wind power in sungai besi camp

8/2/2019 Wind Power in Sungai Besi Camp

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CHAPTER 1

INTRODUCTION

1.1 Introduction

In the recent year, renewable energy applications are rapidly increasing in power

generation systems. Wind is one of the fastest growing energy resource and their

penetration levels in power system are increasing worldwide. The benefit of wind power

generation is in providing clean energy and saving fossil fuels thereby reducing

emissions. Energy generation by wind power plants is without fuel cost but nature

dependent.

The meteorological factors like wind speed and air density greatly influence the

wind power generation. Of these variables, the wind speed has a major influence on

wind turbine power output since the power output varies with cubic value of wind speed

[8]. The air density variation during different period of a year and at different location is

lesser compared to the wind speed variation. In planning a wind power generation in


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Kem Sungai Besi, the first thing is to get wind speed at several locations especially at

high locations in Kem Sungai Besi. Turbo meter wind speed indicator was used to get

the wind speed.

As is well known, the term wind power describes the process by which the wind

is used to generate mechanical power or electricity. Wind turbines convert the kinetic

energy in the wind into mechanical power. Simply stated, a wind turbine works the

opposite of fan. Instead of using electricity to make wind, like a fan, wind turbines use

wind to make electricity. The wind turns the blades, which spin a shaft, which connects

to a generator and makes electricity.

Figure 1.1 Wind turbine diagram


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1.2 Objectives

The main objective of this project is to determine and design a suitable wind turbine

which could be employed for small scale applications in Kem Sungai Besi using

Computer-Aided Design (CAD). The other objective is to analyze the critical static

stresses of the design on the components and structures using Computer-Aided Analysis

(CAA).

1.3 Problem Statement

In determine and design of the wind power generation, wind resources is very important.

Since in Kem Sungai Besi average wind speed is low, this project will be focus on

designing wind turbine that have features suitable in low speed wind and work in this

situation.

1.4 Scopes of Work

The scopes of this project as shown below:

FYP 1

a. Literature study on the function of the main mechanical, structural, control andelectrical components of wind turbine.

b. Understand a basic knowledge of the construction and operation of the windturbine for electricity production.


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c. Conceptual design.FYP 2

d. Determination size of each components and structures by analytical analysis.e. Using the Computer-Aided Design, produce a good design of the wind turbine.f. Using the Computer-Aided Analysis, the maximum static stresses on the wind

turbine components and structures.


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CHAPTER 2

LITERATURE REVIEW

This chapter includes the study of wind in Kem Sungai Besi, the history of wind turbine,

advantages and disadvantages of wind turbine, types of wind turbine, basic knowledge

of the structures and the components of wind turbine.

2.1 Analysis of Wind Speed in Kem Sungai Besi

Speed of wind at a location is varying randomly with time. Hence, the speed of the wind

at a site should be properly analyzed and understood. Analyzing the speed of wind is

important to design a steady structures and it components of wind turbine with refer to

the wind characteristics at the site.

Wind exists because solar radiation reaches the Earths highly varied surface

unevenly, creating temperature, density and pressure differences which cause the air to

move. The different of heat across the earth will be helping creating the wind. In

explanation, the air is hot in warmer regions of the earth and therefore it is in a high

pressure, compared with in colder regions where the air is at a low pressure [10]. The


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movement of air from area of high pressure to low pressure is called wind as shown in

Figure 2.1.

Figure 2.1 How wind is created

Wind speeds in Kem Sungai Besi is depends on the location which is wind

speeds is varying. The weekly wind speeds at some locations in Kem Sungai Besi are

shown in Table 2.1. Turbo Meter Wind Speed Indicator is used to obtain wind speed.


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Table 2.1 Weekly wind speeds in m/s

Location

September October November

3 4 1 2 3 4 1 2 3 4

Abseiling

tower UPNM 2.0 2.1 1.8 1.8 1.9 2.1 1.9 1.6 1.8 1.6

Iron hill 2.6 2.4 2.1 2.6 2.6 3.0 2.4 2.8 2.7 2.9

Sri Kinabalu

hill 1.9 1.8 1.2 1.3 0.9 1.3 1.1 1.3 1.1 1.3

Refer to the table 2.1, the wind speeds at 3 locations in Kem Sungai Besi is not

consistent. The average wind speed at Abseiling tower UPNM is 1.86 m/s. Then, the

average wind speed at Iron Hill is 2.61 m/s. Lastly,the average wind speed at Sri

Kinabalu Hill is 1.32 m/s.

2.2 Wind Turbine History

Wind turbine is a rotation machine which converts the kinetic energy in wind into

mechanical energy. The era of wind turbine began close to 1990. The first modern wind

turbine was constructed in Denmark in 1890. The function is as supplier electricity to the

rural areas. After a few years, a large wind electric generator was built in Cleveland,


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Ohio. At that time, the first speed-up gear box was introduced in the wind turbine design

[9].

At 1950, the researcher gets to improve the behavior of wind turbines with using

the high tip speed ratio and low solidity concept. For an example of improving the

behavior of wind turbine is the lightweight constant speed rotors were developed in

Germany which the fiber glass blades attached to the simple hollow towers supported by

guy ropes. The rated output was achieved at 100 kW with using 15 m diameter of swept

area [9].

In 1973, the oil crisis had occurred and forced the scientist and engineer to

thought the solution without depends on the fossil fuel. They are realized that the cost of

fossil fuels will be increase year by year. Furthermore, the fossil fuel from the plants

would be vanished one day. Moreover, for the safety reasons, the nuclear power was

unacceptable. These factors caused the revival of interest in wind energy. United States

believe, depend on National Aeronautics and Space Administration (NASA) in

development of the new model with more performance on the wind turbines will get

profit and advantage. As a result, the series of horizontal axis wind turbines named

MOD-0, MOD-1, MOD-2 and MOD-5 were developed in the better performance and

high efficiency [3]. During the same time, scientists at Sandia Laboratories were focused

on their research. Then, the Darrieus wind turbine was developed. At 1980, several

models of the Darrieus machine in different sizes were fabricate for the good

performance [3].


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Figure 2.2 The MOD wind turbine [3]

2.3 Advantages and Disadvantages of Wind Turbine

Like every form of power generation, wind turbine offers several advantages. The

advantages of the wind turbine are:

a. Wind turbine does not generate pollution or radioactive waste.b. Provide electricity to individual homes or other facilities on a self reliant basis,

with no need for fuel or other materials to be supplied.

c. Wind turbine is cost effective and reliable.d. Does not consume any non-renewable resources.e. The wind is free.f. Available in a range of sizes.

The disadvantages of the wind turbine are:

a. The strength of the wind is not constant.


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b. The wind turbine can be damaged in thunderstorms.c. The blades of wind turbine can hit birds who attempt to fly between them.d. Some people consider the turbine to have an undesirable appearance.e. Use of wind turbine in poor locations is not effective and does not produce

significant energy.

f. The power output of wind turbine remains restricted by their design.

2.4 Type of Wind Turbine

The use of wind turbine to harness the energy in the wind is not a new concept and can

be dated back as far back as the Chinese in 2000 B.C. A number of different types of

wind turbine exist today. They are classified into horizontal axis and vertical axis wind

turbines based on their axis rotation.

2.4.1 Horizontal Axis Wind Turbines

The Horizontal axis wind turbines (HAWT), has a rotor which move

perpendicular to wind direction. Blades are mounted radially from the rotor and

used to create a lift/drag differential which causes the rotor to rotate. The high

speed two bladed HAWT can have efficiencies as high as 47% power extraction

from the wind. They are generally grid connected for commercial use in

electricity generation but smaller versions have been fabricated and sold

commercially for small scale applications.


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The advantages of the HAWT are that it can obtain a relatively high

efficiency and that because they are typically tower mounted they have to access

to the higher undisturbed wind flows above the ground level. With this

advantages of being tower mounted there is also a trade off. There is an increased

capital cost incurred in the need for the tower and also the rotor and generator are

more difficult to attend to for maintenance and repair than if the wind turbine

was mounted on the ground. There is also a general need to orientate them into

the wind by means of a tail or yaw mechanism. The final major disadvantage of

this type of wind turbine is that there is a need for over speed protection as they

can rotate at velocities several times that of the wind speed. Figure 2.3 show the

HAWT.

Figure 2.3 A horizontal axis wind turbine


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2.4.2 Vertical Axis Wind Turbines

The vertical axis wind turbine (VAWT) as seen at Figure 2.4, has rotors which

move in the direction of the wind. A Darrieus VAWT, named after the French

inventor George Darrieus. The rotor surfaces rotate around a vertical axis. The

aerodynamics of the rotors creates a pressure differential and induces rotation

around the vertical axis. VAWTs can obtain efficiencies of up to 37% of the

power obtainable from the wind. Early designs were used primarily for pumping

water as the efficiencies were low but a good low-end torque was obtainable.

With increased research into the vertical axis wind turbines a number of different

designs were fabricated and patented.

One of the advantages of the VAWT is that it doesnt have to be

orientated into the wind. There is no requirement for a tower therefore there are

lower capitals costs and also the fact that the generator is mounted at ground

level means that it is easy to access. No over speed protection is generally needed

as this type of turbine rotates at speed less than that of the wind. Because they are

not tower mounted they dont have to access at higher wind speeds that the

HAWTs have and they also have the disadvantage that they possess a lower

power coefficient than HAWTs. Not being able to rotate faster than the speed of

the wind often means that extensive gearing is required to match the optimal

speed of the rotor with that of the generator.


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Figure 2.4 Darrieus wind turbine [3]

2.5 Main Structure of a Wind Turbine

2.5.1 Tower

The tower carries the weight of the nacelle and the rotor blades. The tower also

absorbs the huge static loads caused by varying power of the wind. There are

three basic tower type which is lattice tower, tubular steel tower and fixed guyed

tower. Schematic views of these towers as shown in Figure 2.5.


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Figure 2.5 Different types of towers [3]

The lattice towers are fabricated with the steel bars joined together to

form the structure as shown at Fig. 2.8. They are same structure to the

transmission electric towers. Lattice towers used only half of the materials that

are required to build tubular tower [3]. This makes it lightweight and cheaper.

Lattice towers are not maintenance friendly which is maintenance of systems are

difficult as workers would be exposed to chill on the bad weather. Moreover, the

towers do not have any lock doors and it is less secure for maintenance.

Most of the recent installations are provided with tubular steel towers.

These towers are fabricated by joining tubular sections of 10 to 20 m length. The

tubular tower with it is circular cross-section can offer optimum bending

resistance in all directions [4].

Fixed guyed towerTubular towerLattice tower


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Towers for small wind systems are generally fixed guyed towers. This

means that there are guy wires anchored to the ground on three or four sides of

the tower to hold it erect. These towers cost less than lattice towers, but require

more land area to anchor the guy wires. Some of these guyed towers are erected

by tilting them up. This operation can be quickly accomplished using only a

winch, with the turbine already mounted to the tower top. This simplifies not

only installation, but maintenance as well.

2.5.2 Rotor

The portion of the wind turbine that collects energy from the wind is called the

rotor. The rotor usually consists of two or more wooden, fiberglass or metal

blades which rotate about an axis (horizontal or vertical) at a rate determined by

the wind speed and the shape of the blades. The blades are attached to the hub,

which in turn is attached to the main shaft.

Blades of wind turbine have airfoil sections. Thought it is possible to

design the rotor with a single blade because balancing of such rotors would be

real engineering challenge. Two bladed rotors also suffer on these problems of

balancing and visual acceptability. Hence, almost of commercial designs have

three bladed rotors. Size of rotor depends on the power rating of turbine. Blades

are fabricated with a variety of materials range from wood to carbon composites.

The wood and metal are usually used to create small scale units of wind turbine.


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2.5.3 Nacelle

The nacelle is the body of wind turbine. It houses the gear box, low and high

speed shafts, generator, controller and brake system. It also contains the blade

pitch control, a hydraulic system that controls the angle of the blades, and the

yaw drive, which controls the position of the turbine relative to the wind. The

nacelle is shown in Figure 2.6.

Figure 2.6 Nacelle of a wind turbine [2]

2.6 Components of a Wind Turbine

Components of a wind turbine usually sit over the tower. The main components of a

wind turbine for electricity generation are the break, the transmission system, the

generator, the yaw and control system. Their layout is shown at Figure 2.7.


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Figure 2.7 Cross-section of nacelle in a wind turbine [2]

2.6.1 Transmission System

Transmission increases the rotation of the generator to the speeds necessary for

efficient electricity production. Some DC-type wind turbines do not use

transmissions. Instead, they have a direct link between the rotor and generator.

These are known as direct drive systems. Without a transmission, wind turbine

complexity and maintenance requirements are reduced, but a much larger

generator is required to deliver the same power output as the AC-type wind

turbines. [2].


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2.6.2 Generator

The generator is what converts the turning motion of a wind turbines blades into

electricity. Inside this component, coils of wire are rotated in a magnetic field to

produce electricity. Different generator designs produce either alternating current

(AC) or direct current (DC), and they are available in a large range of output

power ratings. The generator's rating, or size, is dependent on the length of the

wind turbines blades because more energy is captured by longer blades. [2].

2.6.3 Braking System

Wind turbine must have two independent braking systems which is aerodynamic

and mechanical braking. Aerodynamic braking system is usually spring operated,

in order to work even in case of electrical power failure, and they are

automatically activated if the hydraulic system in the turbine loses pressure. The

hydraulic system in the turbine is used turn the blades or blade tips back in place

once the dangerous situation is over.

The mechanical brake is used as a backup system for the aerodynamic

braking system, and as a parking brake, once the turbine is stopped in the case of

a stall controlled turbine. [1].


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2.6.4 Yaw System

A wind turbine has a yaw system as seen at Figure 2.8 that turns the nacelle

according to the actual wind direction using a rotary actuator engaging on a gear

ring at the top of the tower. The wind direction must be perpendicular to the

swept rotor area during normal operation of the turbine. A slow closed loop

control system is used to control the yaw drives [2]. A wind vane usually

mounted on the top of nacelle that senses the relative wind direction. In the same

time, the wind turbine controller can get the signal and then operates the yaw

drives.

In some designs the nacelle is yawed to reduce power in high winds and

in extreme conditions the machine can be stopped with nacelle turned the rotor

axis at the right angles to the wind direction [2]. Although simple, the yaw

system has proved one of the more difficult parts of the turbine to design.

Prediction of yaw loads remains uncertain especially in turbulent wind condition.

Figure 2.8 Yaw system of a wind turbine


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2.7 Review of Computer Software

Computer software is very important whether in design or problem solving. Computer

software can help reduce cost and saves time. In engineering, software that commonly

used are computer-aided design software (CAD) and computer-aided analysis software

(CAE).

2.7.1 Computer-Aided Design (CAD) Software

CAD is a process of design and design-documentation that use computer

technology. CAD is used in various applications, including automotive,

shipbuilding and aerospace industries, industrial and architectural design, and

many more.

For the design of wind turbine, software called SolidWorks is decided to

be used for the design process. SolidWorks software is three dimensions

mechanical CAD software that are provides tools for mechanical design. The

advantages of using SolidWorks are user friendly, easy to understand, low cost

and the formats is transferable to any CAE software for analysis process.

2.7.2 Computer-Aided Analysis (CAA) Software

CAA software is the broad use of computer software to aid in engineering tasks.

To get an excellent design results, analysis should be done on the design material

to study the performance of the design. For analyzing of the wind turbine, several


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software is decided to be used in analyzing the components and structure which

are:

(a) MSC NastranMSC Nastran is used for Finite Element Analysis (FEA) of simple

or structure. It can be used multiple CAA studies including multi physics

analysis. In addition, MSC Nastran offers a complete set of nonlinear

analysis capabilities in both implicit and explicit solution technology,

thermal and exterior acoustics and also the coupling analysis between

various disciplines such as thermal structural and fluid structure

interaction.

(b) MSC Patran

MSC Patran is similar software of MSC Nastran which used as

pre-processing software for Finite Element Analysis (FEA), providing

solid modeling, meshing, and analysis setup for MSC Nastran.


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CHAPTER 3

METHODOLOGY

3.1 Introduction

The methodology is generally a guideline method used to achieve the objective of this

project. Method is used to complete the project which is divided into three stages,

namely literature review, the design process and design analysis. During the design

process, several design concepts are required to choose the best and appropriate design

concepts. For design analysis, there are two methods used in the analytical study and

computer simulation. The methodology is early design process to perform the study.

3.1.1 Methodology Flow Chart

During design process, a methodology flow chart is done as a guideline and the

work will been done according to the methodology flow chart. The methodology

flow chart shows the step project process on how the project will be carried out

until the completion of the project. The methodology flow chart of this project is

shown in Fig. 3.1.


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Figure 3.1 Methodology flow chart

Identify Project Title

Problem Understanding

Literature Review

Design Process

Analysis of Design

Results

Computer AnalysisAnalytical Analysis

Conclusion


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3.2 Conceptual Design

The conceptual design aimed to select the most suitable topology for wind turbine from

the endless combinations of design choices. The most important design choices related

to wind turbine topology as follows:

1. Rotor axis orientation: HAWT or VAWT.

2. Rotor Position: Upwind or downwind of tower.

3. Rotor Blades: Number of blades.

4. Power Control: Variable pitch or yaw control.

5. Tower Structure: Tilt-up, fixed or free standing.

3.2.1 Rotor Axis Orientation

A basic assessment of strengths and weaknesses was used to assess suitability of

both HAWT and VAWT configurations.

VAWT configurations:

Advantages:

1. Generator, gearbox etc may be placed on the ground so a tower may be

avoided.

2. Easier to maintain since the drive train components are near the ground.

3. Easier installation if a tower is not used.


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4. Yaw mechanism is not required.

5. Efficiency loss from the yaw device tracking the wind is negated.

Disadvantages:

1. The VAWTs lack of a tower eliminates most of the additional energy available

higher up due to wind shear.

2. Overall efficiency is low.

3. The highly cyclic power and thrust generated by VAWT rotors result in higher

fatigue loads.

4. High thrust loads on bottom bearing due to rotor weight.

5. Bearing replacement requires full strip down of machine.

HAWT configurations:

Advantages:

1. Blades are to the side of the wind turbine centre of gravity, helping stability.

2. Ability to pitch the blades in a storm to minimize damage.

3. Usually self-starting.

4. Can be set up in forests above the tree-line.

5. Tall towers improve access to stronger winds.

Disadvantages:

1. Transportation of tall towers can be difficult.

2. Environmental impacts associated with tall towers.

3. HAWTs have difficulty operating near the ground where the wind flow is

more turbulent.


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Conclusion: The HAWT configuration was found to be considerably more

suitable and was the chosen configuration, mainly to efficiency advantages.

VAWT appear to have found a niche in urban environments where the wind

resource is more turbulent, and roof-top mounting is available offering

considerable height gains without the use of a tower. The power generation for

rural areas and small scale uses appears to be firmly in the HAWT.

3.2.2 Rotor Position

The rotor position is relevant to only the HAWT configuration and has major

consequences on virtually all drive train component design requirements.

Upwind configurations: Upwind machines have the rotor facing the wind. This

configuration is by far the most common position for HAWTs.

Advantages:

1. Tower shadow effect is much less, reducing dynamic rotor blade loading,

noise and power reduction.

2. Lower blade fatigue.

Disadvantages:

1. Accurate predictions of blade deflections in turbulent wind are required to

prevent the rotor blades from striking the tower.

2. Tilting rotor blades back to prevent tower strike reduces power output slightly.


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3. Requires load inducing mechanical yaw mechanism to keep the rotor facing

the wind.

4. May require an extended nacelle to position the rotor far enough away from

the tower to prevent tower strike.

Downwind Configuration: Downwind machines have the rotor on the lee side of

the tower.

Advantages:

1. Allows the use of very flexible blades without the risk or tower striking.

2. Flexible blades may reduce weight.

3. Flexible blades can be less expensive to make.

4. May be built without a yaw mechanism, if the nacelle is designed to follow the

wind passively.

5. Flexible blades may take some loading off the tower in high winds due to the

blade bending absorbing some of the wind energy.

Disadvantages:

1. Blades are subject to large negative impulse loads each time they pass the

tower, contributing to fatigue damage and a thump noise effect.

2. Fatigue and structural failure due to turbulence.

Conclusion: The downwind comparison featured slightly better reliability and

maintainability because of the absence of the yawing mechanism; however the


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environmental drawbacks due to increased noise made the upwind configuration

marginally more attractive.

3.2.3 Rotor Blades

The power coefficient increases as the number of blades increase.

Three Blades : Three bladed rotors were found to be the accepted industry

standard and tend to be the standard against which all other concepts are

evaluated.

Advantages:

1. Lower impulsive noise from tower shadow than two or one blades.

2. Three per revolution noise is less annoying than one or two per revolution.

3. More dynamically balanced rotor due to 120 degree spacing of blades.

4. Three percent more aerodynamically efficient than two blades.

Disadvantages:

1. Cost associated with extra blades.

Two Blades : Two bladed rotors are slightly less efficient than three bladed

rotors and generally need to be mounted on a teeter hinge to combat the

aerodynamic imbalances to the turbine when a rotor blade passes the tower.

Teetering hubs are considerably more complex than the fixed hubs generally

found on three bladed rotors.


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Advantages:

1. Cost and weight saving over three blades.

2. Six percent more aerodynamically efficient than one blade.

3. Improved blade, drive train, tower, nacelle & yaw bearing load relief due to

teetering mechanism.

Disadvantages:

1. Increased rotor noise due to higher tip speed.

2. Requires up to fifty percent increased rotor radius to achieve roughly the same

power output as a three bladed rotor.

3. Require higher rotational speeds to yield the same energy output as three

blades.

One blade: One-bladed rotors do exist but are not widespread, they generally

experience all the same problems experienced with a two bladed rotor but to a

larger extent.

Advantages:

1. Cost & weight saving over two and three blades.

Disadvantages:

1. Increased rotor noise due to higher tip speed.

2. Require higher rotational speeds to yield the same energy output as two

blades.

3. Requires a counterweight to balance the rotor.


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Conclusion: The three blades rotor design was chosen on the grounds of its

superior environmental performance and the potential for a simpler design,

negating the need for a complex teetering hub. The cost saving potential for one

and two-blade configurations were not expected to be realised due to the

requirement for larger blades, teetering hubs and counterweight.

3.2.4 Power Control

Various control methods were found to be available to either optimise or limit

power output, required so that the wind turbine achieves maximum advantage

from the wind and reaches its maximum or rated power at the desired wind

speed. Speed control is required to put a ceiling on the rotational speed and

output power as the wind speed increases, to serve as a protection mechanism

preventing the rotor blades from rotating too fast and possibly breaking. Active

control systems depend on transducers to sense conditions and motors to drive

the control actuation, adding complexity and cost to the wind turbine design. For

this wind turbine design the control must be simple and passive (use natural

forces for actuation) to minimize complexity and cost. The mainstream control

options are summarized here:

Pitch Control : The purpose of pitch control is to optimise the blade angle to

achieve certain rotor speeds or power output. This can be to achieve maximum

advantage from the wind, and also for overspeed protection in high wind.


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Advantages:

Control can be achieved passively.

2. Increased energy capture.

3. Provides aerodynamic braking.

4. Reduced extreme loads on the turbine when shut down.

5. Very effective way to limit output power by changing aerodynamic force on

the blade at high wind speeds.

6. Can still generate power in extreme wind speeds.

Disadvantages:

1. Large power swings likely to occur due to reaction times.

2. Complicated hub arrangement including pitch actuation devices.

3. Sometimes powered by hydraulic or electric motors.

Yaw Control : The yaw control ensures that the turbine rotor is constantly facing

into the wind to achieve maximum effective rotor area resulting in maximum

power output.

Advantages:

Control can be achieved passively.

2. Fairly simple arrangements are possible.

3. Rigid hub can be used with no variable pitch mechanism.

Disadvantages:


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Requires a robust yaw system.

2. Large moments of inertia about nacelle and yaw axis.

3. Slower reaction than other control methods.

4. Only really practical for variable speed machines.

Conclusion : Pitch control and yaw control were assessed as being equally

suitable for this application. They both offer minimal negative noise related

environmental impact which was a major deciding factor. Both were deemed to

be relatively inexpensive to design and manufacture as bearing arrangements and

mechanisms were expected to be uncomplicated for this wind turbine.

3.2.5 Tower Structure

The function of the tower is to elevate the wind turbine above the low wind

speeds experienced at the base of the vertical wind profile, and above

obstructions such as buildings, trees & hills. The tower must support the weight

of the wind turbine and also handle the thrust loads put on it by the wind. Three

basic tower types were found to be used in wind turbine installations and are

summarized below:

Tilt-up tower : Usually tilt-up towers are tubular steel construction with sections

of pipe coupled together, and 4 sets of guy wires attached at each joint. They

consist of the tower pole and a gin pole that is attached to it at 90 degrees.


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When the tower is down the gin pole sticks up in the air at 90 degrees and is used

as a lever to lift or lower the tower, pivoting on a sturdy base.

Advantages:

1. Inexpensive.

2. No crane required for installation.

3. Easy maintenance with no climbing.

4. Heights of up to 40 m are achievable for wind turbine.

Disadvantages:

1. Large footprint required (a 10 m high tower requires a diamond area 15 m x 10

m).

2. The footprint area needs to be clear and reasonably level.

3. Minor repairs are potentially more difficult due to the requirement to lower the

entire tower rather than simply climbing the tower.

Fixed, guyed tower : These towers are lifted up once, do not tilt down and are

held up by guy wires. Installation is possible without a crane by using temporary

gin poles however using a conventional crane is the usual method.

Advantages:

1. Inexpensive.

2. The footprint area does not need to be as clear and level as tilt-up towers.

Disadvantages:


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1. Maintenance on the turbine or tower is difficult and requires climbing the

tower.

2. Medium sized footprint is required (a 10 m high tower requires a 10 m

diameter footprint).

3. Requires a crane to install.

Free-standing tower : These towers have no guy wires but rely on the concrete

foundation and the steel or other material tower to hold them up.

Advantages:

1. Small footprint required.

2. Requires very little cleared space.

3. Most aesthetically pleasing option.

4. Enhanced reliability due to elimination of damage to guy wires.

5. More adaptable to composite structural material construction.

Disadvantages:

1. Maintenance on the turbine or tower is difficult and requires climbing the

tower.

2. Requires crane to install and other equipment to construct concrete foundation.

3. Foundation may require independent civil engineering design.

4. Expensive, at least a third to half higher cost than tilt-up or guyed towers.

Conclusion: The tilt-up configuration was considerably more suitable and was

the chosen configuration.


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3.3 Summary

The overall topology of the wind turbine design was selected to best suit the application

as follows :

1. Rotor axis orientation is HAWT.

2. Rotor position is upwind.

3. Rotor is three bladed.

4. Power control is pitch control and yaw control.

5. Tower structure is tilt up.

This information was sufficient to begin detailed component design and selection in the

next chapter.


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wind power in sungai besi camp

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