This paper presents modeling and analysis of horizontal and vertical wind shear effects using a wind turbine emulator (WTE) with a comprehensive model. These periodic effects generate power fluctuations and mechanical stress on the wind turbine (WT) components during its operation. The frequency of these fluctuations associates with the rotation speed and the number of blades, whereas the amplitude increases in larger turbines. Although the vertical wind shear effect was modeled in literature using WTEs, the simplified aerodynamic and mechanical models were considered for WTs. In this paper, in addition to the vertical wind shear, the horizontal wind shear is modeled in simulation and experiment using a WTE, which may have more severe effects. The utilized WTE employs a comprehensive model for the WT, which considers aerodynamic, mechanical, and electrical aspects. The interaction of different aspects and mechanical dynamics is included in the WTE, which utilizes AeroDyn and FAST software tools to model the aerodynamic and the mechanical aspects of the WT. A coupled induction motor-induction generator set was employed to develop the WTE, which is used to model the wind shear effects for a fixed-speed WT.

Investigation of Horizontal and Vertical Wind Shear Effects Using a Wind Turbine Emulator

In this paper high the ice accumulated on the wind turbine blade is removed by passing hot air through the blade. The hollow tubes are embedded in the wind turbine blades. The hollow tubes may be circular on cross section or of any suitable shape. The air is heated by an electrical heating or by gas geyser. First the air is compressed with help of a compressor. Then that air is passed through the electric heater or gas heater. The hot air is then passed through the wind turbine blade. When the hot air is passed through the wind turbine blade, the ice melts and falls down. Hot air is passed through the wind turbine blade after frequent intervals of time when the environmental conditions are favorable for icing. The process of deicing is fast.

Ice extraction from wind turbine using flow of hot air through blade

This is paper presents significance of vertical wind shear. Voltage flicker that may be initiated in the output of the horizontal axis upwind wind turbine located at any given site for a given tower height and blade length. Vertical wind shear is one of the important parameters which instigate voltage flicker in wind turbine output voltage. In this paper diverse origins of flicker, places where wind shear occurs, computation of wind shear, general impacts of wind shear, impact of wind shear on wind turbine output is discussed.

Impact of vertical wind shear on wind turbine performance

In this invention the wind turbine is fixed to the tree stem. With this mechanism, the need of foundation of the wind turbine is eliminated. The invention is related to small wind turbine. The turbine location is above the top of the tree to get sufficient wind speed. The pole may be attached to the tree with the help of springs to facilitate the growth of the tree. The pole may be attached to a tree stem at four to five different locations. The energy generated may be stored in a battery kept in a house near by the tree. This may be used for temporary electrical supply for research work in the industry, forest, rural area etc.

Tree mounted wind turbine

Diverse models of voltage flicker are established by researchers. Each model has its own disadvantage. In this paper analysis of various models is done. The models consist of various wind turbine parameters like wind turbine tower height, surface roughness of the region, building height if the turbine is mounted on a building or hill height and slope of the hill on which the turbine is mounted. Sixth order model is most appropriate for wind turbine output voltage flicker.

Sixth order model of wind turbine voltage flicker considering vertical wind shear

In this paper the site survey is done for four sites in Pune India. The electrical power is predicted for each site for different tower heights of the wind turbine. Different lengths of blades of turbine are also considered for power prediction. This method involves site survey using anemometers. This method involves low cost and less manpower.

Prediction of power yield from wind turbines for hilly sites

In today's world due to fast and rapid depletion of the conventional and nonrenewable energy resources it calls upon the requirement for sources of alternative energy, clean, green, and renewability are the top priorities. Using wind power to produce electricity is a perfect fit. Because wind energy has become the least expensive source of new electric power that is also compatible with environment preservation programs many countries promote wind power technology by means of national programs and market incentives. Also it provides an effective solution for reduction of fossil fuel consumption and pollutant emissions. The wind turbines are used for the generation of wind energy, simple in construction, economical and which gives appreciable output. Wind shear is one of the major factors affecting the working of wind turbines. Vertical shear, or the change of winds with height, either enhances or diminishes the vertical draft strengths. Input parameters and output parameters vary with different turbines. Flicker voltage is one of the major parameter concerned with the wind turbine parameters. Voltage flicker are caused due to heavy loads periodically turned on and off in a weak distribution system. This paper presents the effect produced in the output voltage and flicker voltage due to vertical wind shear in conventional type of wind turbines. The objective of this paper is to introduce the assessment parameters of the wind energy production of sites and pairing between the sites and wind turbines.

Rajesh Giri

Papers

Prediction of power yield from wind turbines for hilly sites

Laboratory set up for the study of the effect of vertical shear on horizontal axis wind turbine