Recently, DG (distributed generation) is rapidly developed around the world. But there are several problems in the grid-connected operation. The paper focuses on the selection of proper transformers to meet the ground...
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Recently, DG (distributed generation) is rapidly developed around the world. But there are several problems in the grid-connected operation. The paper focuses on the selection of proper transformers to meet the grounding requirements in the distribution networks. Through theory analysis and simulation, optimal selection methods are proposed. Yg/¿-connection transformer is suitable for small resistance grounding distribution networks while ¿ /Yg and ¿ / ¿ connection transformers are fit for small current neutral grounding networks. The conclusions are useful for the DG-connected power system.
As a clean, renewable, widely distributed, non-polluting energy, wind power plays an important role in the world's renewable energy development. In order to ensure the stable operation of wind turbines using non-g...
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As a clean, renewable, widely distributed, non-polluting energy, wind power plays an important role in the world's renewable energy development. In order to ensure the stable operation of wind turbines using non-grid-connected wind power, as well as the efficient utilization of wind resources, a study of condition monitoring of wind turbines is necessary. A test system of wind turbines under laboratory conditions based on a LabView platform has been designed and the system has been applied on small wind turbine test bed to test the performance of output power and vibration characteristics. The result of simulation testing has verified the effectiveness of the test system.
In order to fully understand the characters and working principles of non-grid-connected wind turbine, this paper makes an analysis on different methods for modeling non-grid-connected wind turbine. First, according t...
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In order to fully understand the characters and working principles of non-grid-connected wind turbine, this paper makes an analysis on different methods for modeling non-grid-connected wind turbine. First, according to the structure of the wind turbine, a theoretical model is presented, including three subsystems: rotor, transmission system and generator. Response of the model to a wind sequence is simulated. Then, based on the data gained from experiment, a model of small wind turbine is presented using system identification. The main content of the model is the performance coefficient Cp derived from experimental data. A comparison is made on the simulation results of the model and the data measured. With simulation results of the two methods for modeling wind turbine, by using theoretical analysis and identification respectively, we can see the two models are both effective; only that they should be applied in different conditions.
In this paper, fault mechanism of icing of wind turbine blades is studied theoretically and experimentally. First, the aerodynamic performance of a wind turbine's primary airfoil under normal and icing conditions ...
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In this paper, fault mechanism of icing of wind turbine blades is studied theoretically and experimentally. First, the aerodynamic performance of a wind turbine's primary airfoil under normal and icing conditions are simulated using Fluent software separately to analyze the geometry effect of icing on wind turbine. Then the formation and characteristics of vibration signal on main shaft caused by mass unbalance of wind turbine's rotor are analyzed using rotor dynamics theory to evaluate mass effect of icing on wind turbine. Finally, corresponding experiments are carried out on a self-made small wind turbine under laboratory conditions to testify the former theoretical analysis.
This paper is devoted to robust adaptive sliding mode control for a class of nonlinear systems in the Takagi-Sugeno forms with mismatched parametric uncertainties. Sufficient conditions for the existence of linear sli...
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To solve the weapon network system optimization problem against small raid objects with low attitude,the concept of direction probability and a new evaluation index system are *** calculating the whole damaging probab...
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To solve the weapon network system optimization problem against small raid objects with low attitude,the concept of direction probability and a new evaluation index system are *** calculating the whole damaging probability that changes with the defending angle,the efficiency of the whole weapon network system can be subtly *** such method,we can avoid the inconformity of the description obtained from the traditional index *** new indexes are also proposed,*** index,overlap index and cover index,which help manage the relationship among several *** normalizing the computation results with the Sigmoid function,the matching problem between the optimization algorithm and indexes is well ***,the algorithm of improved marriage in honey bees optimization that proposed in our previous work is applied to optimize the embattlement *** is carried out to show the efficiency of the proposed indexes and the optimization algorithm.
The rapid development of data mining supplies a new way for hydrological information analysis and mining, which use artificial intelligence methodology. Applying data mining theory and technology, we analysed hydrolog...
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