Compared with other conventional energy sources,renewable energy,which results in less pollution and has numerous resources,is a significant factor in addressing the current issues of the serious environmental polluti...
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ISBN:
(纸本)9781509009107
Compared with other conventional energy sources,renewable energy,which results in less pollution and has numerous resources,is a significant factor in addressing the current issues of the serious environmental pollution and the resource ***-scale renewable energy connected to the grid could lead to a the change of the morphological structure and the operation modes of energy *** current power grid evolution models did not consider the characteristics of renewable energy in the evolution *** expansion mechanism of the future transmission network with a high proportion of renewable energy is studied in this *** operation cost including renewable energy curtailment are optimized using the production simulations,where the stochastic and intermittent of wind and solar energy are *** the dual variable information is adopted to drive the grid *** expansion strategies for power grid of Zhejiang province in China are analyzed to balance the construction cost and curtailment cost of renewable energy.
With the development of energy industry and infor-mation technologies, the concept of energy Internet is proposed to prevent the energy crisis and reduce the environmental pollution. However, the planning of energy In...
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ISBN:
(纸本)9781538614280
With the development of energy industry and infor-mation technologies, the concept of energy Internet is proposed to prevent the energy crisis and reduce the environmental pollution. However, the planning of energy Internet is facing great challenges that there are large uncertainties of boundary conditions in the planning. The collection of Internet information can help solve the problem. This paper introduces the method of collecting objective data from the Internet, such as renewable energy sources data, climate data, and economic data, and the usage of the data for energy Internet planning. The method of collecting and processing fuzzy information from the Internet are introduced as well. The events related to the energy Internet planning can be perceived and be applied to the multi-scenario planning of energy Internet. Besides, the difficulties and outlooks of the usages are given.
Very fast transient over-voltage （VFTO）, induced by disconnector operations in gas- insulated switchgears, has become the limiting dielectric stress at ultra-high voltage levels. Much work has been done to investiga...
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Very fast transient over-voltage （VFTO）, induced by disconnector operations in gas- insulated switchgears, has become the limiting dielectric stress at ultra-high voltage levels. Much work has been done to investigate single-strike waveforms of VFTO. However, little study has been carried out investigating the repeated strike process, which would influence VFTO significantly. In this paper, we carried out 450 effective experiments in an ultra-high voltage test circuit, and conducted calculations through the Monte Carlo simulation method, to investigate the repeated strike process. Firstly, the mechanism of the repeated strike process is proposed, based on the ex- perimentai results. Afterwards, statistical breakdown characteristics of disconnectors are obtained and analyzed. Finally, simulations of the repeated strike process are conducted, which indicate that the dielectric strength recovery speed and polarity effect factor have a joint effect on VFTO. This study enhances the understanding of the nature of VFTO, and may help to optimize the disconnector designed to minimize VFTO.
With the rapid development of local generation and demand response,the active distribution network(ADN),which aggregates and manages miscellaneous distributed resources,has moved from theory to *** and optimal operati...
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With the rapid development of local generation and demand response,the active distribution network(ADN),which aggregates and manages miscellaneous distributed resources,has moved from theory to *** and optimal operations now require an advanced situation awareness(SA)system so that operators are aware of operation states and potential *** solutions in distribution supervisory control and data acquisition(DSCADA)as well as the distribution automation system(DAS)generally are not able to meet the technology requirements of *** this paper,the authors’participation in the project of developing an SA system as the basic component of a practical active distribution management system(ADMS)deployed in Beijing,China,is *** paper reviews the ADN’s development roadmap by illustrating the changes that are made in elements,topology,structure,and control *** into consideration these hardware changes,a systematic framework is proposed for the main components and the functional hierarchy of an SA system for the *** SA system’s implementation bottlenecks are also presented,including,but not limited to issues in big data platform,distribution forecasting,and security *** technology solutions are also provided.
This paper proposes a novel active stabilization method based on reshaping the output impedance of the source-side PWM rectifier for More Electric Aircraft (MEA) powersystem. A nonlinear compensation signal is inject...
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ISBN:
(纸本)9781509012114
This paper proposes a novel active stabilization method based on reshaping the output impedance of the source-side PWM rectifier for More Electric Aircraft (MEA) powersystem. A nonlinear compensation signal is injected into AC voltage command of PWM rectifier to adding a virtual resistor paralleled with DC bus capacitor. Thus, the instability caused by constant power loads (CPLs) can be neutralized. Compared to conventional active damping methods, the value of compensation signal can be expressed by the virtual resistor so that the physical mechanism of stability improvement can be clarified. Besides, all remote sensors providing load input voltages can be removed. Stability and sensitivity of the proposed active stabilization method are analyzed qualitatively. The interaction dynamics of passive devices, such as LC filters of CPLs and DC capacitors on source side are discussed. simulation results validate the effectiveness of the proposed method.
High impedance faults (HIFs) are easy to occur in collective feeders in wind farms and may cause the cascading of wind generators tripping. This kind of faults is difficult to be detected by traditional relay or fuse ...
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ISBN:
(纸本)9781785618260
High impedance faults (HIFs) are easy to occur in collective feeders in wind farms and may cause the cascading of wind generators tripping. This kind of faults is difficult to be detected by traditional relay or fuse due to the limited fault current values and the situation is worse in wind farms. The mostly adopted HIF detection algorithms are based on the 3rd harmonic characteristic of the fault zero-sequence currents, whereas these 3rd harmonics are very easy to be polluted by wind power back-to-back converters. To solve this problem, the typical HIF arc flash based on Mayr's arc model is first built, and the typical fault waveforms of HIF in wind farm are presented. Then the characteristics of high impedance faults are analysed to distinguish the occurrence of HIF from other harmonic interference. After that, the performance of the traditional harmonic based HIF detection algorithm is discussed, and a novel detection algorithm is presented to prevent harmonic interference influence in wind farms.
Under the situations of energy crisis around the world, Energy Internet has become the focus of international academic and industrial areas. In this paper, comprehensive reviews and prospects were made based on the ba...
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ISBN:
(纸本)9781538614280
Under the situations of energy crisis around the world, Energy Internet has become the focus of international academic and industrial areas. In this paper, comprehensive reviews and prospects were made based on the background and current research status of Energy Internet. Moreover, the core concept, basic structure, and operation mode of Energy Internet were introduced and discussed. Finally, constructive solutions to the current problems were proposed with the demonstration project of Energy Internet that is the Beijing New Aerotropolis, which draws the future of the Energy Internet.
In this paper, we consider the design of linear precoding in Multiple Input Multiple Output （MIMO） power Line Communication （PLC） systems with finite-alphabet input. First, we derive mutual information of MIMO-PLC...
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In this paper, we consider the design of linear precoding in Multiple Input Multiple Output （MIMO） power Line Communication （PLC） systems with finite-alphabet input. First, we derive mutual information of MIMO-PLC systems with impulsive noise. Considering the non-concavity of the objective function and the low-cost requirement of PLC systems, we choose the lower bound of the mutual information as the objective function. Subsequently, we propose a novel approach to design the precoding scheme to reduce computational complexity. Specifically, our work primarily includes the following two contributions： （1） We design the right unitary matrix that is a product of two fixed unitary matrices, which only depends on the modulation mode. Hence, the results can be saved and require less computations. （2） For the power allocation matrix, we first reduce the space of power allocation using constraints of the optimal power allocation policy. Consequently, we propose a non-linear search method to obtain the optimal power allocation in small space. In regards to the computational complexity of the analysis, we conclude that the proposed precoding matrix design scheme has low complexity and is easy to implement. Moreover, the numerical results are proven to demonstrate the performance of the proposed precoding design scheme.
Half-wavelength AC transmission (HWACT) is an ultra-long distance AC transmission technology, whose electrical distance is close to half-wavelength at the systempower frequency. The countries with a large territory h...
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ISBN:
(纸本)9781509041695
Half-wavelength AC transmission (HWACT) is an ultra-long distance AC transmission technology, whose electrical distance is close to half-wavelength at the systempower frequency. The countries with a large territory have a big demand for HWACT. The fault characteristics of an HWACT line can be different from those of a conventional transmission line. So it is necessary and significant to analyze the fault characteristics of an HWACT line. In this paper, the influence of fault distances and fault resistances on the fault voltages and currents of two buses is analyzed after different types of faults occur on an HWACT line. And the analysis results are compared with the simulation results from EMTP.
As for aero-engine,it is relatively difficult to obtain the displacement signal,only to measure the acceleration *** the paper,aimed at the dual-rotor system test rig,the rub-impact is simulated and the acceleration s...
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ISBN:
(纸本)9781510868434
As for aero-engine,it is relatively difficult to obtain the displacement signal,only to measure the acceleration *** the paper,aimed at the dual-rotor system test rig,the rub-impact is simulated and the acceleration signals collected from the bearing pedestal are analysed to extract the rubbing faults' ***-component extraction is an available method for vibration signal analysis of rotary machinery,so a novel method of rubbing fault diagnosis based on variational mode decomposition(VMD) is *** is a newly developed technique for adaptive signal decomposition,which can non-recursive decompose a multi-component signal into a number of quasi-orthogonal intrinsic mode *** the rub-impact fault occurs in the dual-rotor system,the acceleration vibration signals of the dual-rotor system will present amplitude-modulated feature because of the periodic rub-impact between the rotor and the *** is then applied to detect multiple rubbing-caused signatures for rotor-stator fault diagnosis via practical vibration *** using VMD,the rub-impact signal,background signal and noise signal can be separated efficiently and the fault feature of vibration signal of a rotor system with local rub-impact fault can be ***,the VMD method can be applied to the rub-impact fault diagnosis of the rotor systems efficiently.
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