FYP Report

Control System Analysis of
Existing LIT Wind Turbine
and Anemometer Data
Logging.
By
Mr. John Paul O Brien
A project submitted in partial fulfilment requirements
For a
B.Sc. Renewable and Electrical Energy Systems
Limerick Institute of Technology
Submitted: April 2016
Supervisor: Mr. K. Moloney

LIT Wind Turbine Control System Analysis and Anemometer Data Logging
2
K00191430 REES 3 John Paul O Brien
Declaration
I declare that this report is my own work, and has not been submitted in any other form for
another award at any institution of education. Information taken from the published or
unpublished work of others has been acknowledged in the text and a list of references is given.
Signed: ____________________ Signed: _________________
(Candidate) (Supervisor)
Date: ______________________ Date: ___________________

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Dedication
I would like to thank my supervisor Mr Keith Moloney, who without he’s support the project
would not of been possible, for he’s guidance and advice on the direction of the project which
helped to keep me focused throughout the course of the project and also he’s belief and
encouragement in my ability to complete the project. He’s knowledge in renewable energy
systems also proved to be of great benefit in helping understanding the system.
I wish to thank Mr Ian Foley also who was of great help in the programming of the HMI and
he’s advice proved invaluable with regards to understanding and programming with the
Visilogic software.
I also wish to thank Dr Frances Hardiman whose advice and guidance in the formatting and
structuring of the report was of enormous benefit.
I wish to thank Nathy Brennan with who I collaborated on testing and erecting the anemometer.
I also want to thank Mr Pat Grace for demonstrating how to lower the turbine.
And finally Mr Brendan O Heney who helped with the electrical risk assessment.

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Table of Contents
Declaration.................................................................................................................................2
List of Figures.............................................................................................................................6
List of Tables..............................................................................................................................8
1 Introduction .......................................................................................................................10
2 Background.......................................................................................................................12
2.1 Components of Small Scale Wind Turbine System..................................................12
2.1.1 Rotor Blades ......................................................................................................12
2.1.2 Generators .........................................................................................................14
2.1.3 Tower .................................................................................................................15
2.1.4 Power Electronics ..............................................................................................16
2.1.5 Battery Banks.....................................................................................................16
2.1.6 Dump Load.........................................................................................................17
2.2 Application of Small Scale Wind Turbines................................................................18
2.2.1 Off-Grid...............................................................................................................18
2.2.2 On-grid ...............................................................................................................19
2.2.3 Direct Heating ....................................................................................................20
2.3 Anemometer..............................................................................................................21
2.3.1 Cup Anemometer...............................................................................................22
2.3.2 Sonic Anemometer ............................................................................................23
2.3.3 Propeller Anemometer.......................................................................................24
2.3.4 Data Logging......................................................................................................25
2.3.5 Measuring Wind Speed .....................................................................................26
2.4 Speed Control ...........................................................................................................27
2.4.1 Pitch Control.......................................................................................................28
2.4.2 Furling ................................................................................................................29
2.4.3 Active Stall Control.............................................................................................29
2.4.4 Coning................................................................................................................30
2.4.5 Electronic Torque/Stall Control..........................................................................31

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3 Safety................................................................................................................................32
3.1 Method Statement.....................................................................................................32
3.1.1 Electrical Risk Assessment................................................................................33
3.1.2 Equipment..........................................................................................................34
3.1.3 Method ...............................................................................................................35
4 Control System Analysis...................................................................................................41
4.1 Conversion Process..................................................................................................41
4.2 Speed Control ...........................................................................................................42
5 Anemometer .....................................................................................................................46
5.1 Installing Anemometer ..............................................................................................46
5.1.1 Testing Anemometer..........................................................................................47
5.1.2 Power Supplies ..................................................................................................48
5.1.3 Installing Anemometer .......................................................................................49
5.1.4 Installing Nokeval 7470 DAC .............................................................................50
5.2 Displaying Anemometer Data...................................................................................52
6 Discussion.........................................................................................................................56
6.1 Control System and Components.............................................................................56
6.2 Safety ........................................................................................................................57
6.3 Data logging ..............................................................................................................57
7 Conclusion and Recommendations .................................................................................58
8 References........................................................................................................................60
9 Appendices .......................................................................................................................64
9.1 Appendix A: ...............................................................................................................64

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List of Figures
Figure 1-1-Turbotricity Wind Turbine.......................................................................................11
Figure 2-1.Wind Turbine Blade Design (Tutorials, Alternative Energy, 2016). ......................12
Figure 2-2-Horizontal Axis Wind Turbine (works, 2006). ........................................................13
Figure 2-3. Vertical Axis Wind Turbine (Darrieus, 2003) ........................................................14
Figure 2-4-Permanent Magnet Generator (Comsol, 2012).....................................................15
Figure 2-5-Tilt Axis Wind Turbine Tower (College, 2016).......................................................15
Figure 2-6-Power Inverter (Abb, 2016)....................................................................................16
Figure 2-7-Wind Turbine Battery Bank (Energies, 2011)........................................................17
Figure 2-8-Dump Load for SSWT (Turbines, 2016)................................................................18
Figure 2-9-Off Grid SSWT System (Company, 2015).............................................................19
Figure 2-10-On-Grid SSWT System (Piggot, 2012)................................................................20
Figure 2-11-Direct Heating SSWT System (CO, 2015) ..........................................................20
Figure 2-12-Cup Anemometer (edsc, 2015) ...........................................................................23
Figure 2-13-Sonic Anemometer (Dame, 2011).......................................................................24
Figure 2-14-Propeller Anemometer (GmbH, 2016).................................................................25
Figure 2-15-Multiple Anemometers Measuring Wind Speed (Pidwirny, 2009) ......................27
Figure 2-16-Pitch Control (Dvorak, 2012) ...............................................................................28
Figure 2-17-Furling (Ltd., 2013)...............................................................................................29
Figure 2-18-Stall Control (Ltd., 2013) ......................................................................................30
Figure 2-19-Coning (mareenotmarie, 2009)............................................................................31
Figure 3-1 Isolation lock Millennium Controller .......................................................................35
Figure 3-2 Isolation lock Inverter .............................................................................................35
Figure 3-3 Oil level...................................................................................................................36
Figure 3-4 Hose connections...................................................................................................36
Figure 3-5 Connecting motor and hose...................................................................................37
Figure 3-6 Inserting steel pin on bottom of Ram.....................................................................37
Figure 3-7 Inserting steel pins at top of Ram ..........................................................................38
Figure 3-8-Loosening Nuts ......................................................................................................38
Figure 3-9- Lowering Turbine ..................................................................................................39
Figure 3-10 Turbine Lowered ..................................................................................................39
Figure 4-1 Block diagram of PVI 7200 electronics topology ...................................................41
Figure 4-2 Block diagram of PVI 3.6 electronics topology ......................................................42
Figure 4-3 Three phase resistive load.....................................................................................43
Figure 4-4 Single phase resistive load ....................................................................................43
Figure 4-5 Resistive load activated on controller ....................................................................44

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Figure 4-6 Brake setting applied on control ............................................................................45
Figure 4-7 Turbine Brake switch..............................................................................................45
Figure 5-1 Default wiring screw terminal WMT52 (Oyj, 2012) ................................................47
Figure 5-2 Sample Data form WTM52 ....................................................................................47
Figure 5-3 Lab Testing WMT52..............................................................................................48
Figure 5-4 Unitronics PSU.......................................................................................................48
Figure 5-5 WMT52 terminal screw connections......................................................................49
Figure 5-6 WMT52 Erected .....................................................................................................49
Figure 5-7 Terminal blocks supplying 24 VDC +/- ..................................................................50
Figure 5-8 Nokeval 7470 default wiring guide (Nokeval, 2015) ..............................................50
Figure 5-9 Nokeval 7470 DAC.................................................................................................51
Figure 5-10 V200-18-E3XB I/O Module ..................................................................................52
Figure 5-11 Linearizing function in Visilogic............................................................................52
Figure 5-12 Linearized wind speed values..............................................................................53
Figure 5-13 Linearized wind direction values..........................................................................53
Figure 5-14 Menu Display........................................................................................................54
Figure 5-15 Linking pages using memory bits ........................................................................54
Figure 5-16 Wind speed displayed on HMI.............................................................................55
Figure 5-17 Wind direction displayed on HMI .........................................................................55

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List of Tables
Table 3-1 Safety and Maintenance Equipment.......................................................................34
Table 5-1 Default wiring for WMT52 (Oyj, 2012).....................................................................46

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Abstract
The aim of this project was to do a complete analysis of the control system and all components
included in that system and their exact role in the system. Previous students have done
projects on the wind turbine but those previous students projects were aimed more at the PLC
side of the control system whereas this project will give a clear understanding of how the
system works and will enable students in the future to have a better understanding of the
operational procedure of the system.

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1 Introduction
Approximately 18% of electricity generated in Ireland in 2013 was generated by renewable
sources, to meet the EU targets for 2020 Ireland must increase the percentage of electricity
generated from renewable sources to 40%. To meet these targets approximately 32% of all
electricity generated in Ireland by 2020 will be generated by wind energy so it is by far the
most important renewable energy source in Ireland.
Wind turbines generate electricity from the wind by converting the kinetic energy in the wind
(some not all) to mechanical energy using turbine blades which rotate and are connected to a
generator (typically AC generator) which in turn converts the mechanical energy into electrical
energy. The AC voltage generated is known as wild AC as it is of variable frequency and
amplitude and must pass through power electronics before it can be used or exported to the
grid. Firstly the “wild” AC voltage is passed through a rectifier which converts it from AC to DC
voltage and then through an inverter which converts it back to useable AC voltage. Off Grid
wind turbines used for charging batteries and such do not need an inverter as they can be
charged direct from the DCvoltage from the rectifier. Anemometers are used to measure wind
speed and the data collected by Anemometer’s is essential in correctly sizing a wind turbine
and the control system that is needed to extract the maximum energy from the wind and
efficiently convert it to electrical energy.
The aim of this project is to fully understand the existing control system in which the wind
turbine and once data gathered from the anemometer is analysed determine if the existing
control system is optimising the available wind energy and if not what improvements, if any,
can be made to the system. The wind turbine in this report is a Small Scale Wind Turbine
(SSWT) and as such the report will concentrate on comparing and contrasting the various
SSWTs and the control systems available today rather than comparing to Large Scale Wind
Turbines.
The turbine in this report was built and installed in 2009 by a company from the Irish called
Turbotricity. Components of the system included a 2.5kW permanent magnet generator,
Aurora Power One Inverter, Aurora Wind Interface Box, Crouzet Millennium 3 Controller. A
Vaisala WMT52 Anemometer will be used to measure and log data which will be converted
using a Nokeval 7470 DAC and transmitted to a Unitronics V200-18-E3XB I/O Module which
will then be displayed on a HMI screen of a Unitronics V1210 PLC.

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Figure 1-1-Turbotricity Wind Turbine
The following are the objectives of this project:
 Develop a method statement for maintenance of wind turbine
 Fully understand and document turbine operation and control system
 Install Anemometer and log data
 Display Anemometer data on HMI screen

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2 Background
The Sustainable Energy Association of Ireland (SEAI) classify a wind turbine with a maximum
rating of 11kW or lower with a 3 phase grid connection as a SSWT or when connected to a
single phase supply with a maximum rating of 6kW.The wind turbine featured in this report
has a maximum rating of 2.5kW with a single phase connection so it falls into this category
SSWT also known as micro generation.
2.1 Components of Small Scale Wind Turbine System
The main components of a SSWT are as follows.
 Rotor blades
 Generator
 Tower
 Power Converters
 Battery banks (Off grid and stand-alone application)
 Dump load
2.1.1 Rotor Blades
Rotor blades in a wind turbine are of similar design to aircraft winds and are usually made of
fibre reinforced epoxy or unsaturated polyester. The rotor blades have an aerofoil design and
a curved surface which generates a lift force as the air flows past. Rotor blades can be
connected in 2 different design systems, Horizontal Axis Wind Turbines (HAWT) or Vertical
Axis Wind Turbines (VAWT).
Figure 2-1.Wind Turbine Blade Design (Tutorials, Alternative Energy, 2016).

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All HAWT use a lift force to rotate the turbine blades (some more advanced VAWT also use it
but not too common), the lift force is generated by the air flowing perpendicular to the blade.
As the air passes over the curved surface of the blade it creates a pressure difference above
and below which in turn creates the lift force which then rotates the blades. Most HAWT blades
face directly into the wind direction, these are known as upwind wind turbines. But some
HAWT blades face the opposite direction the wind is flowing, these are known as downwind
wind turbines. They extract the energy exactly the same as upwind turbines but are not as
efficient as the wind flow is disrupted by the turbine tower which reduces the wind speed and
thus reduces energy available. Most SSWT have wind vanes which guide the turbine blades
to face into the correctposition corresponding to the wind direction depending on whether they
are HAWT or VAWT.
Figure 2-2-Horizontal Axis Wind Turbine (works, 2006).
Some SSWT are of VAWT design which basically means the rotor blades are positioned
horizontal to the wind direction, this creates a drag force which rotates the blades in the
opposite direction that the wind is blowing. These type of devices are seldom used as they
have a very poor efficiency.

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Figure 2-3. Vertical Axis Wind Turbine (Darrieus, 2003)
2.1.2 Generators
Most SSWT use AC Permanent Magnet Generators which are connected to the rotor blades
by a generator shaft, generators convert mechanical energy into electrical energy.
” Essentially, a wire is wound around a stator made of material with high relative permeability.
Inside the stator you have a wheel, or rotor, which consists of a centre (made up of the same
material as the stator) and permanent magnets that create a strong magnetic field. These
permanent magnets are typically rare-earth elements, such as samarium for example.
When the rotor is set in motion a current is induced. That is because the electromagnetic fields
(EMF) of the permanent magnets on the rotor move past the coiled stator. As the magnets are
spaced out like teeth on the rotor, the strength of the EMF fluctuates up and down as the rotor
spins. It is this continuous flux that induces the current into the stator wire. Naturally, the faster
the rotor spins, the higher the voltage output (Comsol, 2012).”

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Figure 2-4-Permanent Magnet Generator (Comsol, 2012)
2.1.3 Tower
The top of a tower in SSWT is where the generator and rotor blades are housed, the blades
need to be raised high up off the ground to access better wind resource. The tower is of a
tubular steel design and in SSWT would vary in size dependant on the generator output and
location but usually wouldn’t exceed a height of 15m.The towers are generally tilt axis tower
which can be easily lowered or raised without the use of a crane and come in one section.
Single phase or three phase cabling, running internally in the tower, transmits the electricity
produced in the generator into the power electronics.
Figure 2-5-Tilt Axis Wind Turbine Tower (College, 2016)

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2.1.4 Power Electronics
“Power electronics has changed rapidly during the last thirty years and the number of
applications has been increasing, mainly due to the developments of the semiconductor
devices and the microprocessor technology” (F. Blaabjerg, 2006)
The power electronics needed in SSWT depends on whether its grid connected or for off grid
application. The power electronics consists of converters which convert the variable or “wild”
AC voltage into usable AC/DC voltage. In grid connected turbines the “wild” AC voltage first
passes through a rectifier which converts it to usable DC voltage. This DC voltage then passes
through an inverter which inverts the DC voltage back to usable AC voltage which can be
connected to the grid. Off grid turbines which are used to charge batteries don’t need an
inverter as the batteries are charged direct from the DC voltage from the rectifier. Some
systems have separate PLC controllers but it is more commonly to see the control system
inbuilt in the Inverters in SSWTwith inbuilt control which can be access from a front panel with
an LED display. The power electronics are usually housed in a separate control nearby the
wind turbine.
Figure 2-6-Power Inverter (Abb, 2016)
2.1.5 Battery Banks
“In off-the-grid systems batteries are an essential component used to store the energy
generated by your wind turbine so it can be reused later as needed. Batteries can also be
used as part of a grid-connected system to provide battery backup in the event the grid goes
down for a period of time. Batteries used with wind energy systems do have some unique
requirements and must be properly designed to fit the particular system you are planning to
implement (Bible, 2012).”

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“Most battery banks that are used with home energy systems use either 6 volt or 12 volt
batteries though bigger batteries are also available. In a battery bank the individual batteries
are interconnected into a string so that the voltage adds up to 12VDC, 14VDC or even 48VDC.
Now you might be thinking in the back of your mind, isn't that a bit low. My home electric
system uses 120 or 240 volts. Don't worry. The thing to keep in mind is that we are talking
about Direct Current (DC) voltage when it comes to batteries. When you are ready to use the
electricity for your home the inverter, a current conversion device that will be part of your wind
energy system, will convert the DC voltage in your battery bank into the 120 or 240 volts of
AC current that your home typically uses (Bible, 2012).”
Figure 2-7-Wind Turbine Battery Bank (Energies, 2011)
2.1.6 Dump Load
A dump load is a device that is used to dump excess electricity when it is not needed or battery
banks are full. A typical dump load is usually just a heating element or resistor, dump loads
are especially important in off grid wind turbines as overcharging the batteries shortens the
life span of the batteries. Dump loads are also used to regulate speed in wind turbines by
diverting the excess power generated in high wind speed to stop the turbine blades from
freewheeling and spinning out of control (Solar, Missouri Wind and, 2015)

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Figure 2-8-Dump Load for SSWT (Turbines, 2016)
2.2 Application of Small Scale Wind Turbines
SSWTs have typically been used in off-grid and remote location where connection to the grid
would be very expensive but more recently more grid connected SSWT are being installed as
the drive towards clean and sustainable energy supplies increases. SSWTs are broken down
into 3 different application usages which are as follows.
 Off-Grid
 On-Grid
 Heating
2.2.1 Off-Grid
SSWT are ideally suited for off grid application usually in remote location where there is no
access to grid supplied electricity. They are relatively expensive per kWh compared to grid
supplied energy and usually take a lot longer than LSWT to repay the initial investment but
when comparedto the costof connection to the grid in mostremote location they are financially
feasible .Off grid SSWT use battery banks to store electricity generated from the wind turbine,
a converter converts the AC voltage produced by the generator to DC Voltage from which the
batteries can be charged, an inverter then converts the DC voltage from the batteries to AC
voltage which can then be used for domestic or agricultural applications. Some stand-alone
systems such as lighthouse or emergency telephones on the side of a motorway can be run
from an Off-Grid SSWT by storing energy in a battery to run off. Off grid system also need a
charge controller.
A charge controller

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“Is a device that regulates the current and or voltage that you can put into your battery or
batteries and it will not allow you to over charge and ruin your battery or batteries by controlling
the voltage at the battery level? Onceyour battery or batteries are charged the controller kicks
in and opens, diverts, or shunts the generator circuit (windpower, 2015).”
Figure 2-9-Off Grid SSWT System (Company, 2015).
2.2.2 On-grid
Grid tied SSWT are used to supplement and reduce the electricity supplied from the grid, they
cannot total replace the grid supplied electricity as the energy produced by the wind turbine is
unpredictable and is concentrated in periods of high wind. The SSWT system for an off-grid
and on-grid turbine are pretty similar. The main difference is battery banks are used to store
the power generated in off-grid systems whereas on-grid system are connected into grid
supplied electricity once it has passed through various converters. By replacing electricity
purchased from the grid optimises the value of installing a SSWT and also excess electricity
produced can be sold back to the grid.

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Figure 2-10-On-Grid SSWT System (Piggot, 2012)
2.2.3 Direct Heating
Direct Heating is really only suitable for sites that have a high heating demand, it is a relatively
simple system that uses the voltage generated by the turbine to power a heating element in a
large tank thus heating the water. Large well insulated tanks keep the water hot and usable
for periods when the wind isn’t blowing and the turbine isn’t producing energy. As direct
heating becomes more popular the price of the systems are dropping and are becoming more
financially feasible. The system is essentially the same as on grid SSWT
Figure 2-11-Direct Heating SSWT System (CO, 2015)

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2.3 Anemometer
An Anemometer is an instrument used for measuring wind speed and wind direction both of
which are very important when assessing if a site is suitable for a wind turbine. Accurate
measurements are vital as the wind speed has a cubic relationship with wind power and a
10% error in wind speed results in a 30% error in wind power, when measuring wind speed
the accuracy should be ideally kept to +- 2%. There are 3 main types of Anemometers used
for measuring wind which are:
 Cup Anemometer
 Sonic Anemometer
 Propeller Anemometer
“Remote sensing techniques are now being used to measure the wind speeds at wind farm
sites. The technology available for this is being developed rapidly, and although the use of
remote sensing devices on wind farm sites is not currently widespread, it is expected to
become more widely used in the near future. Remote sensing devices are essentially ground
based devices, which can measure wind speeds at a range of heights without the need for a
conventional mast. There are two main sorts of devices: Sodar (Sound Detection and
Ranging), which emits and receives sound and from this infers the wind speed at different
heights using the Doppler Shift principle; Lidar (Light Detection and Ranging), which also uses
the Doppler Shift principle but emits and receives light from a laser. Sodar has been used for
assessing wind farm sites for some years, particularly in the US and Germany. It is often used
in combination with conventional anemometry and, historically, the results have been used to
provide more information to better understand the patterns of the wind regime at a site, rather
than necessarily using the data in a direct, quantitative way.

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Recently, some wind energy specific Sodar products have come onto the market and
experience is currently being gained from these new devices. Lidar devices have made an
entry into the wind market over the last few years and two main commercial models are
currently widely available with additional models now entering the market. Published papers
on the devices show they are capable of achieving impressive accuracylevels in simpleterrain
and it is expected that their use in wind energy applications will increase. The clear merit of
remote sensing devices is that they do not need a mast. However, Lidar devices, in particular,
are relatively expensive to purchase and both devices draw significantly more power than
conventional anemometry, so for remote sites a local, off grid power supply solution would be
needed (EWEA, 2016).”
2.3.1 Cup Anemometer
The Cup Anemometer is the mostcommonlyused anemometer, current industry standard cup
anemometers have 3 hemispherical cups each mounted on a horizontal arm, at equal distance
and angle apart from each other, that rotate on top of a vertical shaft. The passing wind is
captured by the hollow part of the cup which rotates the cups in a horizontal direction
proportional to the wind speed and by counting how many times the cups fully rotate over a
set period of time the wind speed is measured. (Inc, 2015)
Some cup anemometers have tiny magnets attached to the cups and each time they pass a
magnetic detector an electrical pulse, which represents a single rotation is completed, is sent
to a data logger.
Cup Anemometers are relatively simple and cheap and can be easily installed, but depending
on the accuracyneeded and climateconditions more expensive high quality cupanemometers
should be used. In colder environments icing can be an issue and heaters are needed to
prevent this occurring, also for measurements over a long period of time heavy more robust
anemometers are needed. Most Cup Anemometers don’t come with a wind vane, to measure
wind direction, so this is another drawback of Cup Anemometers.

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Figure 2-12-Cup Anemometer (edsc, 2015)
2.3.2 Sonic Anemometer
Sonic Anemometers use ultrasonic sound waves to measure wind, pairs of transducers
(sensors) measure how long it takes for sound pulse to travel between them. The transducers
are arranged in 3 pairs on 3 different axis which measures wind speed three dimensionally
and because of this the wind direction can also be determined. Sonic Anemometers are the
most accurate and reliable anemometers which also makes them the most expensive. The
accuracy is mainly due to the much higher sampling rates, some high quality sonic
anemometers are capable of taking measurements approximately every 20 milliseconds.
Sonic Anemometers have no moving parts which increases the reliability and they are capable
of operating in extreme conditions but the data quality can be significantly affected in heavy
rain when water droplets on the transducers impair the pulse signals. When this occurs the
affected data is usually discarded to reduce any error in overall data collected. Most Sonic
Anemometers also have heaters to prevent ice building up on the transducers and affecting
the quality of measurements (Science, 2016).

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Figure 2-13-Sonic Anemometer (Dame, 2011)
2.3.3 Propeller Anemometer
Propeller Anemometers work very similarly to wind turbines, they use propeller shaped blades
which rotate in the wind.
“Propeller anemometers measure the air flow from any vertical and horizontal wind direction.
They are usually applied in Wind Park monitoring by showing how the turbines react to airflow.
A propeller anemometer utilises a fast-response helicoid propeller and high-quality tach-
generator transducerto produce a DCvoltage that is linearly proportional to air velocity. Airflow
from any direction may be measured, but the propeller responds only to the component of the
airflow that is parallel to its axis of rotation. Off-axis response closely approximates a cosine
curve with appropriate polarity; with perpendicular air flow, the propeller does not rotate. The
output signal of propeller anemometers is suitable for a wide range of signal translators and
data logging devices (GmbH, 2016).”
Propeller Anemometers output an Analog DC voltage signal which is proportional to wind
speed by using this method the accuracy of the data signals are very high. Some Propeller
Anemometer have screens that display the wind speed as it is being measured. The Propeller
Anemometer differs from other Anemometers as it generates an Analog signal, usually 0-10v.
This means, say for wind speed range from 0-100km/hr for every 0.1 volts it corresponds to
1km/hr wind speed i.e. If it detects an output of 5.5v the corresponding wind speed for 5.5v
will be 55km/hr, for example:
5.5𝑣
.1𝑣
×
1𝑘𝑚
ℎ𝑟
= 55𝑘𝑚/ℎ𝑟

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Equation 2-1 Converting Analog signal to Wind Speed
Figure 2-14-Propeller Anemometer (GmbH, 2016)
2.3.4 Data Logging
Most Anemometers have data loggers for storing data and measurements recorded, data
loggers store this data in either a digital or analog format, some anemometers have built in
Digital Analog Converter (DAC)/Analog Digital Converter (ADC) but a separate DAC/ADC will
be needed in most cases. Data can be extracted from the data loggers with various different
methods, ideally data could be sent via a radio transmitter to a Remote Telemetry Unit (RTU)
as the anemometers is actually measuring it and as the RTU would store it there would be no
need for a data logger but this is location dependant as a site with poor radio signal would not
be suitable.
Another method would be to connectto the serial port on the anemometerwith a RS-486 cable
and transfer the data to laptop. Some anemometers have removable micro-SD cards which
store the data and can simply be removed and inserted into a PC or laptop to transfer data.
Anemometers can also be hardwired to PLC units with built in or removable ADC/DAC
converters dependant on whether the data from the anemometer is analog or digital.

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2.3.5 Measuring Wind Speed
When measuring wind speed at a site only anemometers covered by IEC-61400 standards
should be used, also each anemometer must be individually calibrated and have an official
ISO 3966 1977 certificate of compliance. Anemometers used for measuring wind speed over
long periods of timeshould be recalibrated after use to make sure there have been no changes
while measuring (Große, 2016).
“When erecting an Anemometer the impact of the mast (tower), on which the anemometer will
sit, on wind speed measurements should be taken very seriously and proper procedures
should be followed to reduce the impact it has on accurate measurements. Also more than
one anemometer should be used and placed at varying heights to give more accurate and
detailed measurements, below are a list of steps to follow for when installing anemometers.
 All wind sensors mustbe fitted absolutely vertically. Even small deviations lead to skew
winds and therefore to wrong measurements.
 Traverses keep the sensors as far away as possible from shaded or turbulent areas.
However, the traverse must not start swinging. This can not only influence the
measurement, but also lead to bearing damage of the transmitter.
 The top-anemometer is to be placed centrally on the top of the tower. It must be
streamed on from all directions without obstruction. For the last piece (minimum 0.5 m)
of the pillar, one should choosea diameter whichis similarto the shaft of the transmitter
and which corresponds to the set-up used during the calibration of the wind sensor in
the wind channel. Next to the anemometer there should only be a thin lightning
conductor.
 The lower anemometer(s) should be fitted on a vertical pipe attached to a traverse, so
that the anemometer stays 30 to 60 cm over the traverse. A traverse directly under the
anemometer can influence measuring! The fitting mustbe such that the transmitter lies
at a 45° angle to the main wind direction, which is usually known approximately.
 With a cylindrical tower, the length of the traverse should be at least 7-times of the
tower diameter. If a framework structure is used for the mast (width up to 30 cm), the
traverse length should be around 1 m long.
 The wind vane should be fitted as high as possible on a traverse, but at least 1.5 m
below the top anemometer. The traverse is to be fitted as described before. For fitting

27
the vane you need a compass or a good map with a small scale in order to locate a
prominent fixed point on the horizon. Mostly one has to screw the wind vane onto the
tower while it is still lying on the ground. A good angle-measuring tool also helps.
 The lightning rod (thickness approx. 2 cm) must have a distance of 50 cm from the
anemometer and must be free from vibrations. The lightning rod should be over the
anemometer at a 60° angle.
 The best place for all cables is within the tower. The dead weight of free hanging cables
over 50 m in length has to be secured with an additional rope. If fitting within the tower
is impossible, you must fix the connections to tower and traverses at intervals of one
metre. Be sure that no loose cables are flying in the wind. Also avoid contacts with
sharp edges. Every little stress on the cable can lead to damage in the course of long-
term operations! (GmbH, 2016).”
Figure 2-15-Multiple Anemometers Measuring Wind Speed (Pidwirny, 2009)
2.4 Speed Control
Speed control is essential in wind turbines for numerous different reasons, the first and most
obvious is to prevent the turbine from being damaged during storms or periods of high wind
speeds. Each turbine has a cut out speed given by the manufacturer, the cut out speed is the
maximum wind speed as recommended by the manufacturer for each turbine to operate in
and where operating above this wind speed is likely to cause damage to the wind turbine.
Wind Turbine blades can rotate at up to 7 times the actually wind speed so measures must
be taken to curtail the speed from exceeding the cut out speed. There are several ways of
doing so which are as follows:
 Pitch Control

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 Furling
 Coning
 Active Stall
 Electronic Torque/Stall Control
Speed control also prevents generating more energy than the system can handle which can
result in overheating or damage to cables and other components. Also speed control is
important for constant speed generators as the shaft and rotor rotational speed must remain
the same for the generator to operate at the optimum efficiency.
2.4.1 Pitch Control
Pitch control is mainly used in Large Scale Wind Turbines but some SSWT manufacturers do
offer it. Pitch control uses a mechanism which adjusts the angle the turbine blades are with
regards to the wind direction, when wind speeds exceed the recommended cut out speed the
pitch mechanism angles the blades so they are horizontal to the wind direction and no lift force
is acting on the blades which stops the blades from rotating. Pitch control is also used for
regulating the power output from the turbine by adjusting the angle of the blades so that they
rotate at the same speed as a synchronous generator.
Figure 2-16-Pitch Control (Dvorak, 2012)

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2.4.2 Furling
“Furling is the process of forcing, either manually or automatically, the blades of a wind turbine
out of the direction of the wind in order to stop the blades from turning. Furling works by
decreasing the angle of attack, which reduces the induced drag from the lift of the rotor, as
well as the cross section. (Darling, 2013). “
Furling is done manually by physically cranking the turbine out of the wind using spring hinges
to adjust the rotor and blade angles relative to the wind direction, this is a simplemethod which
essentially is folding the turbine rotor and blades to a position so they do not rotate. Furling
can be done either horizontally or vertically and automatic furling uses the same principle as
manual furling but uses sensors and hydraulics to adjust the rotor when wind speeds get too
high.
Figure 2-17-Furling (Ltd., 2013)
2.4.3 Active Stall Control
“Stall-regulated wind turbine have their blades designed so that when wind speeds are high,
the rotational speed or the aerodynamic torque, and thus the power production, decreases
with increasing wind speed above a certain value (usually not the same as the rated wind
speed). The decrease in power with increasing wind speeds is due to aerodynamic effects on
the turbine blades (regions of the blade are stalled, propagating from the hub and outwards
with increasing wind speeds). The blades are designed so that they will perform worse (in
terms of energy extraction) in high wind speeds to protect the wind turbine without the need
for active controls. The benefit of stall-regulation over pitch-regulation is limited the capital cost
of the turbine, as well as lower maintenance associatedwith more moving parts. Like the pitch-

30
regulated wind turbine, stall-regulated wind turbine also have brakes to bring the turbine to a
halt in extreme wind speeds.” (Chen, 2011).
Stall control doesn’t work on variable speed turbines and also the force acting on the blades,
when in stall-regulation, can be very high leading to high vibration which increases noise and
also can damage the blades.
Figure 2-18-Stall Control (Ltd., 2013)
2.4.4 Coning
Coning is a very simple method of speed control used on downwind turbines, the blades have
spring hinges and as the wind speed increases the blades simple start to bend back reducing
the force exacted on the blades

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Figure 2-19-Coning (mareenotmarie, 2009)
2.4.5 Electronic Torque/Stall Control
Although not widely used electronic torque is a very effective way of regulating speed, as the
current increases so does torque. So when high wind speed occur the power electronics can
increase the current being drawn which increases torque on the rotor shaft which in turn
reducing the speed of rotor.

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3 Safety
Proper safety procedures are vitally important when working on or nearby live electrical
equipment to ensure the health and safety of employees and also members of the public who
could be at risk. Before a method statement is drafted an electrical risk assessment must be
done on the equipment or system in question by trained personnel and once hazards are
identified the following procedures as set out in Chapter 5, Regulation 85 of the Safety, Health
, and Welfare at Work (General Applications) Regulations 2007 Part 3 must be followed.
“Switching and isolation for work on equipment made dead. 85.
(1) An employer shall ensure that— (a) subject to paragraph (2), where necessary to
prevent danger, suitable means (including, where appropriate, methods of identifying
circuits) are available to switch off the supply of electricity to any electrical equipment
and to isolate any electrical equipment, (b) every switch,circuit breaker or other control
device provided under subparagraph (a) is, where necessary to prevent danger, (i)
clearly marked to indicate the “ON” and “OFF” positions, unless these are otherwise
self-evident, and (ii) readily accessible for authorised persons and in a suitable and
adequately lit location, and 42 (c) adequate precautions are taken to prevent the
operation of any switchwhile carrying current where that switchis not capable of safely
interrupting normal load current. (2) Paragraph (1) does not apply to electrical
equipment which is itself a source of electrical energy, provided that adequate
precautions are taken to prevent danger (hsa, 2007).”
3.1 Method Statement
A method statement is a vital document that informers workers of the potential risks and
hazards in a particular work environment, it also details the correct procedure to follow when
work or maintenance is to be carried out on a particular task or activity. Method statements
are site specific and should be tailored to the environment and job specifications in which the
activity will be carried out.

33
“Whilst there is no standard format for a method statement, the following aspects may need
consideration:
 working systems to be used;
 arrangements for access e.g. to roofs;
 methods for safeguarding existing structures;
 structural stability precautions, e.g. temporary shoring arrangements;
 arrangements for protecting the safety of members of the public;
 plant and equipment to be used;
 health protection arrangements, such as the use of local exhaust ventilation
and respiratory protection, where hazardous dusts and fumes could be
created;
 procedures to prevent local pollution;
 Segregation of specific areas; (Direct, n.d.).”
3.1.1 Electrical Risk Assessment
An electrical risk assessment was carried out with Mr Brendan O Heney, Senior Electrical
Technician from LIT, who was responsible for installing the control system for the wind turbine.
The control system has 2 separate power sources feeding it and these must be isolated or
made dead before any work can be carried out.
1. The first source of electrical supply was 3 phase 0-600 Variable AC voltage and
variable frequency from the turbine generator which was connected to the Wind
Interface Box (Rectifier) and Millennium controller in the control room. An isolation
switch directly between the 3 phase supply and Wind Interface Box cuts this supply
when switched to the OFF position, properly electrical locks and tags are to be used
when doing so.
2. The next electrical hazard identified was the 230 V AC Main supply to the Aurora
Inverter, this also had an isolation switch to cut supply, once switched to the OFF
position proper electrical locks and tags are to be used to ensure cutting off the
electrical supply safely.
3. The control system also contained an isolation switch that activated the hand brake on
the wind turbine, which prevents the turbine blades from rotating and thus generating
electricity, this must be switched to the ON position before any work is carried out.
4. Once these 3 steps have been implemented a multi-meter is used to carry out tests to
ensure all electrical supply have been isolated and are safe to work on.

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3.1.2 Equipment
Table 3-1 Safety and Maintenance Equipment
Safety Equipment/PPE Electrical Isolation Turbine Lowering Equipment
 Steel Toecap Safety
Boots
 HI-Visibility
Vest/Jackets
 Hard Hat
 Barriers or tape to
cordon off area
 Safety Tagout Kit
 Multi Meter
 Flowfit Hydraulic
Cylinder/Ram
 TEC 1.5 Kw Electric
Motor
 Hydraulic Hoses
 Hydraulic Oil
 Extension Lead
 1m Tommy Bar
 41mm Socket Set
 30mm Diameter
 300mm Steel Pins

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3.1.3 Method
1. Ensure area is clear of unauthorised personnel before work can commence, lock gate
and cordon off work area.
2. Bring turbine to a stop using
3. Carry out Electrical Isolation as set out in Electrical Risk Assessment locking out and
tagging isolation and hand brake switches as seen in figures 3-1 and 3-2
Figure 3-1 Isolation lock Millennium Controller
Figure 3-2 Isolation lock Inverter
4. Uses multi meter to check if electrical supply is killed.
5. Check Oil levels in hydraulic ram are sufficient (as seen in figure 3-3), if below required
level refill.

36
Figure 3-3 Oil level
6. Connect hoses to motor and hydraulic ram, hose connected to bottom fitting of motor
must be connected to bottom fitting on hydraulic ram and vice versa for top fitting.
Figure 3-4 Hose connections
7. Move hydraulic ram into position flat on ground next to wind turbine.

37
8. Connect motor to extension lead and plug extension lead into mains supply turning on
motor as seen in figure 3-5.
Figure 3-5 Connecting motor and hose
9. Tilt hydraulic ram up using control levers until pin holes match up on turbine and ram.
10. Place steel pins through pin holes at top and bottom of ram and ensure they are secure
before continuing as seen in figures 3-6 and 3-7.
Figure 3-6 Inserting steel pin on bottom of Ram

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Figure 3-7 Inserting steel pins at top of Ram
11. Use 41mm socket fitting and 1m tommy bar (for extra torque) to loosen nuts on turbine
stand (as seen in figure 3-8), do not remove fully until sure hydraulic ram is operating
correctly, then remove nuts 1 at a time.
Figure 3-8-Loosening Nuts

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12. Slowly lower wind turbine, using control lever, until it is flat on the ground. See figures
3-9 and 3-10.
Figure 3-9- Lowering Turbine
Figure 3-10 Turbine Lowered
13. Maintenance check and work can now be carried out if needed.
14. Slowly raise turbine up using control lever until it is flush on turbine stand and reinsert
nuts and retighten.
15. Once turbine is secure remove steel pins and lower hydraulic ram, plug out and
disconnect hoses.

40
16. Remove isolation locks and tags from switches, and turn ON isolation switches for
inverter and millenium controller.
17. Do not switch handbrake OFF for at least 5 minutes after inverter has been initialized
as no current will be drawn and turbine blades will rotate uncontrolled and may cause
damage to turbine.
18. Release hand brake switchand observe system is running correctly before leaving and
locking up control room.

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4 ControlSystem Analysis
This section of the report will examine the process and components involved in converting the
variable 3 phase AC voltage generated by the turbine generator to the 230 AC voltage which
is exported to the grid and also how the system is controlled.
4.1 Conversion Process
1. The 2.5kW permanent magnet generator, which sits at the hub of the wind turbine,
produces 3 phase variable VAC which is connected to an Aurora Power One Interface
Box PVI 7200 (Rectifier).
2. The PVI 7200 has a maximum input of 400 VAC and maximum output of 600 VDC,
the 3 phase VAC is converted to VDC by the PVI 7200 using a system of power
electronics such as diodes, capacitors and transistors (as seen in figure 4-1) which
then must undergo another conversion process in the Aurora Power One Inverter PVI
3.6.
Figure 4-1 Block diagram of PVI 7200 electronics topology
3. The PVI 3.6 Inverter has a maximum input value of 600 VDC and by using a complex
configuration of electronic components such as capacitors, diodes and transistors (as
seen in figure 4-2) converts the inputted VDC to 230 VAC 50 Hz for export to the grid.

42
Figure 4-2 Block diagram of PVI 3.6 electronics topology
4.2 Speed Control
The system comes with 2 resistive loads or dump loads as mentioned in section 2.1.6., a three
phase load figure 4-3 which is used for speed control and a single phase load figure 4-4 which
is used for dumping excess energy generated (if any). These resistive loads are basically just
heating elements as can be seen from figures 4-3 and 4-4 and any excess energy generated
is dissipated as heat through the single phase dump load. The three phase resistive load is
used for controlling the speed, when the DC voltage from the rectifier reaches a certain value
the three phase load is activated which increases the resistance in the circuit which in turn
forces the generator to draw more current which causes it to stall and rotor shaft to stop
turning.
The system also has a brake switch which when turned to the ON position shorts out the
generator, this is only to be used when the turbine has been already brought to a stop through
the controller, and prevents the rotor from turning when lowering or raising the turbine.

43
Figure 4-3 Three phase resistive load
Figure 4-4 Single phase resistive load
The manufacturer pre-programmed the controller to active the three phase resistive load once
the voltage from the rectifier hits 530 VDC and disconnect the load once the voltage drops
below 430 VDC. But since installation the program has been modified numerous times, by
previous students, and now the resistive load will activate once the voltage exceeds 200 VDC
which is only 1/3 of the rated output of the rectifier and by limiting the voltage from going above
200 VDC the power output and overall efficiency of the system is greatly reduced.

44
This is set using a 0-10v analog signal for the voltage range 0-600VDC, this linearizes the
voltage range with the analog value. So when the output voltage is at 0v (min value) this
corresponds with 0.00v (min value) on the analog scale, and when the voltage reaches 600v
(max value) this will correspond to 10v (max value) on the analog scale.
So for every 1v of an increase in output voltage will mean an increase of 16.67mv on the
analog scale, this was calculated using the following formula.
1v output=
𝑎𝑛𝑎𝑙𝑜𝑔 𝑟𝑎𝑛𝑔𝑒
𝑣𝑎𝑟𝑖𝑎𝑏𝑙𝑒 𝑟𝑎𝑛𝑔𝑒
=
10𝑣
600
= 0.01666 𝑜𝑟 16.67𝑚𝑣
Figure 4-5 shows the resistive load activating at 3.3v on the analog scale which correspond to
200 VDC on the output. The value of 167v in the display can be disregarded as the output
voltage dropped from 200v while the picture was being taken.
Figure 4-5 Resistive load activated on controller
Figure 4-6 shows the brake being applied, which is the generator being stalled, this happens
after the resistive load is applied and as can be seen it also activates at 3.3v analog which
again is 200 VDC, again the output voltage in the picture can be disregarded for the same
reason as mentioned for figure 4-5.

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Figure 4-6 Brake setting applied on control
Figure 4-7 Turbine Brake switch

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5 Anemometer
A Vaisala WMT52 Anemometer was installed to log wind data, the WMT52 is an ultra-sonic
anemometer that uses 3 ultrasonic transducers to measure wind speed. And as mentioned in
chapter 2.3.2 ultra-sonic anemometers measure the time it takes for sound pulses to travel
between the transducers and thus measures the wind speed and also the wind direction. The
data out from the WMT52 is a digital signal so to convert wind speed and wind direction to an
analog signal a Nokeval 7470 Digital to Analog converter was used which would in turn
transmit the analog signal to a Unitronics V200-18-E3XB I/O (input/output) module and could
be displayed on V1210-T20BJ HMI touch screen. An RS-485 cable was hardwired to the
screw terminals of the WMT52 (as there was no 8-pin M12 connector on the WMT52) to
connect to the Nokeval 7470 for power and data transfer. Both the Nokeval 7470 and WMT52
were sent off to be professionally calibrated before project commenced.
5.1 Installing Anemometer
Before the Anemometer was installed it was tested in the lab (see figure 5-1) to ensure it was
powering up correctly and data was being transmitted, as mentioned in chapter 1 this was
done in conjunction with 3rd
year Electronic Engineering student Nathy Brennan, using the RS-
485 default configuration as seen in table 5-1 and figure 5-1.
Table 5-1 Default wiring for WMT52 (Oyj, 2012)

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Figure 5-1 Default wiring screw terminal WMT52 (Oyj, 2012)
5.1.1 Testing Anemometer
The testing was carried out by connecting wires to the screw terminal (as configured in figure
5-1) of the WMT52 to an Arduino ATMega 2560 microcontroller,HTerm software package was
used to open up a COM port between the microcontroller and laptop and a USB cable used
for sending and receiving data (see figure 5-3). The sample data received from the
anemometer is in digital Hexadecimal form which is converted into m/s for wind speed and
degrees for wind direction by the HTerm software. Figure 5-2 shows a sample of the data
received where Dm corresponds to direction in degrees, relative to North, i.e. 90 = East, Sm
refers to wind speed in m/s.
Figure 5-2 Sample Data form WTM52

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Figure 5-3 Lab Testing WMT52
5.1.2 Power Supplies
Both the WMT52 and Nokeval 7470 require 24 VDC power supplies, the Unitronics PLC power
supply is 230 VAC from the grid but its Power Supply Unit (PSU) can provide 24 VDC out from
its terminals so2 x 24 VDC power supplies on din rail mounted terminal blocks were generated
for the WMT52 and Nokeval 7470 respectively. To do this the Unitronics was stripped of all
wiring from previous projects with the 230 VAC grid supply to the PSU established 1st
, once
the PSU was receiving power the 2 x 24 VDC power supplies (figure 5-4) were created and
now the Nokeval 7470 could be installed.
Figure 5-4 Unitronics PSU

49
5.1.3 Installing Anemometer
The anemometer was hardwired to the screw terminals as per default wiring guide (see figure
5-1) and mounted on a steel pole before being raised, anemometers should ideally be raised
at the same height of the hub of the wind turbine but in this casewas not possible as the length
of the RS-485 cable provided was not long enough. Once the RS-485 cable was wired to the
screw terminals of the WMT52 (see figure 5-5) and an earth cable was also connected for
grounding the anemometer was raised.
Figure 5-5 WMT52 terminal screw connections
Figure 5-6 WMT52 Erected
Next the brown and yellow wires from the RS-485 were connected to the 24VDC + din rail
mounted terminal blocks power supply from the PSU and the pink and red wires connected to
the 24VDC – terminal blocks from PSU also, Figure 5-7.

50
Figure 5-7 Terminal blocks supplying 24 VDC +/-
The blue and grey wires for data in and data out were connected to the Nokeval DAC (see
chapter 5.1.4) and the remaining 2 wires white and green, from the RS-485 cable, were
terminated as they are of no use in the RS-485 default wiring configuration.
5.1.4 Installing Nokeval 7470 DAC
The Nokeval 7470 was mounted on a din rail inside the Unitronics PLC and was connected
up as per default wiring guide RS-485, see figure 5-8, on the input side the grey wire (data in
from WTN52) connected to terminal 1 and blue wire (data out from WMT52) to terminal 2
Figure 5-8 Nokeval 7470 default wiring guide (Nokeval, 2015)

51
24 VDC + connected into terminal 12 and 24 VDC – connected to terminal 11 also. As
previously mentioned the DAC was sent away to be calibrated before use, the analog outputs
are a 4-20mA range. Channel 1 of the analog output was calibrated for a wind speed range of
0-60 m/s meaning an output of 4mA= 0m/s and 20mA= 60m/s and as the range is 16mA/60m/s
for every increase of 266.7μA current signal is equal to a 1m/s increase in wind speed.
Terminals 13 + and 14 - were connected to Analog input 0 + and – on the V200-18-E3XB I/O
module (see figure 5-9).
Figure 5-9 Nokeval 7470 DAC
Analog out channel 2 on the DAC was calibrated for wind direction, again 4-20mA was the
signal range which corresponded to 0-360° for direction with 0°= North. As the range is
16mA/360° as the signal increases by 44.44μA = 1° change in wind direction clockwise.
Terminals 16 + and 17 – (see figure 5-10) from the DAC were then connected to Analog Input
1 +/- on the V200-18-E3XB (see figure 5-11).

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Figure 5-10 V200-18-E3XB I/O Module
5.2 Displaying Anemometer Data
.The data from the anemometer is displayed on a Unitronics V1210 HMI in conjunction with a
V200-18-E3XB snap in I/O module which connects into the V1210 as seen in figure 5-10. The
snap in I/O module receives the 4-20 analog signals from the DAC into analog inputs 0 and 1
and these inputs are assigned to Memory Integers which are internally addresses in the I/O
list. To display this data a ladder and HMI program had to be created using Unitronics Visilogic
V9.8.22, to convert the 4-20mA signals to values that can be displayed the first step done is
what is called linearizing.
Figure 5-11 Linearizing function in Visilogic

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Linearizing is converting the analog signals to bit values which allows the actual measured
values then to be displayed, in this case wind speed in m/s and wind direction in degrees.
Visilogic has an option to use 12 bit or 14 bit ,the 12 bit option gives quicker measurements
but the 14 bit option is more accurate so the 14 bit. When selecting the bit resolution it is very
important to select the correct bit range and the correct baud rate, from the manual the bit
range for 14 bit goes from 3277-16383 and a baud rate speed 115200. If the correct bit range
and baud rate are not configured the actual measured values displayed on the HMI will be
incorrect. For wind speed 0 m/s will be equal to 3277 bits and 60m/s will be equal to 16383
and for the wind direction 0° is equal to 3277 and 16383 is equal to 360°, once linearized the
display range values are stored in memory integers which are then used to program the
measured values on the HMI. Figures 5-12 & 5-13 show the configured ranges for both wind
speed and direction, the wind speed for display are stored in memory integer MI 20 and wind
direction MI 21, these are the memory integers that are used to program display in HMI. Note
that there is a 1 decimal offset for the max measures values so Y2 in figure 5-12 is 60.0 m/s
not 600m/s and in figure 5-13 Y2 is actual 360.0° not 3600°.
Figure 5-12 Linearized wind speed values
Figure 5-13 Linearized wind direction values
Four display pages were then created for the HMI display, a Menu page from whichthe 3 other
pages Wind speed, Wind direction and Trends) could be accessed by buttons which linked
the pages. While creating the pages each page was assigned a memory bit address that are
used to link buttons to pages and thus navigate through the HMI display also on each page a
back button was created which when pressed jumps back to the menu page.

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Figure 5-14 Menu Display
Figure 5-15 Linking pages using memory bits

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Figure 5-16 Wind speed displayed on HMI
Figure 5-17 Wind direction displayed on HMI

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6 Discussion
One of the aims of this project was to fully understand how the control system and components
of the system work and to analysis whether the system is configured to extract the optimum
energy available and optimizing maximum efficiency.
Another aim was to carry out a safety assessment and produce a method statement which
would be of use for further work carried out on the system.
And also erect an Anemometer and log and display data from the Anemometer on a HMI
screen. This chapter will discuss and highlight issues that arose over the courseof the project.
6.1 Control System and Components
While analysing the system the most obvious issue in the design was the variation in rated
power between the generator, rectifier (wind interface box) and inverter. The permanent
magnet generator has a power rating of 2.5kW while the rectifier has a power rating of 7.2kW
and the inverter has a power rating of 3.6kW, meaning the rectifier can handle just under 3
times the power generator by the generator which seems to be greatly oversized and just adds
to the initial capital cost of the system unnecessarily.
Another issue was the Crouzet Millennium 3 Controller and its role in the system, the original
design of the system as set out in the manufacturers manual does not include this controller.
The manual states that the Aurora inverter can be used to programme the control setting in
the system from its control panel so it seems to be an unnecessary addition to the system and
also the fact the controller has a very complicated program and the programming language its
self is a combination of ladder logic and function block which further complicates matters.
On the software side of things the controller has a brake setting which activates when the
output from the rectifier reaches 200 VDC while the rectifier itself has a maximum output
voltage rating of 600 VDC. This setting prohibits the system from utilizing anywhere near the
maximum energy output from the available energy resource and dramatically reduces the
efficiency of the system.
As mentioned in section 4.2 the system uses a three phase resistive load as a braking
mechanism, when this three phase load is activated the rotor and turbine blades stop turning
almost immediately. This sudden stop could in theory cause damage to the rotor and turbine
blades if it has not done so already.

57
6.2 Safety
The system has two electrical isolation switches whichwhen turned to the OFF position isolate
power supply from the grid and also the power supply from the generator but the system also
has a brake switch for the turbine which looks very similar to the isolation switches. In the
event of maintenance being carried out or the turbine needs to be lowered the two isolation
switches need to be in the OFF position but the brake switch must be switched to the ON
position which may cause some confusion and become a safety hazard.
6.3 Data logging
The anemometer was sent away to be calibrated before this project commenced and was
calibrated for a wind speed range of 0-60 m/s and for wind direction 0-360°. While the
calibration for wind direction is not an issue the calibration for wind speed caused some
problems when displaying it on the HMI screen. 1m/s is equal to 3.6 km/h so the anemometer
was calibrated up to a wind speed of 216 km/h which is excessively high.
The Visilogic software had two options of establishing communicationbetween the I/O Module
and laptop which are USB to mini USB cable and a serial to USB cable which needs a special
adapter supplied from Unitronics. Initially the chosen method of communication was the USB
to mini USB cable as this was the method previous students had used. But during the course
of the project this method of communication failed, replacement cables were tried, different
versions of driver software were tried but to no avail. Eventually after a lot of time spent trying
to remedy the issue it was established that the mini USB port on the V1210 was the problem
and once the adapter for the serial to USB cable was located this was the method of
communication used for the duration of the project.

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7 Conclusion and Recommendations
As previously mentioned the system is very inefficient, one way of improving the efficiency
and increasing the output power is by adjusting the brake setting from 200VDC to a
recommended setting of 400 VDC on the Crouzet Millennium Controller, however this is a
complicated piece of software, and due to time constraints it was not possible to do so but is
advisable to do so in the future.
The addition of the Millennium Controller in the system, in the opinion of this student, seems
unnecessary and just overcomplicates the system. Further investigation as to why the
manufacturer chose to include this piece of equipment would be advised and if it is possible
to remove the controller without affecting the operational capacity of the system, however the
manufacturers Turbotricity have closed down since the system was purchased and the
technician responsible for sourcing and installing the system is not an employee of LIT
anymore. So due to the fact that little or no information is available with regards to the role of
the controller it is advisable not to remove from the system as it may cause unforeseen
problems to the system.
With regards to braking mechanism employed a variable resistive load could be used to slowly
increase the resistive load and thus bringing the rotor and the rotor blades to a gradual stop
instead of a sudden stop. However these variable resistor are expensive and as the system
has a very smallenergy output it is not financially feasible to do sounless it was for educational
or demonstration purposes.
Regards the safety issue of the brake switch it is recommended that a sign be erected directly
beside the switch stating its exact purpose as to differentiate it from the two electrical isolation
switches.
The calibration of the Anemometer is probably twice the range of what it needs to be, a 0-
30m/s calibration would be sufficient and would also increase the accuracy of the
measurements as the range is reduced by half.
Also it cannot be overstated the importance of establishing communications between devices
at the initial stage of the project, it is recommended that all methods of communication be
tested as early as possible that way if one method of communications fail another method can
be used without the loss of time.

59
Overall the system is inefficient especially considering the location is far from ideal as it is
surrounded by building which creates turbulence and a reduction in available wind energy and
as a result will never produce enough energy to even come near to repaying the initial cost of
the system but as a demonstration model this student found the experience and knowledge
gained during the course of the project invaluable and as a teaching aid the system may have
an important role for future students also.

60
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64
9 Appendices
9.1 Appendix A: Data sheet Aurora PVI 3600
9.2 Appendix B: Data sheet Aurora PVI 7200

65
9.3 Appendix C: Data sheet WMT52
9.4 Appendix D: Data sheet V200-18-E3XB

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