This paper presents an optimal power flow model for AC/DC meshed networks with modular multi-level converter based HVDC transmission system (MMC-OPF). The MMC-OPF problem is formulated to minimize the total network lo...
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ISBN:
(纸本)9781509054190
This paper presents an optimal power flow model for AC/DC meshed networks with modular multi-level converter based HVDC transmission system (MMC-OPF). The MMC-OPF problem is formulated to minimize the total network loss of the whole AC/DC grids by adjusting generators and converters. In addition, a practical method is proposed to consider N-1 static security constraints with OPF calculation. Case studies of IEEE testing system and a practical network have been carried out. The results demonstrate the effectiveness of the method.
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 poll...
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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 depletion. Large-scale renewable energy connected to the grid could lead to a the change of the morphological structure and the operation modes of energy transmission. While current power grid evolution models did not consider the characteristics of renewable energy in the evolution strategy. The expansion mechanism of the future transmission network with a high proportion of renewable energy is studied in this paper. The operation cost including renewable energy curtailment are optimized using the production simulations, where the stochastic and intermittent of wind and solar energy are modeled. And the dual variable information is adopted to drive the grid upgrading. The expansion strategies for power grid of Zhejiang province in China are analyzed to balance the construction cost and curtailment cost of renewable energy.
When there is power supply shortage or emergency event in powersystem, orderly power utilization needs to be applied to cut down electricity demand to maintain power supply for important electricity consumers. Curren...
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By using theoretical and experimental methods, dynamic characteristics of turbine blades with integral shrouds are studied, and the mechanism of vibro-impact and the effective factors of integrally shrouded blades are...
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By using theoretical and experimental methods, dynamic characteristics of turbine blades with integral shrouds are studied, and the mechanism of vibro-impact and the effective factors of integrally shrouded blades are mainly presented. By means of finite element calculation, the dynamic frequencies and vibration mode shapes of single shrouded blade are explored under different rotating speeds. The three-dimensional entity unit integral dynamics equation of blades with vibro-impact are established by using nonlinear damping model in this paper. With the help of 3D software Solidworks, the solid model of blade is built. With the aid of FEA software ANSYS, the dynamics and static characteristics of single blade are obtained. Meanwhile, by building the model to set different shroud clearance and exciting force amplitude, the relationships between displacement of blade tip and influence of such as blade shroud clearance and exciting force amplitude are demonstrated. The results of the analysis indicate that the collision structural is an ideal damping structure. As the clearance between blade shrouds is smaller, the damping effect is better. Moreover, results show that blades adopting collision damping mechanism can achieve good damping effect when the blades are subjected to greater exciting force.
The measured parameters change with the machine degradation, where the trends of the parameters can be applied in condition prediction. The deterioration of the parameters usually present characteristics in a monotoni...
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The measured parameters change with the machine degradation, where the trends of the parameters can be applied in condition prediction. The deterioration of the parameters usually present characteristics in a monotonic or low-frequency way. As the measure signal are merged with instant signals, noise and measurement error in different frequency bands, model decomposition approaches are widely applied to separate the different bands for feature extraction. Among the model decomposition methods, Variational model decomposition is recently proposed by K. Dragomiretskiy and D. Zosso as a non-recursive model which can extract modes concurrently. This work will analyze its effectiveness in degradation feature extraction and application in condition prediction in prognosis. Firstly, variational model decomposition is analyzed, where the characteristics of variational model decomposition are compared with another mode decomposition method ensemble empirical mode decomposition. simulation data is applied to test the effectiveness of the mode decomposition methods. Secondly, field data with component degradation is collected, and the degradation feature extraction is applied with the three methods mentioned above.
An active distribution systempower-supply planning model considering cooling,heating and power load balance is proposed in this paper.A regional energy service company is assumed to be in charge of the investment and...
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An active distribution systempower-supply planning model considering cooling,heating and power load balance is proposed in this paper.A regional energy service company is assumed to be in charge of the investment and operation for the system in the *** expansion of substations,building up distributed combined cooling,heating and power(CCHP),gas heating boiler(GHB)and air conditioner(AC)are included as investment planning *** terms of operation,the load scenarios are divided into heating,cooling and transition ***,the extreme load scene is included to assure the power supply reliability of the *** results demonstrate the effectiveness of the proposed model and illustrate the economic benefits of applying distributed CCHP in regional power supply on investment and operation.
This paper uses the least squares method,BP neural network and gray GM(1,1) model for trend forecasts and predicting the remaining life of the aero-engine fault *** comparing the results of the three methods,the least...
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ISBN:
(纸本)9781510806474
This paper uses the least squares method,BP neural network and gray GM(1,1) model for trend forecasts and predicting the remaining life of the aero-engine fault *** comparing the results of the three methods,the least squares method and BP neural network method predicting results are more exact than the gray GM(1,1) *** three methods are also used for predicting the actual data,and the result is close to the real.
Wind powergeneration uncertainty has imposed great challenge on powersystems' operation and should be considered when making an operation *** this paper,we focus on optimal power flow(OPF) problem in radial powe...
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ISBN:
(纸本)9781467374439
Wind powergeneration uncertainty has imposed great challenge on powersystems' operation and should be considered when making an operation *** this paper,we focus on optimal power flow(OPF) problem in radial power networks while considering wind powergeneration *** cope with this uncertainty,the stochastic AC-constrained OPF(ACOPF) problem considering both continuous and discrete devices is formulated based on our previous *** second order cone relaxation is employed to relax the original mixed integer nonconvex nonlinear programming(MINNLP) problem to a mixed integer second order cone programming(MISOCP) problem which can be solved by commercial solvers with high computation *** modified IEEE 33 bus distribution system is studied in this paper which validate the effectiveness of the proposed model.
Time-varying frequency selective attenuation and colored noises are unfavorable characteristics of power line communication(PLC) channels of the low voltage *** overcome these disadvantages,a novel real-time dynamic s...
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Time-varying frequency selective attenuation and colored noises are unfavorable characteristics of power line communication(PLC) channels of the low voltage *** overcome these disadvantages,a novel real-time dynamic spectrum management(DSM) algorithm in orthogonal frequency division multiplexing(OFDM)-based high-speed narrow-band power line communication(HNPLC) systems is proposed,and the corresponding FPGA circuit is designed and *** of the proposed DSM is validated with a large amount of network experiments under practical PLC *** the noise in each narrow subcarrier is approximately Gaussian,the proposed DSM adopts the BER/SER expression formulized via the AWGN channel to provide a handy and universal strategy for power *** real-time requirement is guaranteed by choosing subcarriers in group and employing the same modulation scheme within each *** measures are suitable for any modulation scheme no matter the system criterion is to maximize data rate or minimize power/*** design and hardware implementation of the proposed DSM are given with some flexible and efficient *** DSM circuit is carried out with Xilinx *** and practical experiments validate that the proposed real-time DSM significantly improves system performance.
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