Advanced Materials Research Vols. 953-954

Abstract: In the paper the models of IG and DFIG have been analyzed, and then the two reactive power compensations SVC and STATCOM have been introduced. Finally, use the simulation software of power system PSCAD to simulate the process of wind power integrating into grid. In the simulation results, it’s obvious that the DFIG has better transient stability than IG; install SVC or STATCOM can improve transient stability of wind farm, but SVC is apt to cause harmonic pollution, and STATCOM can improve transient stability to both kinds of generators.

Abstract: In this paper, the security and consumption problems of large-scale wind power integration to electric grid are briefly introduced, focusing on serious events that many installations went off the grid, failing to “ride through fault” (RTF), which happened successively since 2011. Then the mechanisms of coordinated development between wind power and electric grid are discussed, and suggestions on management & technical measures are proposed to realize a great friendly wind farm which can be developed in a scientific, healthy and sustainable manner.

Abstract: Wind power is a new technology compared with thermo power, the damage of sub-synchronous oscillations cloud bring to the shaft of wind turbine do not get enough notices. There are few studies on wind turbines sub-synchronous oscillation now, which are built on the model of rigid shaft. As we all know wind turbine shaft is unlike the shaft of stream turbine, there are couplings and gearbox in wind turbine which make the shaft flexible, so the studies of wind turbine sub-synchronous oscillations based on rigid shaft model are not reasonable, this paper introduces a new flexible shaft model for studying of wind turbine sub-synchronous oscillations. Flexible equipments, such as joints and gearbox are taken into consideration when the model are set up, so this model is far more scientific.

Abstract: The random fluctuation and anti-peaking characteristics of wind power has brought new problems for the power system optimal dispatch. Based on the interaction characteristic of the load, this paper played the utility of interactive load which can help system consumers the positive and negative fluctuations of wind power, and considered interactive load as a scheduling resource into the traditional day-ahead scheduling model. Taking into account the effects of interactive load on system operating costs and power flow distribution, this paper established a generation scheduling model which the aim are both the system operating costs and network loss minimization in large-capacity wind power integrated system, and reformulated the multi-objective optimization problem into a single objective nonlinear programming problem by means of the fuzzy theory, and made the generation side and the demand side of the power grid can participate optimal allocation of resources, and provided a new ideas and methods for achieving source and load interactive in smart grid environment. The simulation on IEEE 30-bus system indicated this method can reduce system operating costs and network losses effectively, and improve wind power consumptive level as well as too.

Abstract: The purpose of this study is to investigate the parameters that affect the cost-effectiveness of wind farm land use and wind energy harvesting efficiency. The research team applies two reverse rotating vertical-axis wind turbines (VAWTs) to explore how wind speed and various distances of wind turbines affect the operation efficiency of a prospective wind farm. A data acquisition system has been constructed to record the wind speed along with a variety of wind turbine output data in a wind tunnel test in order to identify the layout that help to achieve the best wind harvesting efficiency. The layout is then applied in the field test for further observation and data collection. The experiment results show 1) when two VAWTs are moved toward each other (from 300 cm to 180 cm), both turbines observe performance gain, and 2) when two VAWTs are set at a distance of 1.5 to 2.0 times the turbine diameter, the performance of both units increases by about 11% over the efficiency obtainable by their stand-alone counterpart.

Abstract: Wind turbine system (WTS) is a representative distributed power generation (DG). Establishment of WTS model and control strategies is of important practical significance. One critical field is the research of inverter system. It should be operated in stand-alone (SA) or grid-connected (GC) mode. The purpose of this thesis is to establish simulation platform of WTS inverter control model in Matlab/Simulink environment, which includes two typical DG control strategies, PQ and V/f. The wind fluctuation makes inverter output power harder to follow wind turbine (WT) power. In GC mode, PQ strategy was adopted to balance inverter output power and WT generated power. In SA mode, V/f strategy was applied to keep emergency load voltage stable. The bidirectional smooth transitions between SA and GC mode were well accomplished. Simulation proves the model can survive grid failures or load shedding. The study can be used in research of DG operation control.

Abstract: The development of wind power is growing rapidly in recent years. At the same time, the environment problem has been increasingly prominent, especially the haze. Through the analysis of large numbers of data, it is not hard to find the formation of haze is almost synchronous with the development of wind power. Whether there being some inevitable connection, is the focus of this research. In this paper, through theoretical analysis and practice analysis, it shows that the distribution of wind power plants can reduce its downstream wind speed. And this paper puts forward some new recommendations for the future planning and construction of wind power.

Abstract: This work focuses on the probability distribution function of wind power variation. After analyzing the characters of the power fluctuation data, normal distribution function, t location-scale distribution function and mixed second-order one-dimensional Gaussian distribution function are chosen to describe the wind power variation. Then K-S test(Kolmogorov-Smirnov) test and Pearson product-moment correlation coefficient are used to evaluate the fitting effect of the three distribution functions respectively, which indicates that the mixed second-order one-dimensional Gaussian distribution is the most appropriate one. At last, the factors affecting the parameters of Gaussian mixture distribution and to what degree they can achieve are investigated.

Abstract: To improve the using efficiency of clean energy, in this investigation, three wind-heating devices, nonlayered-stirring heating device, layered-stirring heating device and layered extruded stirring heating device, were designed, fabricated and tested. The performance of these three devices was investigated experimentally. Results show that, under the experimental conditions, the layered extruded stirring heating device is the most efficient, and its heating efficiency reaches 46.4%. Then, the computational fluid dynamics (CFD) models were established base on these three devices. The comparative analysis of the simulation and experimental results, both obtained consistent heating law. This suggests that the use of the software CFD simulating the stirring heating device is feasible.

Abstract: The Aerodynamic Performance of 2D Savonius Rotor in Ground Effect is Numerically Simulated through Solving Unsteady Compressible RANS Equations and the Standard k-ε Turbulence Model. the Calculation Results Indicate that the Ground Effect Influences the Starting Performance and the Power Output. the Optimal Height between the Ground to the Lowest Part of the Rotor is 0.4 Times Rotation Diameter, at which the Starting Performance is Optimal. the Ground Effect also Increases the Power Coefficient and the Tip Speed Ratio Corresponding to the Maximum Power Coefficient. when Determining the Rated Tip Speed Ratio, the Fluctuation of the Torque Values and the Power Coefficient with Different Tip Speed Ratio should be Synthesized.