WIND TURBINE POWER

Prepared By

Rafaqar Bhutto

• Bachelor Of Engineering

(Electronics Engineering)

• Postgraduate Diploma

(Instrumentation & Control System)

INDEX

• WIND POWER - How wind turbine works?

• Main components of turbine

1. Rotor Blades and Hub

2. Nacelle (Drive shaft, Gearbox , Generator, Yaw Motor drive, Brakes,

Anemometer and Controller)

3. Tower

4. Electrical System

• Auxiliary Plant Facilities

• SCADA (Supervisory Control And Data Acquisition)

• Advantage and Disadvantage of Wind Power Plant

• Environmental Concern

How wind turbine works

Wind turbines are used to generate electricity from the kinetic power of

the wind.

Wind turbines convert the kinetic energy in the wind into mechanical

power. This mechanical power can be used for specific tasks ( a

generator can convert this mechanical power into electricity)

The energy in the wind turns two or three propeller-like blades around a

rotor. The rotor is connected to the main shaft, which spins a generator

to create electricity.

Main components of wind turbine are shown below:

Main components of wind turbine

Rotor Blades: Converts kinetic energy of wind into rotational energy of shaft that is

connected to nacel le. As wind passes through the blades, a pressure

differential is created between the upper and lower surface of blade which

creates a lift that is perpendicular to the direction of wind.

The WTG consists of three blades madeof glass fibre-reinforced plastic; the

length of the blades is 37.5 meter.

The blades are directly bolted to the hub.

Hub The hub is fixed to the rotor shaft

which drives the generator through

a gearbox. The blades are directly bolted

to the hub and hence are controlled by

the help of motors installed inside the hub.

Nacelle:

Nacelle is a casing that holds Drive shaft, gearbox and generator, yaw

Motor drive, brakes, anemometer and controller.

The nacelle is made of fiber-rein forced plastic and designed in a way to

protect

internal components against various ambient conditions.

It also ensures adequate noise dampening.

Shaft: transfers the rotational energy of rotor into generator .

Shaft which spins a generator to create electricity

Gearbox: converts the low speed shaft of rotor to a high speed

shaft connected to generator.

Gearboxes are made up of cast steel with one planetary two

spur gear stages.

• Wind power generators convert

wind energy (mechanical energy) to

electrical energy.

• The generator is attached at one

end to the wind turbine, which

provides the mechanical energy.

• At the other end, the generator is

connected to the electrical grid.

• The generator needs to have a

cooling system to make sure there is

no overheating.

Generator:

produces electricity of medium voltage through electromagnetic induction

Yaw drive : rotates the turbine to keep it in the direction of wind for maximum output.

Yaw system

The yaw drive is an important component of the horizontal axis wind

turbines' yaw system. The yaw system comprises of geared motors and

brakes. The yaw drive is used to keep the rotor facing into the wind as the

wind direction changes.

Brakes: are used to stop the turbine in case of high wind speed to

protect the blades and power overloading. It can also be done by

changing the Pitch of blades.

Controller : monitors the entire system and controls all the operation.

Anemometry System

The main function of the anemometry system is to accurately measure and

record Wind Speed, Wind Direction, Ambient Temperature, Humidity and

other necessary information relevant to the site conditions. This information

is monitored and transmitted at the same time to many set locations. The

anemometry system comprises of two Wind Masts, Wind Mast is mounted with

a Data Logger installed at 80 meters height, equivalent to the turbine height.

These data loggers are calibrated in accordance with applicable standards;

Tower: Tower holds the entire structure at height.

The tower height of every WTG is 80 meters, equipped with internal tower

ladder along with safety harness & elevator. The tower supports the nacelle

assembly which holds the hub along with the blades.

Electrical system:

It takes the electricity from top to the bottom of the tower . The installed Wind

turbines use Asynchronous generator whose shaft is connected with a gear box

which is coupled with Hub blades. The WTG produce 690 Volts, which after

synchronization thru a frequency converter is stepped up to 22kV. It is then sent

to a substation where it is stepped up through power transformers to 132kV

Electrical Layout:

The installed Wind turbines use Asynchronous generator whose shaft is

connected with a gear box which is coupled with Hub blades. The WTG

produce 690 Volts, which after synchronization thru a frequency converter is

stepped up to 22kV through Generator, Step up transformer installed with

each turbine. Each WTG is connected with its own Ring Main Unit switchgear.

The voltage produced by each WTG is fed into system thru Ring Main unit

switchgear is interconnected with other RMUs by underground power cables

and fed into MV substation at the site.

The 22Kv is then stepped up through power transformers up to 132kV & then

power is evacuated into 132kV national Grid.

Auxiliary Plant Facilities

Earthing System

The earthing system is erected together with the foundation.

Safety for persons: The ring earthing reduces the shock hazard voltage for

persons being near the tower foundation during a lightning stroke.

Operational safety: The deep earthing guarantees a low and stable earth

resistance for the whole earthing system.

Lightning protection

The lightning and overvoltage protection for the overall system follows the

concept of lightning protection zones.

The wind turbine is equipped with a complete external and internal lightning

protection system considering a direct lightning stroke. to the ground.

Fire protection

Most components of the wind turbine generator system are predominantly

metal. This applies, for example, to the tower, the machine supports, shaft,

gear unit, hydraulic unit, brake, generator, clutch, drives, etc.

A temperature sensor is installed in the machine house and measures the

temperature inside the machine house. If a certain limit value is exceeded, a

warning message is sent automatically to the remote monitoring office and the

system is automatically shut down.

Definition

SCADA=Supervisory Control & Data Acquisition

SCADA (Supervisory Control And Data Acquisition) system refers to the

combination of telemetry and data acquisition. It consists of collecting

information from turbines, transferring it back to a central site, carrying

out necessary analysis and control, and then displaying this data on a

number of operator screens.

The SCADA system is used to monitor and control a plant or equipment.

Control may be automatic or can be initiated by operator commands.

Basics

SCADA (Supervisory Control And Data Acquisition)

The wind turbines (Wind Park) are remotely monitored and controlled (at

site) through a SCADA system . This system is called GATEWAY and can

be used for online operation monitoring, processing of user-defined reports

and statistics as well as remote monitoring of Wind Turbines. Following

data parameters can be monitored by SCADA

Main features of the SCADA system:

• Park overview

• Park control

• Turbine overview

• Turbine control

• Log viewer

• Report Generator

• Power Curve

• 24h / 10m Log

• Production Overview Log

• Weather Station Data

Park overview

The park overview of the SCADA system provides a graphical overview of

the wind park indicating the status of each individual turbine. Furthermore,

current wind and production data are shown.

Park control

The park overview makes it possible to start/stop the entire wind park,

clusters of turbines or individual wind turbines. Furthermore, the park

control can be used for setting production limits for the wind park.

Turbine overview

The turbine overview of the SCADA system gives a full overview of all

relevant parameters of the wind turbine, for instance temperatures, pitch

angle, electrical parameters, rotor speed, yaw system, etc.

Log viewer

The SCADA system features a flexible browsing of the log data of the wind

turbine. All relevant log data are accessible and can be sorted by different

parameters.

Report generator

The report generator of the SCADA system makes it possible to make all

relevant reports based on the log data. The reports can be graphically

presented to provide the best possible overview.

Advantage and Disadvantage of Wind Power Plant

The wind blows day and night, which allows windmills to produce electricity

throughout the day. (Faster during the day)

Non-Polluting Resources : Wind energy has no cost, renewable source. It

is a source of clean non-polluting.

Cost Issue : Wind cost are much more competitive with other

technologies because there is no need of fuel to purchase and minimal

operating expenses. Although wind power has decreased its cost

dramatically.

Supply and Transport Issue : It is a big issue that wind energy

cannot stored and does not always blow when electricity is needed,

but wind generated electricity can be stored ,if batteries are used , and

further good wind sites are located in remote location which is far

from that area where electricity are required.

Sound from Wind Turbines

- Increasing tip speed less sound

- The closest neighbor is usually 300 m experiences almost no noise

• Environment study revealed that power lines are a much greater

danger to birds than the wind turbines.

• Some birds even nest on cages on Wind Towers.

Environmental Concern :

Although wind power plants have little impact on the

environment as compared to fossil fuel plants ,there is some

concern over the noise produced by rotor blade and birds and

bats are also killed by flying into the rotor .