Advanced Materials Research Vols. 805-806

Abstract: This paper proposes a new method to predict the wind power of the distributed wind farms, considering the models such as the roughness model, the orography model. In order to predict the wind power accurately, this method calculates the loss of the wind speed directly, caused by the roughness model and the orography model. At the same time, this paper proposed the structure of the wind power prediction system, which provides the reference for the prediction of the wind power of distributed wind farms.

Abstract: Based on a case study of Jilin province in Northeast China, this paper applied input-output analysis method to contrast different effects of wind power and thermal power generation on local economic growth. The results indicate that the driving effect of wind power on economic growth in the output of per ten thousand Yuan is lower 5205 Yuan than that of thermal power. However, taking serious environmental externalities produced by thermal power generation into account, thermal power economic value will be greatly decreased.

Abstract: Based on the traditional single power control of the doubly-fed wind generator, this paper proposes an active/reactive power hybrid control method of the doubly-fed wind generator, which associates the operation characteristics of the doubly-fed wind generator with the operating conditions of the power grid. This proposed method incorporates the power variation in the system transmission channel into the calculation of the wind generator power output, and employs the additional control function of the wind generator to increase system damping and restrain system power oscillation. At the same time, the proposed method controls the wind generator to capture the maximum wind power when it is operating at a variable speed with a constant frequency. Moreover, because the proposed method decouples the control of active and reactive power, the converter capacity can be reduced. Simulations in a 9-generator 13-bus system and results indicate the effectiveness and robustness of the proposed method.

Abstract: In order to improve the ability of grid-connected wind power supplier to predict and manage risk, and analyze the economic benefit of wind power supplier, a model of bidding strategy for grid-connected wind power supplier is established based on the risk measurements indicator of the Conditional Value-at-Risk (CVaR). The model considering the trade-off problem between risks and benefits comprehensively which includes three risk factors as: fluctuated market price, uncertain load demand and random wind power output. By using the kernel density estimation method (KDE) on output forecast, this optimal model obtains bidding strategy and economic benefit of grid-connected wind power supplier under the impact of multistage risk in different risk preferences and compares the results with the impact of individual risk fluctuation.The calculation results show the validity of the proposed method.

Abstract: Analysis compares the direct access to a single set of wind power systemTwo groups of wind farm access system directlyMultiple sets of wind farm access system directly And Multiple sets of wind dispersion access system's impact on power system transient stability. And compare the simulation results, Concluded that wind farm access capacity and its topology structure's influence on system transient stability.

Abstract: As a kind of new green renewable energy, wind power is being paid more attention to by the countries in the world. Wind energy resource is rich in Hebei Province, and wind energy has great potential, so it is important for energy sustainable development, harmonious development of social economy and ecological environment to develop and utilize wind power in Hebei Province. In order to analyze the wind power industry competitiveness in Hebei Province scientifically and accurately, this paper introduced the tree-structured growing self-organizing map network (TGSMN) into the spatial data mining (SDM) to be used in spatial clustering. This method not only can make up the limitation of the more data limit and biggish computation in the common spatial data mining, but overcome the restriction of traditional maps that must appoint in advance. The wind power industry competitiveness evaluation in Hebei Province showed that the results given by this method are reliable.

Abstract: As one of the important renewable energy for relieving of the human energy crisis, the exploitation and utilization of wind energy, and the encouragement of wind power industry help to realize the development of low-carbon economy in China. In the past few years, the wind power industry has achieved rapid development which faces a lot of opportunities as well as many challenges in china. Using SWOT analysis method, this paper indicates the advantages and disadvantages, and analyzes the opportunities and challenges. This study not only helps to understand the status of the industry, but also provides valuable information to promote the future development of the wind power industry in China.

Abstract: One critical task in wind turbine shaft torsional vibration study involves the modelling of wind turbine and power grid. Focus on the mechanical rotational system of wind turbine, this paper provides three-mass shaft model upon which one wind turbine to infinite bus model can be developed. The model based on small signal stability analysis is used to study the wind turbine shaft torsional vibration. For this reason, this paper concentrates on the union model of stall wind turbine and power grid. The small-signal stability model includes the mechanical system and electrical system. Each of the component-blocks of the wind turbine and power grid is modelled separately so that one can easily expand and modify the model to suit their needs. Then, this is followed by one case study to explain how the small-signal stability model can be used to study wind turbine shaft torsional vibration issues.

Abstract: Todays power system is integrating increasingly variable and uncertain generation resources, especially wind power. As much of wind generators in the market contribute little or none to system inertia, power system is operated much closer to its dynamic security margin. To identify the maximum wind penetration of a power system following a pre-defined disturbance, the impact of increased wind penetration on post-disturbance stability is studied. In this paper, the disturbance is simulated by a short circuit that leads to the sudden disconnection of a large amount of load demand. When wind power covers a small portion of system demand, the post-disturbance frequency is not much affected by grid-connected wind generators. But when wind penetration is increased to a comparative high level, power system loses stability in the form of undamped frequency oscillation. Simulation results show that, in the occurrence of system disturbances, 60% feed-in wind penetration will make the power system loses stability. Anyway, taking into consideration of simulation accuracy, severity of disturbances and diversity of power systems, 60% must not be a precise result, it could just be used as a reference when analyzing other grids.

Abstract: The performance of doubly fed induction generator (DFIG) based wind turbines supplying local isolated load is manly up to the stator-voltage control strategy. Compared with conventional steady mathematic model based one, a dynamic mathematic model based stator-voltage decoupling control strategy was proposed in the paper, by which the accuracy of stator voltage was improved greatly. In this paper, the dynamic mathematic model of stator voltage and then the proposed stator-voltage decoupling control were deduced, based on which the corresponding decoupling control strategy was designed and analyzed. At last, the stator-voltage decoupling control strategy for DFIG based wind turbine supplying local isolated load was achieved. To validate the design and analysis, the simulation model was built in the Matlab/Simulink environment, and some important results were reported in the paper.