Advanced Materials Research Vols. 724-725

Abstract: There is a certain degree of correlation between the outputs of different wind farms because of their geographic distribution in power grid. And the complementary effect can alleviate the adverse effects of peak-load regulation caused by the large-scale wind power integration. In this paper, Nataf transformation was used to establish wind speed samples of correlative wind farms to get correlative wind power. Based on this, the peak-load regulating adequacy was evaluated using Monte-Carlo method on IEEE-RTS system with wind farms. The result presents the quantitative analysis of the impact of correlative wind farms on peak-load regulating adequacy. And it improves the original peak-load regulating adequacy evaluation based on Monte-Carlo method, which has the relatively conservative results.

Abstract: The objective of this research is to study the small multi-blades windmill for water pumping by using a studying performance of windmill which has a curvature plate ratio of 0.07 and determine overall efficiency and evaluate economic of the system. The results from the test run of windmill rotor model in the wind tunnel at a wind velocity of 3 m/s, the windmill give maximum power coefficient of 0.296 at a tip speed ratio of 1.18. The results from the test run of the windmill-pump system at 2 m head have an overall efficiency of 0.239 at the wind velocity of 1.2 m/s. The output of 2.38 L/min, which implies a rate of return for water pumping at 0.038 USD per cubicmetre of water base on 10 year-life time of windmill.

Abstract: Compared to nuclear power, wind power has a short construction period, high security, rich in resources and other advantages; compared to photovoltaic power generation, wind power has the power and low cost advantages. Over the past five years, benefit from the support of the localization rate and other policies, the average annual wind power in China compound growth rate of 101%, wind power industry chain upstream parts manufacturing localization, spindle bearings, control systems also need to be imported; midstream machine manufacturing market dominated by domestic-funded enterprises; downstream wind power operators also see five power generation groups, led by the central enterprises the wind turbine increasing unit capacity of 1.5MW and above the level of wind turbine occupy a major share of the market, the development of wind power is inseparable from the support of the policy. Offshore wind power has high feed-in tariff, high throughput advantage of offshore wind power will become a growth point of the wind power industry in the future.

Abstract: This paper analyses the control strategy of different wind turbine power limitation in high winds. And the active power regulation method is summarized into: Start-Stop control, yaw control and pitch control. There are also some analysis and comparison of these three methods. It is pointed out that if the wind farm's main control system of wind turbine cant be modified, Start-Stop control strategy can be used for limiting the power via remote monitoring. Accordingly, this article provides a feasible start-stop control strategy. For the wind turbine whose main control system can be modified, this article gives feasibility analysis of yaw control and pitch control application. And only pitch control solution is suitable for limiting the active power. Accordingly, pitch control strategy is given in detail.

Abstract: VSC-HVDC has become prior transmission way in delivering off-shore wind power. This paper studies offshore wind system based on DFIG (Doubly Fed Induction Generator) wind turbine. The control strategy of the system during the normal and fault condition are studied. In the normal condition, the GSVSC are operated by controlling constant frequency, voltage and phases. During the fault condition, the GSVSC converted to limit current model and dc voltage link are controlled by DFIG-RSC converter. These control strategies are validated in good performance in PSCAD/EMTDC platform.

Abstract: Voltage fluctuation and flicker are among the most serious impacts of wind power generation on power quality. To assess and suppress voltage fluctuation and flicker, an accurate detection method is necessary. According to characteristics of flicker caused by wind farm, a systematic, accurate and fast flicker detection method was introduced. First, with Mathematical Morphology (MM) filter, noises contained in flicker signal were filtered out. Then to the filtered flicker curves, a track method based on Hilbert transform was adopted to pick out the flickers envelope which is the base of attaining relevant parameters of flicker. At last, the envelope was simultaneously analyzed in both time-domain and frequency-domain by a novel non-stationary signal processing method, the Hilbert-Huang transform (HHT). Simulations show that with this method, time, frequency and amplitude information of non-stationary flicker signals can be accurately detected and the proposed method is effective in the analysis of flickers caused by wind farm.

Abstract: Offshore wind power is expected to increase significantly in the near future. This document use the method combined the SWOT and fuzzy comprehensive appraisal to analyze China’s offshore wind industry competitiveness. Firstly, perform qualitative analysis by SWOT and then use fuzzy comprehensive appraisal to transfer qualitative analysis to quantitative analysis for a more objective and accurate evaluation. The final evaluation results show that China’s offshore wind industry is competitive. And China should actively and steadily promote the development of offshore wind industry while should pay attention to draw experience and lessons from onshore wind power.

Abstract: in this work, a model for variable-pitch wind power generation controller system is set up. The model is simulated under MATLAB / Simulink environment. The simulation result shows that adding adjustable variable-pitch wind turbine can significantly improves the stability of the generator speed and output power. This work can provide a reference for correlative study on wind power generation system.

Abstract: A Numerical simulation on the influence of airfoil surface contamination on the aerodynamic performance of wind turbines was performed. It chose the dedicated wind turbine airfoil as the research object. The k-ω Shear Stress Transmission (SST) turbulence model was selected for CFD calculation. The roughness height which arranged evenly on the airfoil was changed from 0.03mm to 2.0mm to obtain the sensitive roughness. The airfoil was divided into 18 sections for analyzing the effect on the lift & the drag coefficient, due to various locations of sensitive roughness. By comparing the result computed by XFOIL and CFD calculation, it can be known this airfoils sensitive locations in suction surface and pressure surface. The sensitive locations in suction surface were 53% and 92% from the chord line towards the leading edge, while 44% and 88% in pressure surface. The sensitive roughness in sensitive locations delayed the location of the transition point.

Abstract: According to the demand of wind farm power fluctuations stabilize and the characteristics of hybrid energy storage system. Taking vanadium redox flow battery (VRB) and supercapacitor (SC) as research object, a hybrid energy storage system optimal configuration model is builted. Combined with expert systems and improved genetic algorithm proposed a hybrid energy storage system to optimize the allocation method. The method first established desire output curve of the wind farm based on grid energy saving efficiency and static voltage stability indicators, then introduce coordinate control strategy based on expert system to improved genetic algorithm to get the result of optimal configuration and verify the correctness of this model and method. Finally, analysis the performance of VRB and SC in a typical days wind farm output situation, verify the conclusions of experts coordinated control strategy can extend the vanadium battery life.