04-08-2012, 12:38 PM
LOW SPEED WIND TECHNOLOGY - AN EVOLUTION IN WT-DESIGN- A STUDY ON OSCILLATORY MOTION
LOW SPEED WIND TECHNOLOGY.doc (Size: 80 KB / Downloads: 51)
ABSTRACT:
There are about 80,000 villages in the country which are still to be electrified of these there are an estimated 18,000 villages in remote and difficult areas which can not be electrified by conventional grid extension. Most of these villages are in hills, forests, deserts and islands. Govt. has decided that all the remaining unelectrified villages in the country should be electrified in a time bound manner.
To produce more power the Govt. should turn their interest in the Non-conventional energy sources rather than conventional source energy plants which may die out in the future decades.
To have power to all we need extra energy plants but they exploit huge costs. Hence we have to concentrate on low costplants. One of them is wind plant. But in India, according to the data coated by some scientists there available winds of average speed 5-10 kmph. With that low speed of wind we cannot generate required power output.
Hence we found a solution to this low velocity winds by which they can be utilized efficiently. This may be possible or not, but we are producing towards you.
Boost for non-conventional energy sources:
Energy is a major input for overall socio-economic development. Use of fossil fuels is expected to fuel the economic development process of a majority of the world population during the next two decades. However, at some time during the period 2020-2050 fossil fuels are likely to reach their maximum potential, and men price will become higher than other renewable energy options on account of increasingly constrained production and availability. The future requirements of electricity are likely to be for decentralized, people managed systems. This would call for a major transition in terms of technologies, organizations and attributes. Renewable energy is seen as an effective option for ensuring access to modern energy services in the vast country. In addition, it also provides a degree of national energy security. It has enormous potential to meet the growing energy requirements of the increasing population of the developing world, while offering sustainable solutions to the global threats of climate change. Appropriate policies and plans that optimize use of available energy sources and the selection of technologies will be necessary to lead towards a sustainable energy future.
Geographically situated in the tropical region India is endowed with abundant natural resources i.e., solar, wind and biomass which include agricultural residues which are perennial in nature. Harnessing these resources is best suited to meet the energy requirement of rural areas particularly remote and far - flung villages situated in difficult terrains where the renewable is found to be only option. Decentralized energy supply is utmost necessary to meet the minimum energy requirements of cooking, heating and lighting of rural areas which is possible through renewable energy sources where the conventional power grid is reach near future. Therefore, renewable can play a vital role in meeting the energy requirements in a decentralized manner besides feeding into the national grid to some extent.
With the increasing gap in the demand and supply of electrical power, increasing generation cost of 4-5 crores per M W, there is huge scope and need to control and conserve electrical energy in various industrial as well as commercial and other sectors. The present generating capacity is about 1,01,500 MW, there are millions of distribution transformers, aggregating to over 3,00,000 MVA capacity and it is possible to save energy of about 2,500-3,000 units annually for each 100 KVA energy efficient DT.
In the area of power generation, over 3165 MW of power generating capacity based on renewable energy sources have already been installed in the country. This constitutes over 3% of the total installed capacity in the country. The total wind power capacity of India is 1367 MW.
The improvements in technology ensure that wind power has good grid-connectivity, high power factor up to 0.99 and high plant availability above 90-95%. More ever with a unit capacity of 1-1.2 MW, these can supply power for local consumers, giving benefits of distributed generation, drastically reduced T&D looses. Increased demand for WEC’s will improve capacity utilization and bring down their cost and selling prices with economy of scale, making wind energy more competitive and economical.
INSTALLATION OF WIND TURBINE
1) Three factors determine the output from a wind energy converter they are the wind speed, the cross-section of wind swept by rotor; and the overall conversion efficiency of the rotor, transmission system and generator or pump.
2) Well designed blades will typically extract 70% of the theoretical maximum, but losses inclined in the gearbox, transmission system and generator or pump could decrease overall wind turbine efficiency to 35% or loss.
3) The kinetic energy of the wind is given by
K.E = mv3/2
By seeing the above equation we can say that any small increase in the wind speed can have a marked effect on the power in the wind.
4) Operators or users of wind turbines must ensure that there is some form of back-up to cover periods when there is insufficient wind is available.
5) For small producers, back-up can take the form of
i) Battery shortage
ii) Connection with the local electricity distribution system
iii) a stand-by generator powered by liquid or gaseous fuels.
6) When there is no grid connection, electricity that is surplus to immediately requirements must be stored on site using heavy-duty batteries. An alternative is to dump it or better, to convert it into heat that can be stored, for example as hot water in an well-insulated tank.
The basis for wind energy conversion:
The conversion of power, and hence energy, from the wind depends on creating certain forces and applying them to rotate a mechanism. There are two mechanisms for producing forces from the wind. They are
LIFT
DRAG
Lift forces are produced by changing the velocity of the air stream flowing over either side of the lifting surface. Any small change in velocity generates a pressure difference across the lifting surfaces. This pressure difference produces a force that begins to act on the high-pressure side and moves towards the low-pressure side of the lifting surface, which is, called an “AIRFOIL”. For effective operation, wind turbine blades needs to function with as much lift and as little drag as possible because drag dissipates energy.
Basic components of WECs:
Aero turbines convert energy is moving air to rotary mechanical energy. In general pitch control and yaw control exists for proper operation. A mechanical interface consisting of a step up gear and a suitable coupling transmits the rotary mechanical energy to an electrical generator.