Advanced Materials Research Vols. 608-609

Abstract: Effects of tip losses, hub losses, amended attack angle, and amended thrust coefficient are taken into consideration to analyze aerodynamic performance of wind turbine blades based on the blade element momentum (BEM) theory. Based on amended calculation of BEM theory, a program code is developed by software named Matlab. Using a 1500kW wind turbine as an example, aerodynamic information, performance coefficients and blade load distributions are calculated. Compared with the well-known international wind power design software called Garrad Hassan (GH) Bladed, the results have good consistency, which further verifies amendments to the model algorithms and accuracy of the calculation. As a result, the amended calculation of BEM theory can reflect blade aerodynamic performance characteristics under actual operating condition, which has good reference and practicality for the wind turbine design and evaluation.

Abstract: As the increasing of the wind power capability， in order to ensure the stability of the grid while the voltage dips， the LVRT ability of the wind power turbine has become necessary. Realizing LVRT， is not only the question the built and will build wind power system are facing, but also the challenge of the will build and operating ones. Actually, many connected operating wind power system can’t meet the LVRT, this is why the large scale wind power off-grid events happened frequently, so the reformation of the wind power system LVRT is an emergency question to be solved. This paper introduced the main methods for LVRT reformation, based on this, some LVRT reform equipment was summarized for the wind turbine; and further, some reform methods were introduced for wind farm.

Abstract: Aiming at the phenomenon that the doubly fed induction generator (DFIG) can supply active power and absorb reactive power in the range of normal operation involves stability and transient, this paper proposes a novel method based on the fuzzy self-adaption PI control to control TCR to compensate the reactive power of wind farms required, and to improve the stability of voltage in wind farms. In this research, the wind generator model of being regarded as reactive load is established in Simulink of MATLAB. The results show that: the voltage and current distortion of the wind generator can be restrained well by using the SVC system proposed in this paper, and the stability of voltage and current in wind farms can be improved effectively.

Abstract: Renewable energy resources such as wind, wave, solar and biomass are becoming more important, and Wind-PV-ES hybrid power system is a promising and efficient utilization of renewable energy. Based on the sequential Monte-Carlo simulation approach, an evaluation model of Wind-PV-ES hybrid generation system is built, and storage time series model is optimized. Lastly, the effectiveness and feasibility of the proposed model is verified by a practical example, and the system impacts of PV penetration level, energy storage capacity and rated output power are illustrated.

Abstract: This paper carried out a study on the contribution of wind farm to power balance of power system by wind power output control. The study mainly focuses on active power control capability of double feed induction generator (DFIG) based wind turbine, active power control mode of wind farm and capability of wind farm to participating in peak-load regulation. According to the National standard of China GB/T 19963-2011, a study case is given to simulate the impact of wind farm grid integration based on a real power system in order to validate the active power mode and control process presented in the paper.

Abstract: Downburst is a kind of strong wind that resulted from the flow downdraft in thunderstorm, which could assert the most serious destruction in the zone nearby ground. Researches on downburst usually focusing on modeling and calculations of downburst wind profiles while the proposed nondimensional empirical models are dispersed for practical engineering applications. Accounting for this problem, diagram for of downburst wind profile calculation is cleared up by assuming jet impinging orthogonally and axisymmetrically to plane ground. Different empirical models, which include maximum horizontal velocity distributions at different radial locations, height distribution of half maximum horizontal velocity along radial direction, and horizontal velocity distributions at different heights with constant radial location, are presented and combined together to calculate dimensional radial wind profiles of horizontal velocity. The obtained wind profiles can be combined with atmosphere boundary layer wind profiles together for practical engineering applications.

Abstract: In order to realize remote measure, remote communication and remote control function in wind-solar hybrid street light operation management system, a kind of management system based on ZigBee technology is introduced by this paper. This design is used JN513x series ZigBee wireless communication micro controller to build hardware platform, and is used Modbus protocol to manage all light controllers. The data exchange between each wireless module and the gathering terminal is completed by ZigBee wireless network. The data exchange between each gathering terminal and monitoring center is completed by GPRS/CDMA network. This design has applied to Hunan new energy road lighting project with stability and excellent performance.

Abstract: The power fluctuation of wind turbine often causes serious problems in electricity grids. Therefore, short term prediction of wind speed and power as to eliminate the uncertainty determined crucially the development of wind energy. Compared with physical methods, support vector machine (SVM) as an intelligent artificial method is more general and shows better nonlinear modeling capacity. A model which combined fuzzy information granulation with SVM method was developed and implemented in short term future trend prediction of wind speed and power. The data, including the daily wind speed and power, from a wind farm in northern China were used to evaluate the proposed method. The prediction results show that the proposed model performs better and more stable than the standard SVM model when apply them into the same data set.

Abstract: This article describes the wind source heat pump system. The heat energy gained by the wind turbine as a heat pump heat source. Use of a 300kw wind turbine induced heat. In order to calculate wind-induced heat efficiency, collected the data of wind speed and direction within a year. Using the WAsP software simulated the wind power density. Output power from wind turbine is 71kw. If using wind turbine to power generation,can only get 35.7kw. Compared the efficiency of wind-induced heat and wind power generation,obtained wind-induced heat enhanced the wind energy utilization.

Abstract: Cylindrical uranium dioxide pellets, which are the main components for nuclear fuel elements in Light Water Reactor, should have a high density profile, uniform shape and quality for the safety used as a reactor fuel component. The quality of green pellets is conventionally monitored through a laboratory measurement of the physical pellets characteristics followed by a graphical chart classification technique. However, this conventional classification method shows some drawbacks, such as the difficulties on its usage, low accuracy and time consuming, and does not have the ability to adress the non-linearity and the complexity of the relationship between the pellet’s quality variables and the pellett’s quality. In this paper, an Improved Levenberg-Marquard based neural networks is used to classify the quality process of the green pellets. Robustness of this learning algorithm is evaluated by comparing its recognition rate to that of the conventional Back Propagation neural learning algorithm. Results show that the Improved Levenberg-Marquard algorithm outperformed the Back Propagation learning algorthm for various percentage of training/testing paradigm, showing that this system could be applied effectively for classification of pellet quality.