Residential grid connected PV system.
ii
RESIDENTIAL GRID-CONNECTED PV SYSTEM
MOHAMAD NAZRI BIN MOHAMAD DIN
A report submitted in partial fulfillment of the requirement for the degree of
Bachelor of Electrical Engineering (Control, Instrumentation and Automation)
Faculty of Electrical Engineering
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
2014
iii
I hereby declare that I have read through this report entitle "Residential Grid Connected
PV System" and found that it has comply the partial fulfillment for awarding the degree
of Bachelor of Electrical Engineering (Control, Instrumentation and Automation).
........
ｾ＠
...................... .
Signature
:
Name
: Ｎｾ＠
Date
r1 'J0J1 ｾ＠
i w.
: ............................... i ........................ .
.....g90. ... ｾＮＧ＠
.....ｾＧＮ＠
............. .
iv
I declare that this report "Residential Grid-Connected PV System" is the result of my
own research except as cited in the references. The report has not been accepted for any
degree and is not concurrently submitted candidature of any other degree.
Signature
:
ﾷＭｾ＠
Name
Date
:...'.1...＿ＮｾＺ＠
..... ｾＮｪﾷ＠
v
ACKNOWLEDGEMENT
I am grateful and would like to express my sincere gratitude to my
supervisor Dr Gan Chin Kim for this invaluable guidance, continuous
encouragement and constant support in making this research possible. I really
appreciate his guidance from the initial to the final level that enabled me to
develop an understanding of this project thoroughly. Without his advice and
assistance it would be lot tougher to complete. I also sincerely thanks for the time
spent and correcting my mistakes. My sincere thanks go to all lectures and
member of the staff of the Electrical Engineering Department, UTeM who helped
me in many ways and made my education journey at UTeM pleasant and
unforgettable. Many thanks go to all classmates for their excellent co-operation,
inspirations and support during this study. I acknowledge my sincere indebtedness
and gratitude to my parents for their love, dream and sacrifice throughout my
life.I am really thankful for their sacrifice; patience and understanding that were
inevitable to make this work possible. Their sacrifice had inspired from the day I
learned how to read and write until what I become now. I cannot find appropriate
would properly describe my appreciation for their devotion; lastly I would like to
acknowledge their comments and suggestions, which was crucial for the
successful competition of this study.
vi
ABSTRACT
Generating electric by using renewable energy such as solar energy, wind
energy and geothermal energy is a good move because it can reduce the emission
of carbon dioxide. Nowadays, the price of electric is increase due to the
increasing of oil price. The price of electric will continue to increase because the
oil is decreasing due to always being used in daily activities .To cope with the
increase in electricity prices, this study has made to help the public to generate
their own electricity. The purpose of this study is to design a 4 kW residential
grid- connected PV system on the rooftop and to analyses the performance of the
system. In order to achieve that the type of solar module, tilt angle and the
function of related component such as inverter, AC distribution board and
metering need to be identify. The main result for this project is the drawing of the
4 kW grid connected PV system which is suitable for the selected house. At the
end of this project, a comprehensive report about analysis and discussion made
based on the results obtained is produced.
vii
ABSTRAK
Menjana elektrik dengan menggunakan tenaga boleh diperbaharui seperti
tenaga solar, tenaga angin dan tenaga geoterma adalah satu langkah yang baik
kerana ia boleh mengurangkan pelepasan karbon dioksida. Pada masa kini , harga
elektrik semakin meningkatan disebabkan oleh peningkatan harga minyak. Harga
elektrik akan terns meningkat kerana minyak semakin berkurangan kerana
sentiasa digunakan dalam aktiviti harian. Untuk mengatasi peningkatan harga
elektrik, kajian ini telah dibuat bagi membantu orang awam supaya dapat menjana
elektrik mereka sendiri . Tujuan kajian ini ialah mereka bentuk 4 kW kediaman
grid yang berkaitan sistem PV di atas bumbung serta menganalisis prestasi sistem
.Dalam usaha untuk mencapai sasaran ,jenis modul solar, sudut kecondongan dan
fungsi komponen yang berkaitan seperti penyongsang , AC papan agihan dan
pemeteran perlu dikenal pasti. Keputusan utama bagi projek ini adalah lukisan
daripada 4 KWP grid berkaitan sistem PV yang sesuai untuk rumah yang dipilih.
Pada akhir projek ini, satu laporan komprehensif tentang analisis dan
perbincangan dibuat berdasarkan keputusan yang diperolehi .
viii
TABLE OF CONTENTS
CHAPTER
1
TITLE
ACKNOLEDGEMENT
ABSTRACT
TABLE OF CONTENTS
LIST OF TABLES
LIST OF FIGURES
Vl
Vlll
x
Xl
INTRODUCTION
1.1.1
Project Background
1
1.1.2
Grid -Connected solar PV System
1
1.1.3
Central System
2
1.1.4
Distributed System
3
1.2
Project Motivation
5
1.3
Project Statement
5
1.4
Objectives
6
Scope of Research
6
1.5
2
PAGE
v
Report outlines
7
LITERATURE RIVIEW
2.1
Overview of Solar PV System
8
2.1.1
Solar Radiation
8
2.1.1.1
Inadiance
8
2.1.1.2
Geometric Effect
9
2.1.2
PV cells
10
2.1.2.l
Atomic Structure of Silicon
10
ix
2.2
2.3
3
2.1.3
Solar PV module
11
2.1.3.1
Cell Connection
11
2.1.3.2
Bypass Diode
13
2.1.4
Inverter
14
2.1.5
Distribution Board
17
Related Previous Work
18
2.2.1
Research by R. N. S. R. Mukhtarnddin
18
2.2.2
Research by Joachim Seel and Galen
19
2.2.3
Research by Sujit Kumar
20
2.2.4
Research by T. Shimada, K. Kurokawa
21
2.2.5
Research by Benz Croxford and Kat Scott
22
2.2.6
Research by Adel El-Menchaw
23
Summary of Review
25
DESIGN METHODOLOGY
3 .I
Project Methodology
26
3.1.1
Gant chart and flowchart
26
3.1.2
Location of System Equipment
28
3.1.3
Determine the Total Number of Modules that
can fit The Roof
28
3.1.4
The Tilt Angle
30
3.1.5
Selection oflnverter
31
3.1.6
Power losses in Grid Connected PV System
31
3.1.7
Matching the PV array to Voltage Specification
of an Inverter
33
3.1.8
Matching the PV arrays Power Output to the .
Inverters Power Rating
34
3.1.9
Protection Equipment and Switching
34
3.1.10
Lightning Protection
35
3.1.11
Interconnecting the System to Gtid
36
3.1.12
Drawing
36
x
3 .2
Approach
3.2. l
4
37
RESULT AND DISCUSSION
4.1
4.2
5
Case Study
37
Result and Discussion
38
4.1.1
Efficiency of Module
38
4.1.2
The Total Number of Module that Used
40
4.1.3
Solar Module Orientation
42
4.1.4
The Tilt Angle
42
4.1.5
Selection of Inverter
42
4.1.6
Power Losses in Grid Connected System
46
4.1.7
Matching the PY Array
50
4.1.8
Matching the PY A1nys Power Output
51
4.1.9
Protection Equipment and Switching
51
4.1.10
Lightning Protection
52
4.1.11
Interconnection to the G1id
53
4.1.12
Drawing of Grid connected PY system
53
57
Return on Residential Solar PY Investment
CONCLUSION AND RECOMMENDATION
59
REFERENCE
61
63
APPENDIX
xi
LIST OF TABLE
Table 1: Summary of solar parameters
8
Table 2: The limit of distortion of odd harmonic and even harmonic
15
Table 3: Maximum trip time of voltage fluctuation test
16
Table 4: Payback for reducing carbon dioxide (30 years
23
Table 5: The price for 1 kWh by using photovoltaic panels and a diesel generator
24
Table 6: The installation price for PV systems
37
Table 7: Conversion efficiency of module
38
Table 8: Type of solar module and its criteria
39
Table 9: The characteristics of inverter
43
Table lO:The differences of string inverter
44
Tablell : Main installation checklist
56
Table 12 : Solar PV fit rates for Malaysia
57
xii
LIST OF FIGURE
Figure 1: Grid-connected solar PV system configuration
2
Figure 2: Rembia World Solar Valley 5MWp central PV system
3
Figure 3: Kumpulan Melaka Berhad lOkWp commercial PV system
4
Figure 4: Rooftop 2kWp (Germany) domestic PV system
4
Figure 5: Effect of varying tilt angles on solar capture
9
Figure 6: Placement of solar module in relation to Sun's altitude
9
Figure 7: Atomic structure of silicon
10
Figure 8: The photoelectric effect
11
Figure 9: The IV characteristic of single module
12
Figure 9.1: The IV characteristic ofcombined cells (identical cells)
12
Figure 10: The IV characteristic of dissimilar cells
12
Figure 10.1: The combination IVcharacteristicc betweendissimilarr cells
13
Figure 11: Schematic diagram of bypass diode
13
Figure 12: Photo of bypass diode in actual module junction box
14
Figure 13: Small inverter in solar field
14
Figure 14: Ac distribution board
17
Figure 15: System configuration
21
xiii
Figure 16: List of project activity
26
Figure 17: Flowchart of the project
27
Figure 18: location of the system equipment
28
Figure 19: Schematic diagram of grid connected PV system
35
Figure 20: Procedure for applying interconnection to grid
36
Figure 21: Block and single diagram for grid connected system
37
Figure 22: Block and single diagram
47
Figure 23: Solar module Orientation
54
Figure 24: Schematic diagram of a 4 kW Residential Grid Connected PV system
Figure 25: The position of solar module according to the sun
54
60
1
CHAPTER!
INTRODUCTION
1.1.l
Project Background
By using the sun as the source of energy, there are several types of solar power
systems but there are two systems that commonly used. There are solar thermal systems and
solar PV systems. Solar thermal systems absorb heat to warm up water while solar PV
systems using sunlight to generate electricity. The main advantages for using renewable
system are they can save energy (generate profit) and reduce environmental pollution.
[l]Solar PV systems have two main types: grid-connected and off-grid solar PV system. This
research will explain about the design of grid-connected PV system.
1.1.2
Grid -Connected Solar PV System
Figure 1 below show an example of grid connected PV system and the component
that need to be considered before making a design .There are two parallel power supplies for
building which is from power grid and from solar PV system. These two power supply were
combined to feeds all the loads that connected to the main AC distribution board.
2
Panel
Data
Module
Com munic.adon
tnvener
AC
Board
Substation
Supply from
Power Grid
Figure 1: Grid-connected PV system configuration
The size of solar PV system will determine the ratio of solar PV supply to the power
grid supply. If there is excess electricity, it will be exported into the grid. When there is a
storm, rain or at night which means the solar module cannot generate electricity, building
demand will be supplied by the power grid. [2]As we know, the grid connected PV system
generates direct current by using sunlight. This direct current was converted to alternating
current by using the inverter and supplied into the grid. Grid-connected PV system is divided
by two which are central system and distributed system (residential). [3]
1.1.3
Central System
A central grid-connected PV system operates similarly. For the central system, it
usually uses a lot of space because its produce large energy. Figure 2 shows the project of
solar PV systems at Rembia World Solar Valley recently completed in September 2013. This
project is the largest solar PV central system in Malaysia so far.
3
Figure 2: Rembia World Solar Valley 5MWp central PV system
1.1.4
Distributed System
There are two types of distributed system: commercial and domestic. Commercial
system is usually greater than 1OkWp and commonly used for building. The power generated
by distributed systems is consumed by the loads within the building and no power exported
to the electricity grid. The domestic system range is lower than 10 kW (usually between 1 to
5 kW) and is suitable to be installed on the roof of the house. Domestic system will generate
electric power and will be used by the operating load at home. The excess power generators
by these systems will be fed into the grid. Then it will provide the power to nearby houses
and the owner will get profit from it. [4] Figure 3 and 4 shows the example of the domestic
system which located in Melaka and Germany.
4
Figure 3: Kumpulan Melaka Berhad 1OkWp commercial PV system
Figure 4: Rooftop 2kWp domestic PV system.
5
1.2
Project Motivation
Renewable energy has several advantages such as energy security, income for owner,
energy for future generation and increase environments and human health. By using
renewable energy, our country's energy security problem can be solved because we no longer
depend on fossil fuel. According to Bonnie Raitt, "Promoting renewable energy is the most
patriotic act we can commit. It makes our country less dependent on foreign oil and less
likely to go to war." In addition, it also gives monthly income to the owner for long period of
time. Renewable energy sources also replenished. This means if we using renewable energy
system, so it will not only benefits us now, but will also benefits to the generation after us.
Besides that, it also friendlier to the environment compare to the fossil fuel system. As we
know, fossil fuels contribute to many environmental issue that we face today such as
greenhouse gases, air pollution and soil contamination. The problem above will lead to
global warming. Fortunately, renewable energy system will reduce the emission of carbon
dioxide and make our environment clean.
1.3
Project Statement
Nowadays, electricity is the most important to our life because it does so many jobs
for us. Without electricity, we can't use televisions, computers, refrigerators and other things.
We also wouldn't be able to see at night if we do not have electricity. Try to imagine if we
had to live without electricity for one month? What will happen to us?. Every year the price
for electricity is rising due to the demands, why not we generate our electricity. According to
Tenaga National (http://www.tnb.com.my/residential/pricing-and-tariff.html), they have
6
raised the tariff for electricity (7.12 % ) since 1st June 2011 because of the price of oil rises.
All the information regarding new tariff is displayed in the Tenaga National website.
For that reason, the government has already introduced the renewable energy such as
solar energy, wind energy and geothermal energy. For housing, we can generate electricity
by using solar PV systems. Actually, Malaysia is vety suitable for solar PV system because
the weather is hot and dty throughout the year. However most people do not know about the
solar PV systems and makes them lost interest in this system. To overcome the problem of
rising electricity prices, the solar PV system is the best solution because its give long term
profit and reduce pollution.
1.4
Objectives
a) To identify the function of related component such as inverter, AC distribution
board and metering.
b) To design a 4 kWp residential grid-connected PV system on the rooftop.
c) To determine the return of investment of 4kWp residential grid connected PV
system.
Scope of Research
a) Determine the total solar module that can be installed on the roof.
b) Design a 4 kWp residential grid connected PV system on the rooftop.
c) Determine the type of solar module and tilt angle.
d) To identify the function of related component such as inverter, AC distribution
board and metering.
7
e) Another aspect such as the construction of solar panels and the factors that affect
the performance of the PV system will not be covered in this report.
1.5
Report Outlines
This progress report consists of five chapters. In the first chapter, it will focus on the
background, scope of the project, objective and the problem statement.
In Chapter 2,
literature review of the project is will be briefly explained. In this chapter, it will focus on
the explanation of the related component for design a grid-connected PV system such as PV
cells, solar module, inverter and distribution board.
Chapter 3 will be focusing on how to calculate the total solar module that used, the
tilt angle of solar module and the design of grid connected PV system. This chapter also
explains the simulation of the project. The result and discussion are presented and discussed
in the Chapter 4. All the output obtained from the simulation process are analyzed and
discussed.
Finally Chapter 5 will discuss the recommendation for future work and
conclusion of this project was given and provided.
8
CHAPTER2
LITERATURE REVIEW
2.1
Overview of Solar PV System
2.1.1
Solar Radiation
2.1.1.1 Irradiance
Solar constant can be defined as the energy from the sun that arrive in the earth's
atmosphere at peak value of 1367 kWm-2 while the ordinance is total of solar power available
per unit area. [5] A summary of the solar parameters is listed in table 1.
Table 1: Summary of solar parameters
Parameter
Irradiance
Measuring devises
Solar constant
Peak value at sea
level
Nominal value
Symbol
G
Pyranometer (thermopile or
reference solar PV cells)
Gas
Go
-
Quantity and unit
kWm-.l, Wm-.l, mWcm-.l
-
1.367 kwm-.l
lkWm-.l, 1000 Wm-.l,
lOOmWcm-2
0.8kwm-1 , 800 wm-1 ,
80mWcm-2
9
2.1.1.2 Geometric Effect
The sun altitude angle ex is veiy important to make sure the module collects all
incoming 12 rays from the sun. If the module is placed without the sun altitude angle ex, it
only can collect 9 rays and the output cannot reach the maximum. This theory can be seen in
Figure 5. The module will face either north or south depending the location of the
khatulistiwa. At noon, the position of the module will be 90 degrees to the sun as shown in
Figure 6 to make sure the module can generate maximum output. [5]
Incoming 12 rays from the sun
ｾ＠
Collect 12 ravs
Sun's altitude
angle a
Figure 5: Effect of varying tilt angles on solar capture
Tilt angle
Ofmodule
6
Altitude of the sun a
Figure 6: Placement of solar module in relation to Sun's altitude.
J
10
2.1.2
PV cells
2.1.2.1 Atomic Structure of Silicon
Silicon made up from:
•
Photons (positive charge)
•
Neutrons (neutral charge)
•
Electrons (negative charge)
2 electrons in
first shell
4 electrons in
- - - - - - - - - - - third shell
8 efectrons in
second shell
Figure 7: Atomic structure of silicon
The first shell of the Sillicon as shown in Figure 7 only can store 2 electrons and
second shell can store 8 electrons. Since it's already filled up, it cannot take any electrons.
Besides, they are tightly bound to nucleus so they cannot become free electrons. However the
third shell is not completely filled with the electrons. There are 4 electrons that needed in
order to form complete bonding. The electrons in the third shell will become free electrons if
they receive the energy that equal or larger than the energy binding provide by the silicon. [6]
Figure 8 will shows us the process for photoelectric effect in order to become free electron.
11
J-
Incoming ｰｨｯｴｮｾ＠
/
.(/
•
Ｇｾ＠
Hole left after the electron
has been ejected
•
Before collision of the photon
with the electron
After the collision the silicon atom has a
net positive charge and has lost one of
its electrons
Figure 8: The photoelectric effect
2.1.3
Solar PV module
Solar PV module made up from the combination of identical cells and produce an
open circuit voltage greater or equal to 20V. It's also suitable for charging a 12V battery.
2.1.3.1 Cell Connection
If the cell is combined together with two or more identical in series, the voltage will
increase while the current remains the same.This idea can be visualised in Figure 9 and 9.1.
12
4
0.6
Figure 9: The IV characteristic of single module
volt: age
1.8
Figure 9.1: The IV characteristic ofcombined cells (identical cells)
The voltage will remain the same if the dissimilar cells are combined together but the
current will follow the smaller value of the cells. [7] This idea can be visualised in Figure 10
and 10.1
4
0.6
Figure 10: The IV characteristic of dissimilar cells
0.6
RESIDENTIAL GRID-CONNECTED PV SYSTEM
MOHAMAD NAZRI BIN MOHAMAD DIN
A report submitted in partial fulfillment of the requirement for the degree of
Bachelor of Electrical Engineering (Control, Instrumentation and Automation)
Faculty of Electrical Engineering
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
2014
iii
I hereby declare that I have read through this report entitle "Residential Grid Connected
PV System" and found that it has comply the partial fulfillment for awarding the degree
of Bachelor of Electrical Engineering (Control, Instrumentation and Automation).
........
ｾ＠
...................... .
Signature
:
Name
: Ｎｾ＠
Date
r1 'J0J1 ｾ＠
i w.
: ............................... i ........................ .
.....g90. ... ｾＮＧ＠
.....ｾＧＮ＠
............. .
iv
I declare that this report "Residential Grid-Connected PV System" is the result of my
own research except as cited in the references. The report has not been accepted for any
degree and is not concurrently submitted candidature of any other degree.
Signature
:
ﾷＭｾ＠
Name
Date
:...'.1...＿ＮｾＺ＠
..... ｾＮｪﾷ＠
v
ACKNOWLEDGEMENT
I am grateful and would like to express my sincere gratitude to my
supervisor Dr Gan Chin Kim for this invaluable guidance, continuous
encouragement and constant support in making this research possible. I really
appreciate his guidance from the initial to the final level that enabled me to
develop an understanding of this project thoroughly. Without his advice and
assistance it would be lot tougher to complete. I also sincerely thanks for the time
spent and correcting my mistakes. My sincere thanks go to all lectures and
member of the staff of the Electrical Engineering Department, UTeM who helped
me in many ways and made my education journey at UTeM pleasant and
unforgettable. Many thanks go to all classmates for their excellent co-operation,
inspirations and support during this study. I acknowledge my sincere indebtedness
and gratitude to my parents for their love, dream and sacrifice throughout my
life.I am really thankful for their sacrifice; patience and understanding that were
inevitable to make this work possible. Their sacrifice had inspired from the day I
learned how to read and write until what I become now. I cannot find appropriate
would properly describe my appreciation for their devotion; lastly I would like to
acknowledge their comments and suggestions, which was crucial for the
successful competition of this study.
vi
ABSTRACT
Generating electric by using renewable energy such as solar energy, wind
energy and geothermal energy is a good move because it can reduce the emission
of carbon dioxide. Nowadays, the price of electric is increase due to the
increasing of oil price. The price of electric will continue to increase because the
oil is decreasing due to always being used in daily activities .To cope with the
increase in electricity prices, this study has made to help the public to generate
their own electricity. The purpose of this study is to design a 4 kW residential
grid- connected PV system on the rooftop and to analyses the performance of the
system. In order to achieve that the type of solar module, tilt angle and the
function of related component such as inverter, AC distribution board and
metering need to be identify. The main result for this project is the drawing of the
4 kW grid connected PV system which is suitable for the selected house. At the
end of this project, a comprehensive report about analysis and discussion made
based on the results obtained is produced.
vii
ABSTRAK
Menjana elektrik dengan menggunakan tenaga boleh diperbaharui seperti
tenaga solar, tenaga angin dan tenaga geoterma adalah satu langkah yang baik
kerana ia boleh mengurangkan pelepasan karbon dioksida. Pada masa kini , harga
elektrik semakin meningkatan disebabkan oleh peningkatan harga minyak. Harga
elektrik akan terns meningkat kerana minyak semakin berkurangan kerana
sentiasa digunakan dalam aktiviti harian. Untuk mengatasi peningkatan harga
elektrik, kajian ini telah dibuat bagi membantu orang awam supaya dapat menjana
elektrik mereka sendiri . Tujuan kajian ini ialah mereka bentuk 4 kW kediaman
grid yang berkaitan sistem PV di atas bumbung serta menganalisis prestasi sistem
.Dalam usaha untuk mencapai sasaran ,jenis modul solar, sudut kecondongan dan
fungsi komponen yang berkaitan seperti penyongsang , AC papan agihan dan
pemeteran perlu dikenal pasti. Keputusan utama bagi projek ini adalah lukisan
daripada 4 KWP grid berkaitan sistem PV yang sesuai untuk rumah yang dipilih.
Pada akhir projek ini, satu laporan komprehensif tentang analisis dan
perbincangan dibuat berdasarkan keputusan yang diperolehi .
viii
TABLE OF CONTENTS
CHAPTER
1
TITLE
ACKNOLEDGEMENT
ABSTRACT
TABLE OF CONTENTS
LIST OF TABLES
LIST OF FIGURES
Vl
Vlll
x
Xl
INTRODUCTION
1.1.1
Project Background
1
1.1.2
Grid -Connected solar PV System
1
1.1.3
Central System
2
1.1.4
Distributed System
3
1.2
Project Motivation
5
1.3
Project Statement
5
1.4
Objectives
6
Scope of Research
6
1.5
2
PAGE
v
Report outlines
7
LITERATURE RIVIEW
2.1
Overview of Solar PV System
8
2.1.1
Solar Radiation
8
2.1.1.1
Inadiance
8
2.1.1.2
Geometric Effect
9
2.1.2
PV cells
10
2.1.2.l
Atomic Structure of Silicon
10
ix
2.2
2.3
3
2.1.3
Solar PV module
11
2.1.3.1
Cell Connection
11
2.1.3.2
Bypass Diode
13
2.1.4
Inverter
14
2.1.5
Distribution Board
17
Related Previous Work
18
2.2.1
Research by R. N. S. R. Mukhtarnddin
18
2.2.2
Research by Joachim Seel and Galen
19
2.2.3
Research by Sujit Kumar
20
2.2.4
Research by T. Shimada, K. Kurokawa
21
2.2.5
Research by Benz Croxford and Kat Scott
22
2.2.6
Research by Adel El-Menchaw
23
Summary of Review
25
DESIGN METHODOLOGY
3 .I
Project Methodology
26
3.1.1
Gant chart and flowchart
26
3.1.2
Location of System Equipment
28
3.1.3
Determine the Total Number of Modules that
can fit The Roof
28
3.1.4
The Tilt Angle
30
3.1.5
Selection oflnverter
31
3.1.6
Power losses in Grid Connected PV System
31
3.1.7
Matching the PV array to Voltage Specification
of an Inverter
33
3.1.8
Matching the PV arrays Power Output to the .
Inverters Power Rating
34
3.1.9
Protection Equipment and Switching
34
3.1.10
Lightning Protection
35
3.1.11
Interconnecting the System to Gtid
36
3.1.12
Drawing
36
x
3 .2
Approach
3.2. l
4
37
RESULT AND DISCUSSION
4.1
4.2
5
Case Study
37
Result and Discussion
38
4.1.1
Efficiency of Module
38
4.1.2
The Total Number of Module that Used
40
4.1.3
Solar Module Orientation
42
4.1.4
The Tilt Angle
42
4.1.5
Selection of Inverter
42
4.1.6
Power Losses in Grid Connected System
46
4.1.7
Matching the PY Array
50
4.1.8
Matching the PY A1nys Power Output
51
4.1.9
Protection Equipment and Switching
51
4.1.10
Lightning Protection
52
4.1.11
Interconnection to the G1id
53
4.1.12
Drawing of Grid connected PY system
53
57
Return on Residential Solar PY Investment
CONCLUSION AND RECOMMENDATION
59
REFERENCE
61
63
APPENDIX
xi
LIST OF TABLE
Table 1: Summary of solar parameters
8
Table 2: The limit of distortion of odd harmonic and even harmonic
15
Table 3: Maximum trip time of voltage fluctuation test
16
Table 4: Payback for reducing carbon dioxide (30 years
23
Table 5: The price for 1 kWh by using photovoltaic panels and a diesel generator
24
Table 6: The installation price for PV systems
37
Table 7: Conversion efficiency of module
38
Table 8: Type of solar module and its criteria
39
Table 9: The characteristics of inverter
43
Table lO:The differences of string inverter
44
Tablell : Main installation checklist
56
Table 12 : Solar PV fit rates for Malaysia
57
xii
LIST OF FIGURE
Figure 1: Grid-connected solar PV system configuration
2
Figure 2: Rembia World Solar Valley 5MWp central PV system
3
Figure 3: Kumpulan Melaka Berhad lOkWp commercial PV system
4
Figure 4: Rooftop 2kWp (Germany) domestic PV system
4
Figure 5: Effect of varying tilt angles on solar capture
9
Figure 6: Placement of solar module in relation to Sun's altitude
9
Figure 7: Atomic structure of silicon
10
Figure 8: The photoelectric effect
11
Figure 9: The IV characteristic of single module
12
Figure 9.1: The IV characteristic ofcombined cells (identical cells)
12
Figure 10: The IV characteristic of dissimilar cells
12
Figure 10.1: The combination IVcharacteristicc betweendissimilarr cells
13
Figure 11: Schematic diagram of bypass diode
13
Figure 12: Photo of bypass diode in actual module junction box
14
Figure 13: Small inverter in solar field
14
Figure 14: Ac distribution board
17
Figure 15: System configuration
21
xiii
Figure 16: List of project activity
26
Figure 17: Flowchart of the project
27
Figure 18: location of the system equipment
28
Figure 19: Schematic diagram of grid connected PV system
35
Figure 20: Procedure for applying interconnection to grid
36
Figure 21: Block and single diagram for grid connected system
37
Figure 22: Block and single diagram
47
Figure 23: Solar module Orientation
54
Figure 24: Schematic diagram of a 4 kW Residential Grid Connected PV system
Figure 25: The position of solar module according to the sun
54
60
1
CHAPTER!
INTRODUCTION
1.1.l
Project Background
By using the sun as the source of energy, there are several types of solar power
systems but there are two systems that commonly used. There are solar thermal systems and
solar PV systems. Solar thermal systems absorb heat to warm up water while solar PV
systems using sunlight to generate electricity. The main advantages for using renewable
system are they can save energy (generate profit) and reduce environmental pollution.
[l]Solar PV systems have two main types: grid-connected and off-grid solar PV system. This
research will explain about the design of grid-connected PV system.
1.1.2
Grid -Connected Solar PV System
Figure 1 below show an example of grid connected PV system and the component
that need to be considered before making a design .There are two parallel power supplies for
building which is from power grid and from solar PV system. These two power supply were
combined to feeds all the loads that connected to the main AC distribution board.
2
Panel
Data
Module
Com munic.adon
tnvener
AC
Board
Substation
Supply from
Power Grid
Figure 1: Grid-connected PV system configuration
The size of solar PV system will determine the ratio of solar PV supply to the power
grid supply. If there is excess electricity, it will be exported into the grid. When there is a
storm, rain or at night which means the solar module cannot generate electricity, building
demand will be supplied by the power grid. [2]As we know, the grid connected PV system
generates direct current by using sunlight. This direct current was converted to alternating
current by using the inverter and supplied into the grid. Grid-connected PV system is divided
by two which are central system and distributed system (residential). [3]
1.1.3
Central System
A central grid-connected PV system operates similarly. For the central system, it
usually uses a lot of space because its produce large energy. Figure 2 shows the project of
solar PV systems at Rembia World Solar Valley recently completed in September 2013. This
project is the largest solar PV central system in Malaysia so far.
3
Figure 2: Rembia World Solar Valley 5MWp central PV system
1.1.4
Distributed System
There are two types of distributed system: commercial and domestic. Commercial
system is usually greater than 1OkWp and commonly used for building. The power generated
by distributed systems is consumed by the loads within the building and no power exported
to the electricity grid. The domestic system range is lower than 10 kW (usually between 1 to
5 kW) and is suitable to be installed on the roof of the house. Domestic system will generate
electric power and will be used by the operating load at home. The excess power generators
by these systems will be fed into the grid. Then it will provide the power to nearby houses
and the owner will get profit from it. [4] Figure 3 and 4 shows the example of the domestic
system which located in Melaka and Germany.
4
Figure 3: Kumpulan Melaka Berhad 1OkWp commercial PV system
Figure 4: Rooftop 2kWp domestic PV system.
5
1.2
Project Motivation
Renewable energy has several advantages such as energy security, income for owner,
energy for future generation and increase environments and human health. By using
renewable energy, our country's energy security problem can be solved because we no longer
depend on fossil fuel. According to Bonnie Raitt, "Promoting renewable energy is the most
patriotic act we can commit. It makes our country less dependent on foreign oil and less
likely to go to war." In addition, it also gives monthly income to the owner for long period of
time. Renewable energy sources also replenished. This means if we using renewable energy
system, so it will not only benefits us now, but will also benefits to the generation after us.
Besides that, it also friendlier to the environment compare to the fossil fuel system. As we
know, fossil fuels contribute to many environmental issue that we face today such as
greenhouse gases, air pollution and soil contamination. The problem above will lead to
global warming. Fortunately, renewable energy system will reduce the emission of carbon
dioxide and make our environment clean.
1.3
Project Statement
Nowadays, electricity is the most important to our life because it does so many jobs
for us. Without electricity, we can't use televisions, computers, refrigerators and other things.
We also wouldn't be able to see at night if we do not have electricity. Try to imagine if we
had to live without electricity for one month? What will happen to us?. Every year the price
for electricity is rising due to the demands, why not we generate our electricity. According to
Tenaga National (http://www.tnb.com.my/residential/pricing-and-tariff.html), they have
6
raised the tariff for electricity (7.12 % ) since 1st June 2011 because of the price of oil rises.
All the information regarding new tariff is displayed in the Tenaga National website.
For that reason, the government has already introduced the renewable energy such as
solar energy, wind energy and geothermal energy. For housing, we can generate electricity
by using solar PV systems. Actually, Malaysia is vety suitable for solar PV system because
the weather is hot and dty throughout the year. However most people do not know about the
solar PV systems and makes them lost interest in this system. To overcome the problem of
rising electricity prices, the solar PV system is the best solution because its give long term
profit and reduce pollution.
1.4
Objectives
a) To identify the function of related component such as inverter, AC distribution
board and metering.
b) To design a 4 kWp residential grid-connected PV system on the rooftop.
c) To determine the return of investment of 4kWp residential grid connected PV
system.
Scope of Research
a) Determine the total solar module that can be installed on the roof.
b) Design a 4 kWp residential grid connected PV system on the rooftop.
c) Determine the type of solar module and tilt angle.
d) To identify the function of related component such as inverter, AC distribution
board and metering.
7
e) Another aspect such as the construction of solar panels and the factors that affect
the performance of the PV system will not be covered in this report.
1.5
Report Outlines
This progress report consists of five chapters. In the first chapter, it will focus on the
background, scope of the project, objective and the problem statement.
In Chapter 2,
literature review of the project is will be briefly explained. In this chapter, it will focus on
the explanation of the related component for design a grid-connected PV system such as PV
cells, solar module, inverter and distribution board.
Chapter 3 will be focusing on how to calculate the total solar module that used, the
tilt angle of solar module and the design of grid connected PV system. This chapter also
explains the simulation of the project. The result and discussion are presented and discussed
in the Chapter 4. All the output obtained from the simulation process are analyzed and
discussed.
Finally Chapter 5 will discuss the recommendation for future work and
conclusion of this project was given and provided.
8
CHAPTER2
LITERATURE REVIEW
2.1
Overview of Solar PV System
2.1.1
Solar Radiation
2.1.1.1 Irradiance
Solar constant can be defined as the energy from the sun that arrive in the earth's
atmosphere at peak value of 1367 kWm-2 while the ordinance is total of solar power available
per unit area. [5] A summary of the solar parameters is listed in table 1.
Table 1: Summary of solar parameters
Parameter
Irradiance
Measuring devises
Solar constant
Peak value at sea
level
Nominal value
Symbol
G
Pyranometer (thermopile or
reference solar PV cells)
Gas
Go
-
Quantity and unit
kWm-.l, Wm-.l, mWcm-.l
-
1.367 kwm-.l
lkWm-.l, 1000 Wm-.l,
lOOmWcm-2
0.8kwm-1 , 800 wm-1 ,
80mWcm-2
9
2.1.1.2 Geometric Effect
The sun altitude angle ex is veiy important to make sure the module collects all
incoming 12 rays from the sun. If the module is placed without the sun altitude angle ex, it
only can collect 9 rays and the output cannot reach the maximum. This theory can be seen in
Figure 5. The module will face either north or south depending the location of the
khatulistiwa. At noon, the position of the module will be 90 degrees to the sun as shown in
Figure 6 to make sure the module can generate maximum output. [5]
Incoming 12 rays from the sun
ｾ＠
Collect 12 ravs
Sun's altitude
angle a
Figure 5: Effect of varying tilt angles on solar capture
Tilt angle
Ofmodule
6
Altitude of the sun a
Figure 6: Placement of solar module in relation to Sun's altitude.
J
10
2.1.2
PV cells
2.1.2.1 Atomic Structure of Silicon
Silicon made up from:
•
Photons (positive charge)
•
Neutrons (neutral charge)
•
Electrons (negative charge)
2 electrons in
first shell
4 electrons in
- - - - - - - - - - - third shell
8 efectrons in
second shell
Figure 7: Atomic structure of silicon
The first shell of the Sillicon as shown in Figure 7 only can store 2 electrons and
second shell can store 8 electrons. Since it's already filled up, it cannot take any electrons.
Besides, they are tightly bound to nucleus so they cannot become free electrons. However the
third shell is not completely filled with the electrons. There are 4 electrons that needed in
order to form complete bonding. The electrons in the third shell will become free electrons if
they receive the energy that equal or larger than the energy binding provide by the silicon. [6]
Figure 8 will shows us the process for photoelectric effect in order to become free electron.
11
J-
Incoming ｰｨｯｴｮｾ＠
/
.(/
•
Ｇｾ＠
Hole left after the electron
has been ejected
•
Before collision of the photon
with the electron
After the collision the silicon atom has a
net positive charge and has lost one of
its electrons
Figure 8: The photoelectric effect
2.1.3
Solar PV module
Solar PV module made up from the combination of identical cells and produce an
open circuit voltage greater or equal to 20V. It's also suitable for charging a 12V battery.
2.1.3.1 Cell Connection
If the cell is combined together with two or more identical in series, the voltage will
increase while the current remains the same.This idea can be visualised in Figure 9 and 9.1.
12
4
0.6
Figure 9: The IV characteristic of single module
volt: age
1.8
Figure 9.1: The IV characteristic ofcombined cells (identical cells)
The voltage will remain the same if the dissimilar cells are combined together but the
current will follow the smaller value of the cells. [7] This idea can be visualised in Figure 10
and 10.1
4
0.6
Figure 10: The IV characteristic of dissimilar cells
0.6