The Wind Energy Conversion System (WECS) includes wind turbine, generator, control system, interconnection apparatus. Wind turbines are classified into two types;
1. Horizontal Axis Wind Turbine(HAWT)
2. Vertical Axis Wind Turbine(VAWT)
Modern wind turbine used HAWT with 2 or 3 blades and operate either downward or upward configuration. The generator used for wing energy conversion system mostly of either Doubly fed Induction generator(DFIG) or PMSG type. DFIG have winding on both stationary and rotating part where both winding transfer significant power between shaft and grid. Majority of wind turbine manufacturer utilize DFIG for their WECS due to the advantage in terms of cost, weight and size. The PMSG drives achieve very high torque at low speed with less noise and require no external excitation. Multi bridge is a technology where generators, gearbox, main shaft and shaft bearing are all integrated within a common housing. The generator with multi blades concept become cheaper and more reliable than that of the standard one, but it looses its efficiency.
To achieve high efficient energy conversion on these drives, different control strategies can be implemented like Direct Torque Control(DTC), Field Oriented Control(FOT). The wind turbine electrical and mechanical part are mostly linear and modeling will be easier.
WIND TECHNOLOGIES OF FUTURE
The wind energy technological office (WETO)works with industry partner to increase the performance and reliability of next generation wind technology while lowering the cost of wind energy. Efforts have help to increase the average capacity factor from 22% for wind turbine install before1998 to an average of nearly 35% today, up from 30% in 2000. Wind energy cost have been reduced from over 55% per KWh in 1980 to an average of under 3% per KWh in the UNITED STATE today.to ensure future industry growth, wind industry technology must continue to evolve, building on earlier successes to further improve reliability, increase capacity factor, and reduced cost.
A device that converts the wind’s kinetic energy into electrical energy. They are manufactured in a wide range of VERTICAL and HORIZONTAL types. Smallest turbines are used for applications such as battery charging for auxiliary power for boats to power traffic warning signs. Array of large turbines known as wind farms, are becoming an increasingly important source of renewable energy and are used by many countries to reduce their reliance on fossil fuels. It allows you to produced 100% clean and free electricity.
NEW OFFSHORE TECHNOLOGY TO GROW WIND TURBINE
According to DOE (Department Of Energy) the united state has significant offshore wind resources. Offshore wind could provide almost twice the total electricity generation that US needed in 2015. Development of these resources is also on the rise, largely financed by the private sector. The first proposed offshore wind project in the US was THE CAPE WIND PROJECT, a 130 turbines offshore wind farm to be located in the Nantucket sound.
The most significant benefits of offshore wind are ofcourse they cleaner energy and overall improvement in environmental impact. Other benefits may depend on projects and sites, include lower cost of energy and economic benefits for the area.
• UNDERWATER NOISE AND ELECTRO MAGNETIC FIELDS
An environmental impact of great concern that come with the installation and operation of an offshore wind facility is increased noise. Installing turbines requires pile-driving, drilling and dredging, all very loud operations. In addition, the turbines will continue to generate disruptive underwater noise and vibrations once they are functioning and will emit EM waves.
• VESSEL TRAFFIC
During the exploratory stages of the project and when the turbines and the cables are being installed, heavy boat traffic is expected in a concentrated area. This is expected to decrease as a result of shipping routes being altered to avoid the turbines. A decrease in boat traffic is not the only long term benefits that wind farm may bring to marine wild life.
WIND BELT- LOW COST ENERGY PRODUCTION USING FLUTTERING WIND BELT
Wind Belt Wind Power generator is a device which works on the principle of aero elastic flutter as well as on mutual induction process between the magnet and the coil. In this device we have arrange the magnet on the ribbon which on passing wind, start fluttering on the basis of aero elastic flutter. This fluttering causes this magnet also to reciprocate between the two coils arranged one above the other having little space for magnet between them. Due to this movement of magnet between the coils due to flutter, mutual induction takes place which leads to the induction of current as well as the voltage. As the wind speed increases, the voltage produce is increased.
Aero elastic flutter
MAGNETIC PROPERTIES OF WIND BELT
The magnet used in this device are permanent magnet or rear earth magnet and has high magnetic field intensity compared to the ferrite magnet. The benefit of using this magnet is that magnetic field of these magnets never weaken and also they have high resistance towards the corrosion.
COIL PROPERTIES OF WIND BELT
The material used in the making of the coil is copper. Thus the current induced in the coil depends largely upon the grade of copper wire used. The output depends upon the copper turn as well as the total weight of the coil.
1. The magnet were of diameter 1mm, which restricted the fluttering of ribbon, so as to avoid that, we use the same magnet of smaller size. These magnets were light in weight, same magnet strength and give better result and output voltage due to its low weight and area. Overall this device is very cheap and give better output compared to the others of this range at low to medium wind velocity.
PAST AND FUTURE COST OF WIND ENERGY
• HISTORICAL TRENDS IN THE COST OF WIND ENERGY
From the 1980’s to the early 2000, average capital cost for wind energy projects decline markedly. Historical capital cost reduction were coupled with dramatic increases in the turbine performance resulting from more advanced turbine components and larger turbine. The increase in capital cost observed in most markets from 2004 and 2009 has been largely tied to increases in the price of wind turbine. Turbine price increases have been driven by turbine upscaling, increases in material prices, energy prices, labour cost, manufacturer profitability.
• RECENT AND NEAR TERM TRENDS IN THE COST OF WIND ENERGY
Since peaking in the late 2000, project capital cost have decline but still have not return to their historical lows. At the same time, however, performance improvement have continued. Modeling that applies recent capital cost and performance data from the US and DENMARK for project expected to be built in 2012-2013 suggest that the LCOE(LEVELISED COST OF ENERGY) of onshore wind energy is now at an all time low within 6 wind resource classes and particularly in low and medium wind speed areas where the most significant technology improvement have occurred.
• LONG TERM TREND IN THE COST OF WIND ENERGY
In the future, several studies suggest that LCOE of wind energy is likely to continue to fall on a global basis and within 6 wind resource classes. By focusing on the result that fall between the 20th and 80th % of scenarios, however, the range is narrowed tu roughly a 20% – 30% reduction in LCOE. Initial cost reduction range from 1%- 6% per year.
By 2030, all but 1 scenario envisions cost reduction falling below 1% per year.
• DRIVERS OF FUTURE WIND ENERGY COST REDUCTION
Possible technical drivers include reduced component loading through a combination of improved materials and enhanced real time controls capabilities and increase reliability. Cost are expected to decline in the future- similar to those observed between 2004-2009. Manufacturing improvement and innovation in logistic challenges are also expected to further reduce the cost of wind energy. Increasing competition among manufacturers put drive down the LCOE of onshore wind energy to a greater extent than otherwise envisioned.
PERMANENT MAGNET SYNCHRONOUS GENERATOR (PMSG) – For variable speed WECS
The study of WECS based on PMSG and interconnected to the electric network is describes. The effectiveness of the WECS can be greatly into improve, under grid fault, by using an appropriate control. Consequently, WECS can not only capture the maximum wind energy, however it can also maintain the frequency and amplitude of the output voltage.
Variable speed WECS are the dominant technologies in the present wind power industry for the reason that they possess several advantages, over the fixed velocity system, as the ability to obtain Maximum Power Point Tracking (MPPT) control methodology in order to extract maximum power at different wind, higher overall efficiency, power quality and it can be controlled to reduce aerodynamic noise and mechanical stress on VS-WECS by absorbing the wind power fluctuations wind turbine generators based on PMSG are becoming popular for variable speed generation system. It is connected directly to the turbine without gearbox and so it can operate at low speed. Moreover it can reduce weight, losses, cost, demand maintenance requirement and with the advance of power electronic technology, the wind farms are at present required to participate actively in electric network operation by appropriate generation control strategy. One of the ordinary faults in WCG is short circuit. Consequently due to the increase number of VS-WECS connected to the grid, instability of the system and of the grid itself can occur. The WECS model enclosed a wind turbine, PMSG,PWM rectifier in generator side, intermediate dc circuit and PWM inverter in grid side. The aim of the control (MPPT) is to maximize the extracted power with the lowest possible impact in the utility network frequency and voltage for fault condition as well as for normal working condition. Pitch control scheme for VS-WTG if suppose in order to prevent WT damage from excessive wind speed.