology. All rights reserved.

关键词： Internet of Energy

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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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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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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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Coordinated analysis of urban integrated energy-traffic networks based on real-world GPS data

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Energy Procedia 2018年 152卷 490-495页

作者： Tianyu Yang Qinglai Guo Chenhui Lin Luo Xu Hongbin Sun Department of Electrical Engineering Tsinghua University 100084 Beijing China State Key Lab of Control and Simulation of Power Systems and Generation Equipments 100084 Beijing China

The rapid growing scale of electric vehicles (EV) has brought benefit and impact on urban traffic network and the electric power system simultaneously by integrating these two systems together into a Cyber-Physical-Social system (CPSS) in energy. This paper presents a coordinated analysis method of the urban integrated energy-traffic network based on real-world GPS data from vehicles in Shenyang and Shenzhen, China. Case study shows that the integrated system will be affecting each other through the coupling interactions of EVs.

关键词： Electric vehicles (EV) Urban traffic network Cyber-Physical-Social system

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Demand Side Data Generating Based on Conditional Generative Adversarial Networks

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Energy Procedia 2018年 152卷 1188-1193页

作者： Jian Lan Qinglai Guo Hongbin Sun Department of Electrical Engineering Tsinghua University 100084 Beijing China State Key Lab of Control and Simulation of Power Systems and Generation Equipments 100084 Beijing China

With the technological advancement in the fields of advanced metering infrastructure (AMI), a massive amount of customers’ electricity consumption data is collected. Meanwhile, the energy providers need to make informed decisions based on power consumption strategy of demand side to reduce overall operational cost. So how to generate demand side load data based on historical energy consumption data or customer attribute is a pressing issue. In this paper, we propose a data-driven approach to generate new power consumption data based on intrinsic property of load pattern learnt from demand side using conditional generative adversarial networks (cGANs), which is based on two interconnected deep neural networks known as generator and discriminator. By using several representative labels from the responded surveys and the load data from demand side to train the models, the generator is able to generate realistic power consumption data by given labels which can be used for energy management and scheduling, the discriminator is capable of detecting abnormal power consumption and system error from the smart meter data.

关键词： conditional GANs generative models demand side smart meter data analysis energy management

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Misalignment fault detection in dual-rotor system based on time frequency techniques

Misalignment fault detection in dual-rotor system based on t...

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Society for Machinery Failure Prevention Technology Annual Conference 2017: 50 Years of Failure Prevention Technology Innovation, MFPT 2017

作者： Wang, Nan-Fei Jiang, Dong-Xiang Han, Te State Key Laboratory of Control Simulation of Power System and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing100084 China

In order to improve the energy efficiency and compact structure, the dual-rotor structure including lowpressure rotor and high-pressure rotor has been widely used in aero-engine. Misalignment is one of the most common faults in dual-rotor system, which will causes malfunctions. It is a significant task for rotor dynamics personnel to monitor and defect faults in dual-rotor system. In the paper, the dual-rotor vibration signals are applied to solve the fault identification problem by utilizing time frequency techniques. Numerical simulations are carried out through finite element analysis of dual-rotor system with misalignment fault. Two signal processing tools namely Short Time Fourier Transform (STFT) and Continuous Wavelet Transform are used to detect the misalignment fault and compared to evaluate their diagnosis performance. The effect of addition of Signal to Noise (SNR) on three frequency techniques is presented. Experiments are carried out to obtain the vibration data of dual-rotor test rig and the results from the work show that the technique can be used for the monitoring of misalignment, which will have applications in the condition monitoring and maintenance of various types of rotating machinery.

关键词： Condition monitoring

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Space Charge Behavior in AC Electrically Aged Low-Density Polyethylene Films

Space Charge Behavior in AC Electrically Aged Low-Density Po...

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China International Electrical and Energy Conference (CIEEC)

作者： Zixia Cheng Jinxing Shi Ling Zhang Yuanxiang Zhou Zekai Lu Shaowei Guo School of Electrical Engineering Zhengzhou University Zhengzhou China State Key Lab of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China Electric Power Research Institute State Grid Jibei Electric Power Company Beijing China

ISBN: (纸本)9781538653937

In order to study the effect of AC aging on space charge characteristics of low-density polyethylene (LDPE) films, an AC electric field of 50 kV/mm (peak value) was adopted for the accelerated aging test and space charge measurements of AC aged LDPE films were carried out subsequently. The results show that no significant space charge accumulation in the LDPE samples aged under a 50 kV/mm AC electric field. It can be seen that a significant positive space charge accumulation occurs inside the sample, when DC electric fields were applied to the AC aged LDPE samples. The long-term AC aging also causes more and deeper cracks on the surface of LDPE samples. Moreover, AC aging promotes the oxidation reaction of LDPE. The longer the aging time, the higher the degree of oxidation. On this basis, the probable relationship between space charge characteristics and material physicochemical properties of LDPE during AC electrical aging is clarified.

关键词： Aging Space charge Electric fields Anodes Insulation Polyethylene

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