An-Najah National University 

Faculty of Graduate Studies 

 

 

 

PV-GRID CONNECTED POWER SYSTEM TO 

TUBAS ELECTRIC NETWORK (TDECO): FIELD 

TESTS, EVALUATION AND OPTIMIZATION. 

 

 

 

By 

 Ishraq Serhan Jarrar 

 

Supervisor 

 Prof. Dr. Marwan Mahmoud 

 

 

This Thesis is submitted in Partial Fulfillment of the Requirements for 

the Degree of Master of Clean Energy and Conservation Strategy 

Engineering, Faculty of Graduate Studies, An-Najah National 

University, Nablus, Palestine. 

2018 



II 
 

 

 

 

 
 

 

 
 

PV-GRID CONNECTED POWER SYSTEM TO 

TUBAS ELECTRIC NETWORK (TDECO): FIELD 

TESTS, EVALUATION, AND OPTIMIZATION. 

 

 
 

By 

Ishraq Serhan Jarrar 

 

 

This thesis was defended successfully on 4/10/2018 and approved by: 

Defense Committee Members  Signature 

Prof. Marwan Mahmoud / Supervisor ………..……… 

Dr. Osama Al Omari / External Examiner ………..……… 

Dr. Moien Omer / Internal Examiner ………..……… 



III 
 

Dedication  

 أهدي هذا العمل اىل:

أيم احلبيبة س ندس جرار اليت من دوهنا مل أكن سأس تطيع إمتام دراس يت 

 املاجس تري حيث اكنت يه املشع وادلامع الرئييس خالل مسرييت التعلميية،

 أيب الغايل رسحان جرار، 

 العزيز داوود خاميسة، ورشيك حيايترفيق دريب 

 أبنايئ احبايئ مصطفى وأمحد،

 ة إخالص دلمعها يل يف أوقات الشدة خالل دراس يت،أخيت احلبيب

 أخوايت العزيزات شكور وزمزم،

 أيخ الغايل غيث وزوجته أس يل وابنته زينة، 

 معيت الغالية عزيزة جرار،

بسام خاميسة وخاليت فتحية وال أنىس من اذلكر معي األس تاذ الفاضل 

 خاميسة،

دلمعهن  مواحالا اىل صديقايت أسامء خليل وأسامء عفيفي وفردوس ورمي

 ،وتشجيعهن

 محمود،اىل أس تاذي الفاضل ومعلمي ادلكتور مروان 

  ،اىل روح جدي احلاج رضا جرار وجدي محمد جرار ومعيت أمل والغالية ابهتال

  ،جرار وأمحد نرص جرار اىل أرواح الشهداء األبرار أبناء معي أمحد إسامعيل

سلمني سائةل هللا عز وجل وأجعل هذا العمل وقفا هلل تعاىل عن أرواح امل

 .أن يكون يف مزيان حس ناتنا

  



IV 
 

Acknowledgment 

I would like to express my gratitude to each of my University “An-

Najah National University”, graduate studies faculty specifically clean 

energy and energy conservation-engineering program. 

I specify my thanks to my supervisor Prof. Marwan Mahmoud, who 

enriched me with valuable information about renewable energy, that 

has helped me enormously while writing my research.  

Deep thanks to all my teachers: Dr. Amer Hamouz, Dr. Abdel Raheem 

Abu Safa, Dr. Emad Breik, Dr. Muhammad Asayyed and Dr. Waleed 

al-Kukhun whom I benefited a lot from their lectures.  

Special thanks to Dr. Ikhlas Jarrar for her advices throughout the 

writing process of my research.  

I’m also grateful to my manager at work Eng. Abdullah Nierat, Mr. 

Tala Abu Rub, Eng. Jamal Muslamani and Eng. Farhan Alswadeh for 

their support during my master study time. 

I also thank my wonderful mates at the department of planning Eng. 

Asma Khalil and Eng. Reema Daraghmeh for their valuable efforts in 

helping me collecting my data.  

Special thanks also to Dr. Osama Al Omari my external examiner and 

Dr. Moien Omer the internal examiner.  

Finally, many thanks to the Czech Development Agency for their 

support of renewable energy projects in TDECO mainly 350kWp PV 

power station that made it possible for me to perform this research 

project. 

 

  



V 
 

 اإلقرار

 مقدمة الرسالة التي تحمل العنوان: أنا الموقعة أدناه

PV-GRID CONNECTED POWER SYSTEM TO TUBAS 

ELECTRIC NETWORK (TDECO): FIELD TESTS, 

EVALUATION AND OPTIMIZATION. 

 
ه اقر بأن ما اشتملت عليه هذه الرسالة إنما هي نتاج جهدي الخاص، باستثناء ما تمت اإلشارة إلي
ث حيثما ورد، وان هذه الرسالة ككل، أو أي جزء منها لم يقدم من قبل لنيل أية درجة علمية أو بح

 علمي أو بحثي لدى أية مؤسسة تعليمية أو بحثية أخرى.
 

Declaration 

The work provided in this thesis unless otherwise referenced, is the 

researcher’s own work, and has not been submitted elsewhere for any other 

degree or qualification.  

 :Student’s Name  اسم الطالب:

 :Signature  التوقيع: 

 :Date  التاريخ: 

  



VI 
 

Table of Content 

No. Contents Pages 

 Dedication III 

 Acknowledgment IV 

 Declaration V 

 Table of Content VI 

 List of Tables XI 

 List of Figures XV 

 List of Appendices XX 

 List of Abbreviations and Symbols XXII 

 Abstract XXV 

 Chapter One: Introduction 1 

1 Introduction 1 

1.1. TDECO’s Electric Grid History 1 

1.2. Objectives of the Study 12 

1.3. Thesis Structure 13 

 Chapter Two: Literature Survey 16 

2 Literature Survey 16 

 
Chapter Three: Solar and Wind Energy Potential in 

Tubas 
31 

3 Solar and Wind Energy Potential in Tubas 31 

3.1. Solar Radiation 31 



VII 
 

No. Contents Pages 

3.2. Wind Speed 37 

3.3. Temperature 41 

 
Chapter Four: The Construction of the 350 kWp PV 

Power Station 
47 

4 The Construction of the 350 kWp PV Power Station 47 

4.1. Administrative Phases in the Installation Process 47 

4.2. Geometrical Description 50 

4.3. Electrical Description 52 

 
Chapter Five:  Detailed Description of the 350 kWp 

PV Power Station Components and Evaluation 
54 

5 
Detailed Description of the 350 kWp PV Power Station 

Components and Evaluation 
54 

5.1. Site Selection Criteria 55 

5.2. PV Modules 56 

5.3. Inverters 60 

5.3.1. Inverter Efficiency 63 

5.3.2. Inverter Selection 64 

5.4. PV and Inverter Design Evaluation 65 

5.5. Electrical Protection System 70 

5.5.1. 
Protection System Configuration (Existing and 

Suggested) 
71 

5.5.2. 
Comparison Between ABB and Locally Electrical Panel 

Enclosure. 
75 

5.5.3. Sizing DC and AC Electrical Protection Devices. 79 

5.6. Grounding System 95 



VIII 
 

No. Contents Pages 

5.7. Lightning Protection System 98 

5.8. Mounting Structure 100 

5.9. Monitoring System 107 

5.10. Weather Station 107 

5.11. Cables 109 

5.11.1. DC Cables 110 

5.11.2. AC Cables 122 

5.12. Metering System 131 

5.13. Transformer 136 

5.14. Safety, Labeling and Identification 137 

5.15. Power Factor Correction 139 

5.16. On Site Tests 150 

5.16.1. Before Operation Tests 150 

5.16.2. After Operation Tests 161 

 Chapter Six: System Performance 168 

6 System Performance 168 

6.1. System Efficiency and Losses 168 

6.1.1. Uncontrollable Losses 170 

6.1.2. PV Station Equipment Efficiency and Losses 173 

6.1.3. 
Monthly and Annual Efficiency and Losses of PV 

System Equipment Summery 
178 



IX 
 

No. Contents Pages 

6.2. System Operational Performance 182 

6.2.1. Performance Ratio 182 

6.2.2. Specific Annual Yield (YS) 185 

6.2.3. Capacity Factor (CF) 186 

6.3. Actual and Proposed Energy Production 186 

6.4. Irradiance Impact on Inverter Efficiency 189 

6.5. Inverter Loading Impact on Inverter Efficiency 191 

6.6. Temperature Effect 193 

6.6.1. Temperature Effect on PV Power Station Efficiency 193 

6.6.2. 
Temperature Effect on Power Production of PV Power 

Station 
195 

6.6.3. 
Temperature Effect on DC Voltage Input of PV Power 

Station 
199 

6.7. Effect of Dirt on PV Power Station Performance. 202 

6.8. 
Number of inverter’s Maximum Power Point Tracker 

Impact on Power Production 
207 

 Chapter Seven: Economic Analysis and Optimization 210 

7 Economic Analysis and Optimization 210 

7.1. Project Cash Flow 210 

7.1.1. Project Cash Flow without Any Donations 211 

7.1.2. Project Cash Flow with Donations 218 

7.2. Financial Analysis for Replacing Transformer 223 

7.3. Cables Optimization 226 



X 
 

No. Contents Pages 

7.4. Financial Analysis for Installing Capacitor Bank 227 

7.5. Impact of Changing Meter Accuracy Class 229 

7.6. Financial Impact of Cleaning PV Power Station 230 

 
Chapter Eight: Environmental Impacts and the 

Proposed Mitigation Measures 
232 

8 
Environmental Impacts and the Proposed Mitigation 

Measures 
232 

8.1. Environmental Impacts 234 

8.2. Socio-Economic Impacts 235 

8.3. Land Use 235 

8.4. Visual Impact 235 

8.5. Accidental Releases and Occupational Health 236 

8.6. Air Pollution 236 

8.7. Waste Management 238 

8.8. Human Health 238 

8.9. Fire Risk 239 

8.10. Positive Impacts 239 

8.11. Negative Impacts 240 

 Chapter Nine: Conclusion and Recommendations 241 

9 Conclusion and Recommendations 241 

9.1. Conclusion 241 

9.2. Recommendations and Future Works 246 

 References 250 

 Appendices 253 

 ب المخلص 

 

  



XI 
 

List of Tables 

No. Table Pages 

Table (1.1) 
Grid Connected PV Stations within TDECO 

Grid (Installed and Proposed) 
7 

Table (2.1) 
Comparison between Larger and Smaller 

Gaps between Rows 
22 

Table (2.2) Ingress Protection 26 

Table (3.1) 
Maximum Solar Radiation of Typical Clear 

Day for Each Month 
33 

Table (3.2) 
Sun Rise, Sun Set and Day Time for a Typical 

Clear Sky Day 
35 

Table (3.3) 

Average Monthly Solar Energy on Horizontal 

and Tilted Surface at 22° for Tubas and 

Correction Coefficient 

36 

Table (3.4) 
Average and Maximum Wind Speed for 

Tubas in 2016 
38 

Table (3.5) 

Wind Speed Categories During the Year 

According to Roam Wind Turbine 

Specifications 

40 

Table (3.6) Ambient Temperature in Tubas 42 

Table (3.7) Cell Temperature on 2016 43 

Table (3.8) 
Daily Ambient, Actual and Calculated Cell 

Temperature on a Typical Summer Day 
45 

Table (5.1) 
Electrical Characteristics of Hanwha PV 

Module at STC 
56 

Table (5.2) 
PV Module Electrical Characteristics at 

Normal Operating Cell Temperature (NOCT) 
57 

Table (5.3) 
20kW and 27.6kW ABB Inverter 

Specifications 
60 

Table (5.4) 
Installation Comparison Between ABB and 

Locally Enclosures. 
76 



XII 
 

No. Table Pages 

Table (5.5) 
The Types and The Rated Voltages for AC 

and DC Surge Arresters. 
94 

Table (5.6) Bolts' Size and Torque 107 

Table (5.7) DC Cable Specifications 110 

Table (5.8) AC Cables Specifications 123 

Table (5.9) AC Cable Current Capacity Size 125 

Table (5.10)  Inverter’s AC Cable Replacement Cost 128 

Table (5.11) Meter Specifications 131 

Table (5.12) Current Transformer Specifications 133 

Table (5.13) Fixed Capacitor Bank Calculations on 24h 145 

Table (5.14) 

Daily PV Power Production Curve vs. Main 

TDECO Connection Point in Dec with 

Daytime Fixed Capacitor Bank 

148 

Table (5.15)  Visual Inspection 151 

Table (5.16) Grounding on Site Tests 153 

Table (5.17)  Continuity on Site Test 154 

Table (5.18) DC Cables Insulation Test 156 

Table (5.19) AC Cables Insulation Test 157 

Table (5.20) Open Circuit Voltage on Site Test 159 



XIII 
 

No. Table Pages 

Table (5.21) Polarity Test 161 

Table (5.22) Functional Test 163 

Table (5.23) Operating Voltage 164 

Table (5.24) Operational DC Strings Current 165 

Table (6.1) 
Energy Production of the 350kWp PV Power 

Station in 2016 
169 

Table (6.2) 
The Inverter Faults and the Cleaning Period 

Schedule 
171 

Table (6.3) The Inverters Faults Losses in 2016 172 

Table (6.4) Uncontrollable Losses Summery 173 

Table (6.5) Equipment Summery Losses and Efficiency 179 

Table (6.6) 
Total PV Station Equipment Efficiency with 

and without Inverters Faults 
181 

Table (6.7) 
PV Power Station Efficiency at the Daily 

Maximum Power Production 
182 

Table (6.8) Performance Ratio 184 

Table (6.9) Actual and Proposed Energy Generated 189 

Table (6.10) Irradiance Impact on Inverter Efficiency 190 

Table (6.11) 
Impact of Inverter Sizing on Inverter 

Efficiency 
192 

Table (6.12) Temperature Impact 194 



XIV 
 

No. Table Pages 

Table (6.13) 
Daily Power Production for Inverter4 on 

Feb.4th.2016 
197 

Table (6.14) 
Daily Power Production for Inverter4 on 

Aug.3rd.2016 
199 

Table (6.15) 
Temperature Effect on DC Input Voltage in 

Aug.3rd.2016. 
201 

Table (6.16) 
Effect of Dirt on PV Power Station 

Performance 
206 

Table (6.17) 

Comparison of MPPT Number Impact of 

Production Between May. 2016 and May. 

2017 

209 

Table (7.1) 
Present Value of Expected Energy Generated 

($) 
213 

Table (7.2) 
Net Cash Flow of PV power Station without 

Donations 
217 

Table (7.3) 
Net Cash Flow of PV power Station with 

Donations 
222 

Table (7.4) Financial Analysis for Replacing Transformer 225 

Table (7.5) Cable Optimization 227 

Table (7.6) Monthly PV Power Station Penalties 228 

Table (7.7) Percentage Error for Both  Metering system 229 

Table (7.8) 
Financial Impact of Cleaning PV Power 

Station 
231 

Table (8.1) 
Environmental and Safety Component’s 

Impact 
234 

  



XV 
 

List of Figures 

No. Figure Pages 

Figure (1.1)  
TDECO Daily Load Curves For Four Seasons In 

2017 
4 

Figure (1.2)  Annual Increment Of TDECO Load Demand 5 

Figure (1.3) 470kwp TDECOs’ PV Power Station 9 

Figure (1.4) 
Ortho-Photo Of 470kwp TDECOs' PV Power 

Station 
9 

Figure (1.5) 
Installed And Energy Production Share Of PV 

Power Station In TDECO 
11 

Figure (1.6) 
Program Of PV Station Energy Sharing From 

Overall PV Stations In TDECO 
11 

Figure (2.1) Defining Angles In Solar Technology 16 

Figure (2.2) Grounding Configurations 25 

Figure (3.1) Solar Irradiance Of The World 31 

Figure (3.2) 
Photovoltaic Power Potential In West Bank And 

Gaza 
32 

Figure (3.3) Hourly Daily Solar Irradiance 2016 34 

Figure (3.4) 
Average Monthly Solar Energy On Horizontal 

And Tilted Surface For Tubas 
37 

Figure (3.5) 
Average Wind Speed At 4m Height In Tubas 

During 2016 
38 

Figure (3.6) Wind Rose 39 

Figure (3.7) Wind Duration Curve 40 



XVI 
 

No. Figure Pages 

Figure (3.8) 
The Percentage Of Wind Speeds Categories 

During The Year 
41 

Figure (3.9) Temperature On Tubas At 2016 43 

Figure (3.10) Cell Temperature On 2016 44 

Figure (3.11) Actual And Calculated Cell Temperature 46 

Figure (4.1) Administrative Process Flow Chart 48 

Figure (4.2) Top View Of The 350kwp PV Power Station 50 

Figure (4.3) 
General Block Diagram For TDECO 350 kWp 

PV Station 
52 

Figure (5.1) 
The Location Of PV Power Station Before And 

After Land Preparation 
56 

Figure (5.2) 
(A) Sealed And (B) Non-Sealed PV Module 

Junction Box 
59 

Figure (5.3) ABB Inverter 62 

Figure (5.4) 
ABB Inverter Efficiency Curve According To 

Manufacturer 
63 

Figure (5.5) Inverter's Stand Layout 65 

Figure (5.6) 
Single Line Diagram For TDECO 350kwp PV 

Power Station 
66 

Figure (5.7) Existing And Suggested Enclosures Distribution 71 

Figure (5.8) ABB Enclosure And Electrical Wiring 73 

Figure (5.9) Locally Enclosures Electrical Wiring 74 



XVII 
 

No. Figure Pages 

Figure (5.10) PV Array Construction 80 

Figure (5.11) OCPDs Needed In PV Array 81 

Figure (5.12) 
Inverters Without Simple Isolation: a Type B 

RCD Protection Device Is Required 
86 

Figure (5.13) MDB In This PV Power Station 87 

Figure (5.14) 
Electrical Wiring For Air Forced Ventilation 

System 
89 

Figure (5.15) SLD For Existing And Suggested MDB 90 

Figure (5.16) G59 Decoupling Relay Connection 92 

Figure (5.17) Improper Grounding PV Module 97 

Figure (5.18) 
Lightning Protection System In 350kwp PV 

Power Station 
99 

Figure (5.19) Slab On Grade Details 101 

Figure (5.20) 
Frame Details And Trusses Before PV Modules 

Fixing 
102 

Figure (5.21) Inter Row Spacing 103 

Figure (5.22) Fence Shadow Location 106 

Figure (5.23) 
Effect Of Metals Dissimilarity Of Bolts And 

Insulating Washers 
106 

Figure (5.24) ABB Weather Station 108 

Figure (5.25) Tightened And Too Much Tightened DC Cables 118 



XVIII 
 

No. Figure Pages 

Figure (5.26) 
PV Module Wiring In Order Protection Against 

Lightning And Overvoltage On The DC Side 
119 

Figure (5.27) Multiple Circuit In The Same Manhole 121 

Figure (5.28) Closed And Non-Closed Conduits 129 

Figure (5.29) Metering Installation – Current Situation 134 

Figure (5.30) Metering Installation – Right Situation 135 

Figure (5.31) 
MV Grid For PV Power Stations And Czech 

Transformer Center 
137 

Figure (5.32) Phasor Diagram For Correcting Power Factor 140 

Figure (5.33) 
Daily PV Power Production Curve Vs. Main 

TDECO Connection Point On Dec 
143 

Figure (5.34) 

Daily PV Power Production Curve Vs. Main 

TDECO Connection Point On Dec With 24 H 

Fixed Capacitor Bank 

146 

Figure (5.35) 

Daily PV Power Production Curve Vs. Main 

TDECO Connection Point On Dec With Daytime 

Fixed Capacitor Bank 

149 

Figure (5.36) 
Thermal Image For Hot Spot In PV Module In 

This PV Power Station 
167 

Figure (6.1) 
AC Output Energy Generated Form PV Power 

Station (Kwh) In 2016 
169 

Figure (6.2) 
Illustration Figure Locates And Defines Energy 

Shortcuts 
174 

Figure (6.3) 
Total PV Station Equipment Efficiency And 

Energy Flow Summery Figure 
179 

Figure (6.4) 
Monthly Performance Ratio In 2016 With And 

Without Inverters Faults 
185 

Figure (6.5) Expected And Actual Energy Generated 188 



XIX 
 

No. Figure Pages 

Figure (6.6) 
Irradiance Impact On Inverter Efficiency On 

Juy.1.2016 
191 

Figure (6.7) 
Impact Of Inverter Sizing On Inverter Efficiency 

On Feb.2.2016 
193 

Figure (6.8) Temperature Impact On The Efficiency 195 

Figure (6.9) 
Temperature Effect On Daily Power Production 

Of Inverter 4 
196 

Figure (6.10) 
Daily Power Production For Inverter4 On 

Feb.4th.2016 
196 

Figure (6.11) 
Daily Power Production For Inverter4 On 

Aug.3rd.2016 
198 

Figure (6.12) 
Ambient Temperature Effect On DC Input 

Voltage On Aug.3.2016 
202 

Figure (6.13) Low Dirt PV Module 203 

Figure (6.14) Medium Dirt PV Module 204 

Figure (6.15) High Dirt PV Module 205 

Figure (6.16) 
Maximum Power Point Tracker Impact On Power 

Production On May.2017 
208 

Figure (7.1) 
Cash Flow Of The PV Power Station Without 

Donations 
211 

Figure (7.2) 
Net Cash Flow For The PV Power Station 

Without Donations 
210 

Figure (7.3) 
Actual Cash Flow Of The PV Power Station With 

Donations 
218 

Figure (7.4) 
Net Cash Flow For The PV Power Station With 

Donations 
221 

Figure (7.5) MV Grid For The Site 223 

  



XX 
 

List of Appendices 

No. Appendix Pages 

  Appendices 253 

  Appendix A : Cables and Conduits Calculations  253 

a DC Cable Calculations 253 

b AC Cable Calculations 263 

c NEC Tables  263 

  Appendix B : Data Sheets 265 

1 PV Module Data Sheet 265 

2 Inverter Data Sheet  266 

3 AC Cable Data Sheet 268 

4 DC Cable Data Sheet 269 

5 Weather Station Data Sheet  271 

6 Transformer Data Sheet 273 

  Appendix C: Certifications  274 

1 PV Module Palestine Standards Institution Certification  274 

2 Inverter PSI Certification 275 

  
Appendix D: Effect of Dirt, Dust and Soiling on PV Power 

Station Performance  
277 

1 Before Cleaning Low Dirt PV Module  277 

2 After Cleaning Low Dirt PV Module. 277 

3 Before Cleaning Medium Dirt PV Module 278 

4 After Cleaning Medium Dirt PV Module  278 

5 Before Cleaning High Dirt PV Module 279 

6 After Cleaning High Dirt PV Module 279 

  Appendix E: Schematics Diagrams and Tables  280 

1 TDECO Load Curve in 2017 280 

2 Daily Solar Irradiance in 2016 280 

3 Top View of the 350KWp PV Power Station-A3 281 

4 General Block Diagram 282 

5 
Temperature Effect of Daily Power Production of Inverter 

4  
282 

6 The Daily Measurements of Actual Power Production  283 

7 350KWp SLD  286 



XXI 
 

No. Appendix Pages 

8 
Comparison of Supply Voltage Requirements According to 

EN 50160 and the EMC Standards EN 61000  
287 

9 SLD for MDB 288 

  Appendix F: Checklists  290 

1 Site Selection Checklist 290 

2 PV Module Checklist 292 

3 Inverter Checklist 295 

4 PV and Inverter Design Evaluation Checklist 297 

5 Electrical Panels Evaluation Checklist 298 

6 Grounding System Checklist 301 

7 Lightning Protection System Checklist 305 

8 Mounting Structure Checklist 306 

9 Monitoring System Check List 309 

10 Weather Station Checklist 310 

11 DC Cables Checklist 311 

12 AC Cables Checklist 314 

13 Metering System Checklist 317 

14 Transformer Check List 321 

15 Safety Labeling and Identification Checklist 323 
  



XXII 
 

List of Abbreviations and Symbols 

AC Alternative Current  

AFD Agency France Development. 

AM Air Mass 

AS Australian Standards  

Avg. Average 

CB  Circuit Breaker 

CF Capacity Factor 

CT Current Transformer   

DB Distribution Board 

DC Direct Current 

DESCOs Distribution Electricity Companies 

Eexp,inv.fault 
Expected Output Energy, if There is No Inverters 

Faults  

EIA  Environmental Impact Assessment 

EPV,AC 

The Annual, Monthly or Daily Actual AC 

Output Energy Generated form PV Power 

Station (kWh). 

EQA Environment Quality Authority  

Esolar,T  Total Tilted Energy on Array Plane (kWh). 

ESP  Environmental Strategy Plan  

FFNOCT Fill Factor According NOCT 

FFSCT Fill Factor According STC  

GHG Green House Gas 

GNP Gross National Product 

GT  Total tilted irradiance on POA (kWh/m2). 

hv Temperature Coefficients of Voltage (% / °C). 

IEC International Electro Technical Commission 

IECo Israel Electricity Company 

IEEE Institute of Electrical and Electronics Engineers 

IET Institution of Engineering and Technology 

Impp Current at Maximum Power  

IR Infra-Red 

Isc Short Circuit Current PV module/ String 

LCC Life Cycle Cost  

LCOE Levelized Cost of Energy 

LV Low Voltage  

Max Maximum 

MC4 formerly Multi-Contact for the 4mm Diameter 



XXIII 
 

MCB Miniature Circuit Breaker 

MDB Main Distribution Board 

Min Minimum 

MPPT Maximum Power Point 

MRR Minimum Rate of Return  

MV Medium Voltage 

MΩ Mega-Ohm 

NEC National Electrical Code 

NERSA National Energy Regulator of South Africa  

NFPA  National Fire Protection Association  

NOCT Normal Operating Cell Temperature 

Nseries Number of Modules in Series per String 

Nstrings Number of String per MPPT 

OCPD Over Current Protection Device  

ONAN Oil Nature Air Nature 

PCB Printed Circuit Board 

Pdcr 
Rated DC Inverter Input Power From Inverter 

Datasheet 

PEA Palestinian Energy Authority  

PEC 
Palestinian Energy and Environment Research 

Center   

PENRA 
Palestinian Energy and Natural Resources 

Authority 

PERC Palestinian Electricity Regulatory Council. 

PETL  Palestinian Electricity Transmission Ltd 

PLO Palestinian Liberation Organization  

Pmax  Maximum Power  

PNA Palestinian National Authority 

POA Plane of Array 

POC Point Of Coupling 

PPA Power Purchase Agreement  

PPV@STC  
Installed Capacity of PV Power Station at STC 

(kWp) 

PR Performance Ratio 

PS Palestinian Standards 

PSI Palestinian Solar Initiative  

PV Photo Voltaic  

R.O.C.O.F Rate of Change of Frequency   

RCD Residual Current Device 

RPP Renewable Power Plants 

SPBP Simple Pay Back Period 



XXIV 
 

SPD Surge Protection Device 

STC 

Standard Testing Conditions (Irradiance of 

1000W/m² at AM 1.5 Solar Spectrum and a 

Temperature of 25°C). 

Tc Cell Temperature (°C). 

TDECO Tubas District Electricity Co. 

Tm Module Temperature (°C). 

TR Transformer. 

UL Underwriters Laboratories 

UV Ultraviolet.  

V Volt. 

Vmax,abs 
The Absolute Maximum DC Input Voltage of 

the Inverter. 

Vmpp Voltage at Maximum Power.  

Voc Open Circuit Voltage.  

VOC, string@T 
Open Circuit Voltage for String at Specific 

Temperature 

VOC,STC 
Open Circuit Voltage of Module at STC 

Condition. 

 

  



XXV 
 

PV-GRID CONNECTED POWER SYSTEM TO TUBAS ELECTRIC 

NETWORK (TDECO): FIELD TESTS, EVALUATION AND 

OPTIMIZATION 

By 

 Ishraq Serhan Jarrar 

Supervisor 

 Prof. Dr. Marwan Mahmoud 

Abstract 

Grid connected PV systems became the best alternatives in renewable energy 

fields. A 4771 kWp PV stations are connected with Tubas District Electricity 

Co (TDECO). Among these, 350kWp PV power station - donated from 

Czech Republic - is the largest solar power plant in Tubas. The site receives 

high average annual solar radiation amounting to 5.13 and 5.925 kWh/m2-

day for horizontal and tilted surfaces respectively. The annual average 

temperature of this site is about 20.5°C during 2016. 

This thesis presents the technical installation evaluation of the 350kWp PV 

power station according to national and international standards and the 

associated recommendations are presented. The system performance is 

evaluated also, two types of power losses are discussed; uncontrollable 

losses (like inverters faults and grid shortage) and PV power station 

equipment (like PV modules, DC cables, Inverters, AC cables and meter). 

The overall system efficiency is calculated, it amounts to 11.94%.The system 

operational performance parameters as annual, monthly, actual and expected 

performance ratio (PR)are calculated. The actual and expected PR is 75.6% 

and 80.2% respectively. The actual and expected specific annual yield (Ys) 

is 1640 kWh/kWp and 1740 kWh/kWp respectively. The actual and expected 



XXVI 
 

capacity factor (CF) is 18.7%, 19.81%, respectively, which is in the 

acceptable range (12%-24%).The annual actual and expected energy 

production in 2016 is 574039kWh and 609029kWh/year respectively. 

The other main aspect of this thesis is studying the effect of irradiance, 

temperature, dust and the number of maximum power point string trackers 

on the energy production of this PV power station. Moreover, studying of 

utilized DC cables and transformer optimization are discussed.  

Analysis is carried out to provide economic evaluation in terms of life cycle 

cost and energy cost. The obtained results show that the donated PV power 

station is economically feasible with an average energy cost of 

0.0276NIS/kWh while it is not feasible if TDECO was the financing body of 

the PV power station since it would not be feasible; because of high costs of 

ground and land preparation. 

Furthermore, this PV power station contributes in protecting the Palestinian 

environment since it reduces the CO2 emission by 577.97ton per year. 

 



1 
 

Chapter 1 

Introduction 

1. Introduction 

1.1. TDECO’s Electric Grid History 

Palestine is among the highest countries in the world depending on foreign 

energy sources. In 2012, about 95% of the country’s energy needs came from 

Israeli electric company, Jordan and Egypt. This almost reliance on foreign 

source consumes a significant amount of Palestine finance before few years; 

some of villages and towns were depending on diesel generators in 

production of electricity. According to the Oslo agreement between the 

Palestinian Liberation Organization (PLO) and Israel, Palestine has to 

purchase electrical energy from the Israel Electricity Company (IECo) at 

prices equal to those given to Israeli cities and sometimes higher even the 

financial income in Israel is much higher than in Palestine.   

The supplied electrical energy to Palestine is not enough to cover the load 

demands. Each city or electrical distribution company has to wait years to 

obtain extra energy. Building of electric power generation stations is not 

absolutely possible and economically feasible due to various factors. These 

factors are mainly represented in that no fuel sources are  locally available  

and Palestine is obliged to buy all needed  fuel derivatives at relatively  high 

prices only from Israel (buying oil from neighboring countries is not 

allowed). In addition, Israel controls all Palestinian imports, which means 



2 
 

that buying all necessary hardware components of such power stations 

require difficult official permission, which either is refused or requires 

waiting time for years.  

In Palestine 7 GWh of electrical energy were consumed in the year 2012. As 

a result, 6643000 kg of CO2 have been emitted. In the next 20 years, an 

increase in electricity demand by at least 50% is expected because of the 

economic boom and population growth. 

Palestinian Energy Authority (PEA) is committed to the promotion of 

renewable energies and already presented a master plan for the energy sector 

in the year 2012. Until 2020, the share of renewables in electricity generation 

shall grow to 15 percent, mainly solar energy systems are intended to 

contribute beside wind energy and biogas energy. 

Solar power technology is really clean technology because no fossil 

resources are consumed. Furthermore; Palestine is located in what is called 

solar belt and has a good solar radiation level with an a daily average of about 

7.5 hours sunshine duration and a solar radiation average ranging between 

4.8 and 6.4 kWh/m2 per day. The annual daily average of solar irradiance on 

horizontal surface is about 5.4 kWh/m2 [1], which makes producing 

electricity from sunlight feasible and economic. 

Building such solar energy projects will help Palestine economy in achieving 

partial energy independence. 

This project will help to minimize Green House Gas (GHG) emissions and 

help in keeping safe environment. 

Tubas District Electricity Company (TDECO) is one of the distribution 

companies in Palestine that has electricity concession in Tubas governorate 

and southern of Jenin governorate. It has been working since 2002 in 

supplying electrical energy for 34 communities (around 30,000 consumers). 



3 
 

Tubas is located in the northeastern part of Palestine, 100 km north of 

Jerusalem, 21 kilometers northeast of Nablus, a few kilometers west of the 

Jordan River. Tubas Governorate lies on 407km2 area, 400 meters above sea 

level at 32.323789° latitude and 35.36109° longitude with 85000-person 

population and 295.1 person/km2 population density. 

At present, many customers are asking to apply for joining TDECO, but 

unfortunately, there is no enough energy to fulfill their demands. On the 

other hand the cost of generation was very high due to the initial cost of the 

generator and its running costs, which amounts in average to 2NIS/kWh. The 

unit price of selling to consumers in these communities was 2.5 NIS/kWh, 

which is relatively very high. The unit price purchased from Israeli company 

at that time was 0.34 NIS/kWh but the electric energy supply was mostly 

limited to only 12-18 hours/day. 

TEDCO purchase electrical energy from the one IECo connection point on 

medium voltage grid 33kV and distributes it to 14 communities and to other 

20 communities (municipal and local councils) around on the low voltage 

network. The maximum available supplying power is 20 MVA while there 

is an additional demand for at least 5-8 MVA. This additional power amount 

was requested from IECo in 2012 without providing it until now.Figure 

(1.1)1 shows the daily load curve for TDECO for the four seasons; winter, 

spring, summer and autumn that represented by the following dates in 2017 

respectively (Jan.1st, March.1st, Jun.1st and Oct.1st). The maximum demand 

in winter and autumn were at afternoon around 20MVA and the minimum 

                                                 
1 See Appendix E1 for higher resolution figure 



4 
 

was in spring around 7.56MVA. In summer, the electrical consumption was 

almost the same during the 24 hours because the agricultural crops need more 

water; so the water pumping loads were increased in that time of the year, 

but in spring the load demand was from 8:00am to 4:00 pm.  

 

Figure (1.1): TDECO Daily Load Curves for Four Seasons in 2017 

Figure (1.2) shows the annual incremental of TDECO loads during the last 

four years that represent 9.58% annually. 



5 
 

 

Figure (1.2): Annual Increment of TDECO Load Demand 

Therefore, generating electricity by using photovoltaic technology is the 

only partial solution for the energy crises. 

The Palestinian Energy and Natural Resources Authority (PENRA) 

published many legislations for renewable energy in Palestine are classified 

as follows: 

A. Palestinian Solar Initiative (PSI) Program. 

This initiative has been published since 2012 according to declaration of 

cabinet 16/127/13 that allows the first 1000 domestic consumers in the west 

bank install Photovoltaic (PV) power stations on their rooftops up to 5kWp 

and sell the generated electricity to Distribution Electricity Companies 

(DESCOs) with the following incentive tariff: 

 First incentive tariff for the first 100 residential rooftop PV stations in the 

west bank is 1.07 NIS in 2012. 

0%

2%

4%

6%

8%

10%

12%

14%

16%

2014 2015 2016 2017

Annual Increment of TDECO Load Demand



6 
 

 Second incentive tariff for the second 300 residential rooftop PV stations 

in the west bank is 0.8 NIS in 2013. 

 Third incentive tariff for the rest residential rooftop PV stations in the 

west bank is 0.54 NIS in 2015. 

B. Net Metering Program 

This program has been published since 2015 according to declaration 

17/77/04 that allows any electrical DESCO’s subscriber to install PV power 

stations that generates up to 100% of its own electrical consumption, and the 

75% of extra generated power it will be transferred to the next month (this 

transfer is allowed for only one year).  

C. Power Purchase Agreement (PPA) 

This program has been published since 2015 that named (“Direct Power 

Purchase Award of Renewable Energy Generation Station” according to 

declaration of Palestinian cabinet [2]). This allows the investors to build PV 

power stations as electrical generation investment and connect it with 

Palestinian Electricity Transmission Ltd (PETL) grid with tariff of 10% less 

than the electricity tariff that generated from traditional generation according to 

renewable energy and energy conservation law Annex1 of statement 5 and 11. 

In view of the above PENRA strategy, beside to the electrical shortage, 

TDECO seeks to consume as large as possible from PV systems in covering 

the energy demands by the end of 2020, there will be 24019 kWp PV stations 

connected to TDECO grid; 20480 kWp of them will be connected to Medium 



7 
 

Voltage (MV) grid and 3539 kWp will be connected to Low Voltage (LV) 

grid.  

Table (1.1): Grid Connected PV Stations within TDECO Grid (Installed 

and Proposed) 

Year PSI (kWp) Net Metering  

(kWp) 

PPA(kWp) Total 

2013 385 15 120 520 

2014 555 127 120 802 

2015 555 127 470 1152 

2016 640 127 470 1237 

2017 800 286 2348 3435 

2018 880 420 3470 4771 

2019 880 10658 8470 20009 

2020 880 12668 10470 24019 

Table (1.1) shows the grid connected PV stations connected with TDECO 

grid classified as follows: 

1. Feed in Tariff  initiative  which has started in  2012 ,as part of Palestinian 

solar Initiative (PSI) which was  divided in three tariffs : 

A. Fist tariff was 1.07 NIS/kWh where 48 of our residential customers 

subscribed in it at 5kWp for each one (48% of the subscriber in the 

west bank). 

B. Second tariff was 0.8NIS/kWh where 64 of our residential customers 

subscribed in it at 5KWp for each one.  (21.3% of the subscriber in the 

west bank). 



8 
 

C. Third tariff was 0.54NIS/kWh where 65 of our residential customers 

subscribed in it at 5KWp for each one.  (9% of the subscriber in the 

west bank).  

2. Net metering program, 420.35kWp PV stations  connected to TDECO 

grid now that cover owners’ electrical energy consumption like (17 

agricultural  projects ,20 schools,8 public buildings, many water pumps, 

Arab American University (AAUJ), cow farm, … etc. ), some of these 

projects were donated by Czech Republic, ministry of finance, Agency 

France Development (AFD)...etc. and others financed by their owner 

account. The first net metering PV stations were installed in 2013 through 

first stage of Czech donation or on grid PV station or agricultural 

purposes and some privet projects that were before issuing the net 

metering program from PEA. 

3. PPA program, 3000kWp private sector PV station follow PTEL that were 

connected to TDECO grid and there are 2 other licenses (7000kWp) that 

will be connected in the next two years. 

4. TDECO’s PV station1, 470kWp PV power station that is donated from 

Czech Republic as shown in Figure (1.3) 

                                                 
1 Included in PPA PV power station 



9 
 

 

Figure (1.3): 470kWp TDECOs’ PV Power Station 

The geographical coordination is 32.30257° latitude 35.39138° longitude 

and the altitude is 400m above sea level in Tubas-Anon – near transformer 

maintenance center as shown in Figure (1.4). 

 

Figure (1.4): Ortho-photo of 470kWp TDECOs' PV Power Station 

First Stage 

120kWp 

Second Stage 

350kWp 



10 
 

It is divided in two following stages: 

1 First stage operated in Jun2013, under the auspices of prime Minister Dr. 

Salam Fayad and supported by the Czech Government represented by the 

Czech Development Agency .Its capacity is about 120kWp installed on 

3000m2 area .This cost of this station is $286000 (2.38$/Wp), the 

estimated production is 208800 kWh/year. 

2 Second stage was operated in Feb2015, under the auspices of Prime 

Minister Dr. Rami Al-Hamdallah and supported by the Czech 

Government represented by the Czech Development Agency. Its capacity 

is 350kWp installed on 6000m2 area western of the first stage as shown 

in Figure (1.4) the cost of this stage is 685000$ (1.96$/Wp) and the 

estimated production is 609000kWh/year. 

This thesis discusses and evaluates this stage of the PV power station.  

TDECO continues to install and encourage new PV power stations as shown 

in Figure (1.5) and Figure (1.6). 



11 
 

 

Figure (1.5): Installed and Energy Production Share of PV Power Station in TDECO 

 

 

Figure (1.6): Program of PV Station Energy Sharing from Overall PV Stations in 

TDECO 

520 802 1,152 1,237 3,435 

4,771 

20,009 
24,019 

1.0% 1.5% 1.9% 1.7% 2.7% 7.0% 26.9%

29.5%

 -

 5,000

 10,000

 15,000

 20,000

 25,000

 30,000

2013 2014 2015 2016 2017 2018 2019 2020

0%

5%

10%

15%

20%

25%

30%

35%

k
W

p
Energy Production Share of Installed and Proposed PV 

Power Station in TDECO

Total Installed PV Stations (kWp)

PV Energy Production Share (%)

0%

10%

20%

30%

40%

50%

60%

70%

80%

Program of  Installed and Proposed PV Station Energy 

Sharing from Overall PV Stations in TDECO 

PSI Net Metering PPA



12 
 

1.2. Objectives of the Study 

The main goal of this thesis is the technical, financial and environmental 

evaluation of the 350kWp PV power station. Thesis objectives can be 

pointed as the followings: 

 Measuring and analysis the environmental parameters like solar 

irradiance on horizontal and tilted surfaces, wind speed and ambient and 

cell temperature in the location of PV power station in 2016. 

 Describing and technically evaluate PV power station equipment 

according to national and international codes. 

 Investigating the possibility of modifying the system performance and 

safety. 

 Finding out the actual and expected efficiency and losses for this PV 

power station. 

  Finding out system performance figures like performance ratio, 

specific yield, capacity factor and  

 Investigating the impact of irradiance, inverter loading on inverter 

efficiency. 

 Investigating the temperature effect, dirt and the number of inverters’ 

MPPT on PV power station production. 

  Determination the economic feasibility of installing this PV power 

station with different financing methods. 

 Investigating of optimizing DC cables and transformer. 



13 
 

 Studying the financial impact of using power factor correction, high 

meter accuracy and cleaning the PV power station. 

 Studying the environmental positive and negative impacts and 

mitigation measures in this PV system. 

1.3. Thesis Structure 

This thesis is divided to nine chapters, the followings illustrate those briefly: 

Chapter One: TDECOs’ Electric Grid History 

This chapter as an introduction talks about electricity history in TDECO, the 

general situation of producing electricity from solar energy in Palestine and 

the current situation of renewable energy in TDECO. 

Chapter Two: Literature Survey 

Chapter Three: Solar and Energy Potential in Tubas 

This chapter discuss the weather data in Tubas; solar irradiance, wind and 

temperature by using local weather station, installed within the second PV 

power station donated from Czech Republic on 2015. 

Chapter Four: The Construction of the 350 kWp PV Power 

Station   

In this chapter, the 350 kWp PV power station administrative phases in the 

installation process, general geometrical and electrical construction 

description are discussed. 



14 
 

Chapter Five: Detailed Description of the 350 kWp PV Power 

Station Components and Evaluation  

This chapter discuss the site selection criteria, technical evaluation for all 

components this PV power station that according to national and 

international codes. The checklist for each component are prepared to 

facilitate system installation evaluation. 

Chapter Six: System Performance 

This chapter discusses system efficiency and losses, system operational 

parameters, the energy production actual and expected, irradiance, 

temperature, dust, number of maximum power point impacts on PV power 

station. 

Chapter Seven: Economic Analysis and Optimization 

The aim of this chapter is to predict the income of this PV power station 

during its lifetime, which is considered as 20 years. The feasibility study of 

replacing transformers to reduce the running cost of this PV power station. 

Studying the cables selection to optimize the cost, studying the feasibility of  

installing new capacitor bank to this PV power station, commercial 

comparison between using class 0.5 and class 1 meters and finally studying 

the economic impact of cleaning this PV power station from the dust are 

considered in the study. 



15 
 

Chapter Eight: Environmental Impacts and the Proposed 

Mitigation Measures 

This chapter presents the environmental positive and negative impacts and 

mitigation measures in this PV system. 

Chapter Nine: Conclusion and Recommendations 

This chapter represent the main conclusion and recommendations in this 

thesis. 

  



16 
 

Chapter 2 

 Literature Survey 

2. Literature Survey 

Exact knowledge of the sun's path is important for calculating irradiance 

values and the yields of solar energy systems. The sun's altitude can be 

described at any location by the solar altitude and the solar azimuth. 

When talking about solar energy systems, due south is generally given as 

(a = 0°). 

Angles to the east are indicated with a negative sign (east: a = -90°). To 

the west, angles are given without a sign (or with a positive sign) (west: 

A = 90°) [3]. 

 

 

Figure (2.1): Defining Angles in Solar Technology 

 



17 
 

Literature Survey of the PV Power Station Classification 

The PV power station classification that according to National Energy 

Regulator of South Africa (NERSA) [4] “Compliance with this grid 

connection code shall be applicable to the Renewable Power Plants (RPP) 

depending on its rated power and, where indicated, the nominal voltage at 

the point of coupling (POC). Accordingly, RPPs are grouped into the 

following three categories: 

(a) Category A: 0 – 1 MVA  

This category includes RPPs with rated power of less than 1 MVA and 

connected to the LV voltage (typically called 'small or micro turbines'). This 

category shall further be divided into 3 sub-categories:  

(i) Category A1: 0 - 13.8 kVA  

This sub-category includes RPPs of Category A with rated power in the 

range of 0 to 13.8 kVA.  

(ii) Category A2: 13.8 kVA – 100 kVA  

This sub-category includes RPPs of Category A with rated power in the 

range greater than 13.8 kVA but less than 100 kVA.  

(iii) Category A3: 100 kVA – 1 MVA  

This sub-category includes RPPs of Category A with rated power in the 

range 100 kVA but less than 1 MVA.  

Note: For RPPs connected to multi-phase supplies (two- or three-phase 

connection at the POC), the difference in installed capacity between phases 

may not exceed 4.6 kVA per phase.  

(b) Category B: 1 MVA – 20 MVA  



18 
 

This category includes RPPs with rated power in the range equal or greater 

than 1 MVA but less 20 MVA.  

(c) Category C: 20 MVA or higher  

This category includes RPPs with rated power equal to or greater than 20 

MVA”. 

Literature Survey of Inverter 

According to [5], Inverters work by converting DC voltage and current into 

AC voltage and current to be used to meet electricity demand for various 

appliances. The most common types of Inverters are: 

a) Stand-alone Inverters are used in isolated or decentralized systems not 

connected to the utility grid, where the Inverter receives its DC current and 

voltage from batteries that are charged by PV system. 

b) Grid connected inverters regulates the amount of voltage and the current 

that is received from DC and then converts it into an alternating current by 

ensuring that the power will be in phase or synchronized with the grid-power. 

This will allow the exportation of any excess power generated by the PV 

system to the utility grid. 

Grid connected inverters; in addition to its basic functionality of DC to AC, 

conversion should perform the following functions: 

a) Synchronize its output voltage and frequency with the AC mains. 



19 
 

b) Disconnect from the grid if the voltage and frequency deviate from the 

allowable limits or there is a loss of gird. 

c) Ensure the output AC waveform is within the specified harmonic and 

flicker limits 

d) Adjust the PV array operating voltage to ensure maximum power is 

extracted from the PV Array. 

e) Monitor earth and isolation faults on the DC side of the solar PV system. 

Inverters typically come in two classifications that will have an impact on 

the design process of the Solar PV System. These are: 

a) Isolated inverters with at least simple separation between the AC and DC 

sides. 

b) Non-isolated inverter without at least simple separation between the AC 

and DC sides, also known as transformer-less inverter. 

According to [6], when considering the most appropriate inverter size, the 

following oversizing/ under sizing considerations should be considered. 

Why Undersize the Inverter? 

a. PV modules in UK operate for much of the time below the nominal 

rated power. Nominal rated power is the output of the module under 

STC reached relatively infrequently in the UK. Consequently, inverters 

will spend much of their time operating at power levels below the 

nominal array rating. 



20 
 

b. Inverter efficiency is generally lower when operating at low power 

levels. With a degree of inverter under sizing, it is possible to take the 

normal operating regime higher up the efficiency curve and hence 

decrease inverter losses at times of normal irradiance levels. 

c. The array is located in a sub- optimal location, orientation or pitch and 

such as is expected to produce a lower than normal output. 

d. When grid connection limit is imposed on a site it may be beneficial to 

considerably undersize the inverter to gain maximum generation. An 

example would be a domestic inverter of 3.68 kW with a 6 kW array 

connected so as to produce more power when in sub-optimal conditions 

Manufacturers will provide guidance on the maximum under sizing 

possible. 

e. While a larger inverter may provide a system with a higher output 

power, the increased annual yield may not be justified by the extra cost 

(i.e. the system has a lower IRR). 

Why Oversize the Inverter?  

a. Limited inverter selection  

b. A system with an inverter smaller than the array will, on occasions of 

high irradiance, have the output clipped- the inverter will simply not 

be able to deliver all the available power to the grid. Oversizing the 

inverter prevents this happening. 

c. May increase inverter life. 

d. The array is expected to produce significant power – for example, an 

array on a solar tracker or located in a very sunny location. 



21 
 

Literature Survey of Photovoltaic Modules 

Solar PV Modules typically come in three safety classes as per IEC 61730 

according to [5] : 

a) Class A modules meet the safety class II, these are mandatory. 

b) Class B modules meet the safety class 0, these are not permitted. 

c) Class C modules meet the safety class III, these are not permitted. 

Consideration should be given to Modules installed in coastal environments, 

in such locations compliance with IEC. 

Potential Induced Degradation (PID), according to the Institution of 

Engineering and Technology [6], to reduce the power output of a cell. It 

occurs when the voltage between the cell and the ground drives ions from 

the module glass (and other parts of PV laminate) into the semiconductor 

and reduce its effectiveness. The presses is amplified by increased humidity, 

temperature and system voltage. 

Certain types of PV modules are more prone to PID and the manufacturers 

may specify particular grounding arrangement for PV system. Some PID 

effects can be reversed, and the full output of a module restored, by 

connecting one of the DC current currying conductors to earth (connecting 

DC negative to earth for the P-type module). This is termed ‘functional 

grounding’. 



22 
 

IEC are currently working on a standard for module manufacturers to test for 

the impact of PID on a particular module (IEC 62804 (Draft)) system voltage 

durability qualification test for crystalline silicone modules. 

Literature Survey of Spacing between Modules’ Rows 

The spacing between module rows according to the Institution of 

Engineering and Technology [6], is dictated by the site topography and the 

degree of inter row shading that is deemed acceptable. Providing sufficient 

access between rows for cleaning or grass cutting vehicles also needs to be 

considered. Table (2.1) shows that the advantages and disadvantages either 

larger gap or smaller gap between rows. 

Table (2.1): Comparison between Larger and Smaller Gaps between 

Rows 

smaller gap between 

rows 

Larger gap between 

rows 

 

more inter row 

shading  

Less inter row shading  Shading  

worse KWh/KWp  Better KWh/KWp  KWh/KWp 

performance 

larger array (KWp) 

can be installed 

Smaller array (KWp) 

can be installed 

Installed 

capacity(KWp) 

In general, foundation options for ground-mounted PV systems include the 

following that according to International Finance Cooperation [7]: 

• Concrete piers cast in-situ: These are most suited to small systems and 

have high tolerance to uneven and sloping terrain. They do not have large 

economies of scale. 



23 
 

• Pre-cast concrete ballasts: This is a common choice for manufacturers 

with large economies of scale. It is suitable even at places where the 

ground is difficult to penetrate due to rocky outcrops or subsurface 

obstacles. This option has low tolerance to uneven or sloping terrain, but 

requires no specialist skills for installation. Consideration must be given 

to the risk of soil movement or erosion. 

• Driven piles: If a geotechnical survey proves suitable, a structural steel 

profile driven into the ground can result in low-cost, large-scale 

installations that can be quickly implemented. Specialist skills and pile 

driving machinery are required, but may not always be available. 

• Earth screws: Helical earth screws typically made of steel have good 

economics for large-scale installations and are tolerant to uneven or 

sloping terrain. These require specialist skills and machinery to install. 

• Bolted steel baseplates: In situations where the solar plant is located over 

suitable existing concrete ground slabs, such as disused airfield runway 

strips, a steel baseplate solution bolted directly to the existing ground 

slabs.  

Literature Survey of Grounding System  

The international standard IEC60364 explain the five basic methods of 

grounding and providing the neutral of an electrical installation where it is 

required. The five methods are abbreviated TN-C, TN-S, TN-C-S, TT and IT. 

The first letter denotes the source of power from a star-connected winding.  

T denotes that the star point of the source is solidly connected to earth, which 

is usually at a location very near to the winding. 



24 
 

I denotes that the star point and the winding are isolated from earth. The star 

point is usually connected to an inductive impedance or resistance. 

Capacitive impedance is never used. 

The second letter denotes the consumer. The consuming equipment needs  

to be earthed. There are two basic methods that can be used to earth the body 

of electrical equipment. These methods are denoted by the letters T and N. 

The letter N is sub-divided into other letters, S and C, thus giving N-S, N-C 

and N-C-S. 

T denotes that the consumer is solidly earthed independently of the source 

grounding method. 

N denotes that a low impedance conductor is taken from the earth connection 

at the source and routed directly to the consumer for the specific purpose of 

grounding the consuming equipment. 

S denotes that the neutral conductor (N) routed from the source is separate 

from the protective earthing (PE) conductor, which is also routed from the 

source. This implies that five conductors need to be routed for a three-phase 

consumer. 

C denotes that the neutral conductor and the protective earthing conductor 

are one and the same conductor. This means that four conductors need to be 

routed for a three-phase consumer. 

TN-C-S denotes that combined PEN conductors from transformer to 

consumer distribution point, but separate PE and N conductors in fixed 

indoor wiring and flexible power cords 

The different earthing (grounding) types are illustrated in Figure (2.2): 



25 
 

 

Figure (2.2): Grounding Configurations 

Literature Survey of Protection System  

Combiner boxes have protective and isolation equipment, such as string fuses 

and disconnects (also known as load break switches), and must be rated for 

outdoor placement using, for example, ingress protection (IP). An explanation 

of the IP bands is provided in Table (2.2) depending on the solar PV plant 

architecture and size, multiple levels of junction boxes can be used [7]. 

 

 

 

 



26 
 

Table (2.2): Ingress Protection 

First 

Digit  

Protection from Solid 

Objects 

Second 

Digit 

Protection from 

Moisture 

0 Non-protected 0 Non-protected 

1 

Protection against solid 

objects greater than 50mm 1 

Protected against 

dripping water 

2 

Protection against solid 

objects greater than 12mm 2 

Protected against 

dripping water when 

tilted 

3 

Protection against solid 

objects greater than 2.5mm 3 

Protected against 

spraying water 

4 

Protection against solid 

objects greater than 1.0mm 4 

Protected against 

splashing water 

5 Dust protected 5 

Protected against water 

jets 

6 Dust tight 6 

Protected against heavy 

seas 

    7 

Protected against 

immersion 

    8 

Protected against 

submersion 

According to [8], installing Type B earth leakage protection units ensures the 

safety of individuals and correct functioning for alternating current (AC), 

direct current (DC) or mixed current (AC/DC) intensities up to frequencies 

of 1 kHz. Type A and AC earth leakage protection units do not detect smooth 

residual direct currents. Moreover, Type A units become more sensitive 

when a pulsating earth leakage current is accompanied by a smooth direct 

current. In these cases, protection is not as effective and compromises the 

expected safety levels. 

All protection elements installed upstream must have the same or higher 

rating than those installed downstream, never lower, in order to guarantee 



27 
 

the correct operation of the selective classification process. Therefore, if 

Type B is the maximum protection level of an element, a Type A or AC unit 

cannot be installed downstream. 

Where an electrical installation includes a PV power supply system without 

at least simple separation between the AC side and the DC side, an RCD 

installed to provide fault protection by automatic disconnection supply shall 

be type B according to IEC 62423. 

According to [9], Where the PV converter is, by construction, not able to 

feed DC fault currents into the electrical installation, RCD of type B 

according to IEC62423 is not requires. 

RCDs are classified into different categories, as follows, in according with 

their ability to ensure protection against various types of earth fault currents: 

1.Type AC 

• for residual sinusoidal alternating currents 

2.Type A 

• as for type AC; and 

• for residual pulsating direct currents 

3.Type B & F (MS IEC-62423) 

• as for type A; and 

• for smooth DC 

Selection of RCDs according to the type of protection RCDs can be used 

where it is necessary to protect a circuit or an installation against dangerous 



28 
 

residual currents. The three main areas for such protection are as follows 

according to [10] : 

1.Protection against fire. 

Tracking currents are linked to ageing of installations where a reduction in 

humidity and drying out of pollution at the surface of isolating materials may 

lead to a degradation of the isolating material and the deposit of carbon. This 

may cause fire. Recommended to use RCDs having IΔn not higher than 300 

mA at the beginning of installations. In domestic applications, where 

installations are not maintained, the use of such RCDs is highly 

ecommended. For fire protection, the RCD must break all phase(s) and 

neutral. It may be an S Type RCD in order to allow discrimination with other 

RCDs downstream. 

2.Fault protection (protection against indirect contact) 

Fault between a live part and earth 

 May cause exposed metal parts to reach a dangerous voltage. 

 A person touching such live parts may be exposed to a potentially fatal 

 Shock risk, so the fault must be eliminated. 

 This is referred to as protection against indirect contact. 

 Choice of RCD must follow recommendations made in MS IEC 

60364. 



29 
 

In general, a medium sensitivity RCD can be selected for this type of fault 

protection. 

e.g. An RCD with a rated residual operating current of up to 300 mA. If this 

value is appropriate it is possible to use a single RCD for fire protection and 

fault protection (protection against indirect contact) 

3.Basic protection (protection against direct contact) 

 Direct contact between a person and a live conductor, a residual current 

will flow through the body of the person. 

 This current may cause a fatality if not eliminated quickly. 

 An RCD having /Δn not higher than 30 mA will provide adequate 

protection in this situation (additional protection against electric shock). 

In a domestic application, a 30 mA RCD used at the origin of the installation 

can provide efficient protection covering fire protection, fault protection and 

basic protection. For basic protection the RCD should not be a delayed type 

(selective type). 

Literature Survey of Power Factor Correction in PV Systems 

Solar PV Plants Generation starts when sun shining is active generation 

period. Solar Inverter Designed to produce power at unity power factor 

meaning they only produce active power;  so the reactive power needed 

from loads will be consumed from utility grid In effect this reduces the power 

factor, as the grid is then supplying less active power, but the same amount 

of reactive power. Therefore total power factor during the month will be 



30 
 

decreased, could be cause some penalties from IECo to solve this problem 

we should install Capacitor Bank in solar Plant Substation.  

Project developers should maintain a power factor close to unity; there are 

other states that charge for the reactive power consumed by the PV plant. 

Although most modern central inverters can be made to operate at leading 

power factor, supplying the reactive power during hours of high irradiance, 

there may be a need to include a capacitor bank to compensate reactive power 

during periods of low irradiance. It is advisable to select inverters that can 

compensate the reactive power [7]. 

Main benefits of correct Pf is  

 Avoid Penalty 

 Increased Efficiency in the System Capacity. 

 Reduces Voltage Drop 

 Reduces System Losses. 

 

  



31 
 

Chapter 3 

 Solar and Wind Energy Potential in Tubas 

3. Solar and Wind Energy Potential in Tubas 

This chapter discusses the weather data in Tubas; solar irradiance, wind and 

temperature by using local weather1 station, installed within the second PV 

power station donated from Czech Republic on 2015. 

3.1. Solar Radiation 

Palestine is located within the global solar belt countries, which have high 

solar energy potential Figure (3.1) [11] 

 

Figure (3.1): Solar Irradiance of the World 

                                                 
1 The detailed specifications of this weather station is presented in section 5.10 



32 
 

The photovoltaic power potential in west bank is shown in Figure (3.2) [12]. 

Tubas is located in the northern part of Palestine distinguished with very 

good solar irradiance amounting to about 5.4 kWh/m2-day [1] .  

 

Figure (3.2): Photovoltaic Power Potential in West Bank and Gaza 

This section discusses the irradiance data from TDECOs’ weather station, 

which has 22° titled and horizontal irradiance sensor. From the data have 

been collected in 2016, the total yearly irradiance was 2171 kWh/m2 and 

1866 kWh/m2 on tilted plane and horizontal plane respectively.  

Tubas  



33 
 

Table (3.1) shows the measurements of the maximum solar radiation of 

typical clear day for each month on tilted surface Gt(max) and horizontal 

surface Gh(max), at solar noon time that were measured on 15 minutes interval 

basis.  

Table (3.1): Maximum Solar Radiation of Typical Clear Day for Each 

Month 

Date Gt(max) W/m2 Gh(max) W/m2 Solar Noon 

Time for Tilted 

Jan.6.2016 806 574 11:30 AM 

Feb.4.2016 902 678 11:30 AM 

Mar.1.2016 1011 790 11:45 AM 

Apr.1.2016 1070 908 12:30 PM 

May.11.2016 1026 945 12:45 PM 

Jun.1.2016 1008 950 12:30 PM 

Jul.1.2016 1002 950 12:30 PM 

Aug.3.2016 987 907 12:30 PM 

Sep.1.2016 965 843 12:45 PM 

Oct.2.2016 958 772 11:15 AM 

Nov.3.2016 838 608 11:15 AM 

Dec.9.2016 833 562 11:30 AM 
 

From the previous table and Figure (3.3) 1 the solar noon in Tubas is between 

11:30am and 12:45pm around the year. The maximum solar irradiance for 

horizontal surface was 950 W/m2 on Jun and July, the maximum solar 

irradiance for tilted surface was 1070W/m2 on April, the lowest solar 

irradiance for horizontal surface was 562 W/m2 on Dec and the lowest one 

for tilted surface was 806W/m2 on Jan. 

                                                 
1 See Appendix E1 for high resolution figure  



34 
 

Usually the irradiance of horizontal surface is greater than tilted surface 

during noon time in Jun, July, August and September because the altitude 

angle of the sun is higher, this is dispute these readings because uncalibrated 

equipment.  

 

Figure (3.3): Hourly Daily Solar Irradiance 2016 

In 20161, the sun was shining for 4576 hours and 45 minutes, which 

represents 52% of the year. Table (3.2) shows the sunrise, sunset and the sun 

shine time for a typical clear sky day of each month. The average daytime 

was 12 hours and 30 minutes; the maximum daytime was 14 hours and 30 

                                                 
1 2016 was leap year 

0

200

400

600

800

1000

1200

W
/m

2

Hourly Daily Solar Irradiance 2016

Tilted Irradiance Horizontal Irradiance



35 
 

minutes in Jun and July while the minimum daytime was 10 hours and 15 

minutes in Jan.  

Table (3.2): Sun Rise, Sun Set and Day Time for a Typical Clear Sky 

Day 

  Sun Rise 

time (ts) 

Sun Set 

time (tss) 

Day Time 

(td) 

Day Time for 

each month 

Jan.6 6:30 AM 5:00 PM 10:30 325:30:00 

Feb.4 6:15 AM 5:15 PM 11:00 319:00:00 

Mar.1 5:45 AM 5:45 PM 12:00 372:00:00 

Apr.1 6:15 AM 7:00 PM 12:45 382:30:00 

May.11 5:30 AM 7:30 PM 14:00 434:00:00 

Jun.1 5:15 AM 7:45 PM 14:30 435:00:00 

Jul.1 5:15 AM 7:45 PM 14:30 449:30:00 

Aug.3 5:30 AM 7:45 PM 14:15 441:45:00 

Sep.1 6:00 AM 7:00 PM 13:00 390:00:00 

Oct.2 5:15 AM 5:30 PM 12:15 379:45:00 

Nov.3 5:45 AM 4:45 PM 11:00 330:00:00 

Dec.9 6:15 AM 4:30 PM 10:15 317:45:00 

Min     10:15 317:45:00 

Max     14:30 449:30:00 

Avg     12:30 381:23:45 
 

Table (3.3) shows the average monthly solar irradiance for each tilted and 

horizontal surface and the monthly tilt correction coefficient calculated 

according to Equation 3.1. 

K =  
Gt(avg)

Gh(avg)
 

(3.1) 

Where, 

K: Tilt correction coefficient. 



36 
 

Gt(avg): Average monthly solar irradiance per day for tilted surface (kWh/m2-

day).  

Gh(avg): Average monthly solar irradiance per day for horizontal surface 

(kWh/m2-day).  

Table (3.3): Average Monthly Solar Energy on Horizontal and Tilted 

Surface at 22° for Tubas and Correction Coefficient 

 Gt(avg) kWh/m2-

day 

Gh(avg) kWh/m2-

day 

Tilt Correction 

Coefficient (K) 

Jan 3.70 2.70 1.372 

Feb 4.38 3.32 1.320 

Mar 5.52 4.39 1.256 

Apr 6.38 5.55 1.151 

May 7.09 6.60 1.076 

Jun 7.58 7.39 1.027 

Jul 7.51 7.41 1.013 

Aug 7.22 6.89 1.047 

Sep 6.68 5.95 1.122 

Oct 6.20 5.03 1.233 

Nov 5.11 3.74 1.365 

Dec 3.72 2.59 1.434 

The average solar irradiance during 2016 was 5.13 kWh/m2-day and 5.925 

kWh/m2-day for horizontal and tilted surface respectively. Despite Gt(max)  

has the maximum value on April as discussed previously on Table (3.1).  



37 
 

 

Figure (3.4): Average Monthly Solar Energy on Horizontal and Tilted Surface for Tubas 

3.2. Wind Speed 

The anemometer1 has been installed at the height of 4m from the ground, 

which measures the wind speed and direction. The measuring data is not 

suitable to study the wind energy potential necessary to perform a feasibility 

study. This needs an installation height, which is not less than 12 meter. 

Table (3.4) shows the average and maximum wind speed for the year 2016. 

The average wind speed during the year was 2.21m/s and the maximum wind 

speed was 15m/s. 

 

 

 

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

1 2 3 4 5 6 7 8 9 10 11 12

k
W

h
/m

2
-d

ay

Average Monthly Solar Energy on Horizantal and Tilted 

Surface for Tubas

Gt(avg) kWh/m2-day Gh(avg) kWh/m2-day



38 
 

Table (3.4): Average and Maximum Wind Speed for Tubas in 2016 

  Average Wind Speed 

(m/s) 

Maximum  Wind Speed 

(m/s) 

Jan 1.98 15 

Feb 1.87 8 

Mar 2.41 13 

Apr 2.06 11 

May 2.58 13 

Jun 2.25 9 

Jul 2.52 9 

Aug 2.37 9 

Sep 2.15 9 

Oct 1.98 9 

Nov 2.42 12 

Dec 1.90 12 

 

Figure (3.5): Average Wind Speed at 4m height in Tubas during 2016 

The representation of the statistical repartition of the wind directions of this 

site is shown on the Figure (3.6) “wind rose diagram” that shows wind 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

Average Wind Speed (m/s)



39 
 

direction frequency and its direction in degrees. We notice that the wind 

comes mainly from the west and to a lower extent from the south in this 

particular site. 

 

 

 

Figure (3.6): Wind Rose 

The hourly data was taken to draw the wind duration curve shown in Figure 

(3.7), the repetition was for the wind speed is less than 4m/s and the 

maximum repetition was 10% for 2m/s. 



40 
 

 

Figure (3.7): Wind Duration Curve 

The data were fitted to small wind turbine 3.5kW from roam energy with the 

specifications shown in Table (3.5). 

Table (3.5): Wind Speed Categories During the Year According to 

Roam Wind Turbine Specifications. 

Status Speed Ranges of 

Roam Wind Turbine 

Hours 

Repetition on 

This Site 

Frequency  

During the 

Year 

off less than 2.8m/s 7359 84.06% 

Cut-in wind speed from2.8m/s to 11m/s 1179 13.47% 

Rated wind speed from11m/s to 22m/s 89 1.02% 

Cut-out wind 

speed 

more than 22m/s 127 1.45% 

 

Figure (3.8) shows this turbine will operate during 14.49% (more the 2.8m/s 

and less than 22 m/s) from the year. Therefore, this site with this installation 

height not suitable for installing wind turbine with cut in wind speed 2.8m/s. 

0%
1%
2%
3%
4%
5%
6%
7%
8%
9%

10%
11%
12%

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

F
re

q
u

an
cy

Wind Speed (m/s)

Wind Duration Curve



41 
 

If there is another wind turbine with cut in wind speed less than 2m/s, it could 

be more suitable. 

 

Figure (3.8): The Percentage of Wind Speeds Categories During the Year 

3.3. Temperature 

The ambient temperature is an important factor affects the PV output power. 

This section discusses the obtained data for specified site; ambient 

temperature, cell temperature and make a comparison between the real and 

calculated cell temperature. All measured data is based on 5-minute interval 

taken from temperature sensor1 in 2016. 

84.1%

13.5%

1.0% 1.5%

The Percentage of Wind Speeds Categories During the 

Year

less than 2.8m/s from2.8m/s to 11m/s

from11m/s to 22m/s more than 22m/s



42 
 

Table (3.6) and Figure (3.9) show that the highest ambient temperature is 

42°C in May, the lowest ambient temperature is 0.1°C in Jan and the average 

is 20.5°C. 

Table (3.6): Ambient Temperature in Tubas 

Month Temperature Max 

°C 

Temperature 

Avg.  °C 

Temperature Min 

°C 

Jan 19.6 10.4 0.1 

Feb 27.5 14.7 6.6 

Mar 28.0 16.1 8 

Apr 36.0 21.9 10.4 

May 42.0 22.4 13 

Jun 39.5 27.8 16.3 

Jul 37.2 27.3 19.8 

Aug 36.8 27.0 20.2 

Sep 36.6 25.3 17.6 

Oct 37.4 23.6 15.2 

Nov 29.9 18.0 5.9 

Dec 19.8 10.9 2.8 

 



43 
 

 

Figure (3.9): Temperature on Tubas at 2016 

Table (3.7) and Figure (3.10) show the monthly maximum, average and 

minimum cell temperature during 2016, which were 69.1°C in Jun and -

4.7°C in Jan respectively. 

Table (3.7): Cell Temperature on 2016 

Month Maximum Cell 

Temperature °C 

Monthly Average 

Cell Temperature °C 

Minimum Cell 

Temperature  °C 

Jan 46.3 12.2 -4.7 

Feb 55.1 18.1 2.0 

Mar 53.8 20.0 7.5 

Apr 63.4 27.1 6.0 

May 68.4 27.6 10.0 

Jun 69.1 33.6 12.3 

Jul 66.2 32.6 15.0 

Aug 66.7 31.0 17.5 

Sep 67.6 30.7 12.0 

Oct 67.1 28.1 11.4 

Nov 57.7 20.7 3.0 

Dec 49.6 13.3 0.0 

0.00

10.00

20.00

30.00

40.00

50.00
C

°

Tempreture on Tubas at 2016

Temperature Min °C Temperature Max °C

Temperature Avg.  °C



44 
 

 

Figure (3.10): Cell Temperature on 2016 

The approximate cell temperature can be calculated by using Equation3.2 [13]. 

TC ≈  Tamb + 0.0256 ∗ Gh (3.2) 

Where, 

Tc : Cell Temperature (°C). 

Tamb : Ambient Temperature (°C) 

Gh : Horizontal Solar Irradiance (W/m2) 

Table (3.8) shows the actual and calculated cell temperature on July.1st.2016, 

which is a typical summer day.  

-5
5

15
25
35
45
55
65
75

°
C

Cell Tempreture on 2016

Average Cell Temperature °C

Maximum Cell Temperature °C

Minimum Cell Temperature  °C



45 
 

Table (3.8): Daily Ambient, Actual and Calculated Cell Temperature on 

a Typical Summer Day 

Date/Time Horizontal 

Irradiance 

(W/m2) 

Ambient 

Temp.(C°) 

Actual 

Cell 

Temp.(C°) 

Calculated 

Cell 

Temp.(C°) 

12:00 AM 0 22 20 22 

1:00 AM 0 22 20 22 

2:00 AM 0 22 20 22 

3:00 AM 0 21 19 21 

4:00 AM 0 21 19 21 

5:00 AM 4 22 19 22 

6:00 AM 89 22 21 24 

7:00 AM 275 24 28 32 

8:00 AM 469 27 38 39 

9:00 AM 647 28 46 45 

10:00 AM 792 30 50 50 

11:00 AM 900 31 51 54 

12:00 PM 946 32 54 56 

1:00 PM 934 32 54 56 

2:00 PM 863 32 50 54 

3:00 PM 731 31 46 50 

4:00 PM 565 31 41 45 

5:00 PM 385 30 34 40 

6:00 PM 198 28 30 33 

7:00 PM 36 26 25 27 

8:00 PM 0 24 22 24 

9:00 PM 0 23 21 23 

10:00 PM 0 23 21 23 

11:00 PM 0 23 20 23 

Figure (3.11) shows that there is slight difference between the real and 

calculated cell temperatures. 



46 
 

 

Figure (3.11): Actual and Calculated Cell Temperature 

  

0

10

20

30

40

50

60

0
:0

0
1
:0

0
2
:0

0
3
:0

0
4
:0

0
5
:0

0
6
:0

0
7
:0

0
8
:0

0
9
:0

0
1
0

:0
0

1
1

:0
0

1
2

:0
0

1
3

:0
0

1
4

:0
0

1
5

:0
0

1
6

:0
0

1
7

:0
0

1
8

:0
0

1
9

:0
0

2
0

:0
0

2
1

:0
0

2
2

:0
0

2
3

:0
0

°
C

Actual and Calculated Cell Tempreture

Actual Cell Temp.(C°) Calculated Cell Temp.(C°)



47 
 

Chapter Four 

The Construction of the 350kWp PV Power Station 

4. The Construction of the 350 kWp PV Power Station   

The PV power station consists of PV modules, inverters, DC and AC 

electrical protection equipment, grounding system, lightning protection 

system, galvanized steel structure, monitoring system, weather station, MV 

transformer, DC and AC cables. 

In this chapter, the 350kWp PV power station administrative phases in the 

installation process, general geometrical and electrical construction 

description are discussed. 

4.1. Administrative Phases in the Installation Process 

This PV station classified as (“Direct Power Purchase Award of Renewable 

Energy Generation Station” according to declaration of Palestinian cabinet 

[2]) go through following administrative process. 



48 
 

 

Figure (4.1): Administrative Process Flow Chart 

Figure (4.1) shows the 6 installation stages. This station was the second 

largest PV station in the West Bank in 2013, and the Palestinian Electricity 

Transmission Ltd (PETL) was not established yet. Unfortunately, no clear 

administrative regulations published then, so some of these stages were not 

completed. The detailed description of each stage is as follows:  

1. Applying the application of new PV power station to Palestinian Energy 

and Environment Research Center (PEC) and PETL includes the 

followings: 

a. Technical study including station capacity, station technology, site 

location, land ownership and electrical grid availability. 

b. Financial study and capability, including local and international partners 

information, company registration and its official financial documents, 

feasibility studies and financial studies of the project. 

Applying the 

application 

 Application 

Evaluation 

Establishing 

Company  

Primary Temporary 

Licenses 
Final Licenses 

Installing RE 

project 



49 
 

Note: we skipped point 1.b from this PV power station because it is a grant 

from the Czech Republic Development Agency. TDECO apply the 

importance of this project and their suffering from electricity shortage 

without it. 

2. Application evaluation, that includes the followings: 

a. Technical approval from PEC (to check their strategic compatibility).  

b. Technical approval from PTEL (to check electrical grid and connection 

point compatibility). 

This PV power station was, according to PEC strategy at that time and it was 

already compatible with the electrical grid and the connection point because 

it was the first PV station on this site. 

3. Establishing the company according to  corporation Law 

This PV power station follows TDECO so it was no need to establish a new 

company. 

4. Primary temporary licenses  

It was not completed for this PV power station because the regulation was 

not published yet. 

5. Final licenses 

It was not completed for this PV power station because the regulation was 

not published yet. 

6. Installing RE project  

This PV power station was installed as mentioned in the next chapter. 



50 
 

4.2. Geometrical Description 

This station lies in approximately 6000m2 rocky area with parallelogram 

shape area that has been rounded by a fence that has one main gate in the 

northeastern corner. 

 

Figure (4.2): Top View of the 350kWp PV Power Station 

Figure (4.2) 1 shows the 1400 PV modules in this PV power station divided 

into two areas western and eastern sides denoted by ‘W’ and ‘E’ respectively, 

are separated by 3m width, 75 meter long service road for maintenance 

purposes. 

The PV modules are fixed on eight galvanized steel tables at each side that 

oriented directly to the south with 22° tilt angle. Each western table has 100 

PV modules (4 rows x 25columns) and each eastern table has 80 PV modules 

                                                 
1 See Appendix E3 for high resolution figure 



51 
 

(4 rows x 20columns) except one table in the far north of eastern area that 

has 40 PV modules (4rowsx10columns). The Inverters have been fixed on 

the structure behind the PV modules that distributed in all PV power station 

tables. 

All DC cables were either fixed in structure or inserted in suitable conduit 

that has been buried underground between tables as shown in Figure (4.2). 

All inverter AC cables lies between inverters and Main Distribution Board 

(MDB) are inserted in conduits and buried underground through service 

road. Each 7.5m the concrete manholes are inserted for cabling maintenance 

and grounding checkpoints. The first three manholes from the far south 

contains pure copper electrodes for the station grounding system.  

The main cable lies between MDB and transformer are directly buried 

underground. 

We can see also in the far north MDB which is fixed on (2.5x1.3x0.15m) 

reinforced concrete surface and a monitoring system distribution board (DB) 

is located there about two meters away from the MDB.  

The weather station is fixed above before last table in area E near monitoring 

system DB in the far north. 

The lightning protection system is fixed at 12 m galvanized steel pole; we 

can find it on the far north of area W, which has three grounding system pits 

outside, the far northern fence by 20m. 

The last component of this power system is the transformer, which is located 

outside the northern fence on the west side of the main gate. 



52 
 

4.3. Electrical Description 

This PV power station generates electricity by converting solar irradiance to 

DC electrical power through PV modules that connected to inverters, which 

converts DC power to AC. Then this power is transferred to 33kV network 

through a 33/0.4kV distribution transformer. For equipment and human 

safety purposes, there are some necessary DC and AC electrical protection 

equipment like DC fuses, surge protection device (SPD) on DC and AC side, 

residual current device (RCD), AC circuit breakers in LV side and isolator 

switch on MV side, all these components are shown in Figure (4.3) 1 

 

 

Figure (4.3): General Block Diagram for TDECO 350 kWp PV Station 

This system consists 1400 PV modules (Hanwha Solar One 250Wp) 

connected by 4 and 6 mm2 DC cables to 12 inverters (11inverters ABB 

27.6kW and 1 inverter ABB 20 kW), which fixed behind the structure. These 

inverters have built in DC/AC junction box with all necessary DC fuses, DC 

surge protection device (SPD), AC SPD and DC/AC isolator switch.  

                                                 
1 See Appendix EAppendix E4 for high resolution figure 



53 
 

Each 120 PV modules are connected to 27.6kW inverters, 20 modules in 

series and 6 strings in parallel. Regarding the 20kW inverter, 80 PV modules 

are connected to it where 20 modules in series and 4 strings in parallel. Then 

each string connected to 15A fuse inside DC/AC junction box and DC SPD 

connected in parallel of these fuses then goes to the inverter. The inverter 

output goes to DC/AC switch, while AC SPD parallel connected to this 

switch. 

4x16mm2 and 4x25mm2 AC cables are connected between the inverter 

DC/AC switch and MDB. 

The MDB contains RCDs and AC circuit breakers then goes through 

4x240mm2 underground AC cable to step up, 400kVA-0.4kV/33kV 

transformer, then to TDECO medium voltage (MV) utility grid.  

All these parameters will be discussed in detail in the next chapter. 

 

  



54 
 

Chapter Five 

 Detailed Description of the 350kWp PV Power Station 

Components and Evaluation 

5. Detailed Description of the 350 kWp PV Power Station 

Components and Evaluation  

This chapter discuss the site selection criteria, technical evaluation for all 

components of this PV power station according to national (Palestinian 

Standards(PS)) and international codes as Australian Standards (AS), the 

National Electrical Code (NEC)-USA, the German Energy Society and the 

Institution of Engineering and Technology (IET)-United Kingdom1 

considering the following aspects, : 

 Site selection criteria 

 PV modules. 

 Inverters. 

 PV and inverter design 

 Electrical protection system in AC and DC combiner boxes, comparison 

between the existing and proposed protection devices and finding the 

advantages and disadvantages in each case. 

 MDB design, ventilation and its components (like AC inverter breakers, 

RCDs, busbar, main circuit breaker and G59). 

 Grounding system. 

 Lightning protection system. 

                                                 
1 International standards are used because the absence of local standards  



55 
 

 Mounting structure. 

 Monitoring system. 

 Weather station. 

 Calculating the voltage drop and power losses for AC and DC cables 

and summarize the main parameters that should be taken into account 

when selecting cables. 

 Metering system.  

 Transformer. 

 Safety, labeling, and identification. 

 Power factor correction. 

 Before and after on site tests. 

The checklist for each component are prepared to facilitate system 

installation evaluation an Appendix F. 

The financial evaluation of system will be discussed in chapter 7 

5.1. Site Selection Criteria  

In general, the process of site selection must consider the constraints of each 

site and impact on the cost of the electricity generated. There are no clear-

cut rules for site selection; the checklist shown in Appendix F.1 lists the basic 

requirements and procedures necessary to assist developers with the site 

selection process. 

Figure (5.1) shows the land before and after preparation  

 



56 
 

 

Figure (5.1): The Location of PV Power Station Before and After Land Preparation 

5.2. PV Modules 

The system consists of 1400 PV modules, each module capacity is 250Wp, 

polycrystalline cell dimensions (156 mm × 156 mm), module 

dimensions(1636mm x 988mm x 40mm) this module contains 60(6x10) cells 

with 3 sets of diodes and protection class IP 67, its brand name is Hanwha 

Solar One which is Chinese product. 

Electrical characteristics at Standard Test Conditions (STC) of this PV 

module is illustrated in a Table (5.1). 

Table (5.1): Electrical Characteristics of Hanwha PV Module at STC 

 

Maximum Power (Pmax)  250 W 

Open Circuit Voltage (Voc) 37.7 V 

Short Circuit Current (Isc, mod@ STC) 8.79 A 

Voltage at Maximum Power 

(VMPPT) 
30.4 V  

Current at Maximum Power (IMPPT) 8.23 A  

Module Efficiency (%) 15.50% 

Before After 



57 
 

Electrical characteristics at Normal Operating Cell Temperature (NOCT) at 

(NOCT, 45±3°C) defined at irradiance of 800W/m2, ambient temperature 

20°C and wind speed 1m/s are shown in Table (5.2). 

Table (5.2): PV Module Electrical Characteristics at Normal Operating 

Cell Temperature (NOCT). 

Power Class  250 W  

Maximum Power (Pmax)  183 W 

Open Circuit Voltage (Voc) 35 V 

Short Circuit Current (Isc ,mod@ NOCT)   7.13 A 

Voltage at Maximum Power (VMPPT) 27.6 V  

Current at Maximum Power (IMPPT) 6.64 A  

Module Efficiency (%) 14.20% 

(See Appendix B.1 for full data sheet.) 

The fill factor (FF) is an important parameter to characterize the PV module 

performance. For crystalline PV modules 0.75<FF<0.85 [3]. FF is obtained 

as follows.  

FF =  
Vmpp ∗  Impp

VOC ∗  Isc,mod
 (5.1) 

The fill factor, according to STC (FFSCT) is 0.755 and according to NOCT 

(FFNOCT) is 0.7344. 

Various standards are in place to provide safety and performance tests for 

PV modules according to Palestinian local standers [14] and IEC standards 

[6], photovoltaic modules should have the following certificates: 

1 PS 2676: 2012 or IEC 61215. 



58 
 

2 PS 2684: 2012 or IEC 61730-1 

3 PS 2685: 2012 or IEC 61730-2 

This module complies Palestinian standers1 and has other certifications as 

follows: 

 Harsh Environment: Verified against Salt Mist and Ammonia 

Corrosion (IEC 61701 and IEC 62716). 

 ISO 9001 quality standards and ISO 14001 environmental standards. 

 OHSAS 18001 occupational health and safety standards. 

 Conformity to CE (low Voltage Directive and EMI), fire tested class 

E (EN 13501-1). 

Total effective area of PV modules is as mentioned in Equation 5.2 

APV,station =  NCell ∗ ACell ∗  Nmod (5.2) 

Where, 

APV, station : PV power station area (m2) 

A Cell : Module area (m2)  

N Cell: Number of cell per module 

N mod : Number of modules of PV power station 

Then, 

APV, station= 2044.224m2 

 

                                                 
1 This module compatible to the local standards see Appendix C1 for PSI certification 

 



59 
 

 

Figure (5.2): (A) Sealed and (B) Non-Sealed PV Module Junction Box 

This module has a good sealed junction box that sold by white suitable 

insulator sheet as shown in the Figure (5.2-A). On other hand, Figure (5.2-

B) shows non-sealed junction box of another type. From our practice, this 

sealing gives the following advantages: 

1. It keeps diodes and metallic strips from dust, air and wet. 

2. It protects PV module junction box for long life.  

3. It decreases the probability of corrosion. 

4. The white insulator has good properties in heat dissipation so sealed 

one will dissipate the heat faster than the non-sealed.  

5. It decreases the probability of loose connections inside the PV module 

junction box that could happen when charging, installing and 

maintenance the PV module.  

Appendix F.2 shows us the main aspects that should be considered when we 

select a PV module. 

(A) (B) 



60 
 

Therefore, this PV module comply with all requirements.  

5.3. Inverters  

A power inverter is an electronic device that converts the DC voltage and 

current to AC, which has many classifications as mentioned in chapter 2.This 

PV power station contains 12 grid-tie, transformer-less inverter; its brand is 

ABB Italian product. One of them has 20kW rated capacity named TRIO-

20.0-TL-OUTD-S2X-400 (inverter number 1), and the others rated capacity 

are27.6kW named TRIO-27.6-TL-OUTD-S2X-400 (inverters number 2-

12)1. Table (5.3) shows the main inverters specifications. The S2X inverter 

version has additional protection options that will be discussed in section 5.5. 

This inverter has two connection options; one or two MPPT input 

connections, the last one is used in this PV power station. 

Table (5.3): 20kW and 27.6kW ABB Inverter Specifications 

  20kW Inverter 27.6kW Inverter 

Absolute maximum DC 

input voltage (Vmax,abs) 
1000 V 1000 V 

Start-up DC input 

voltage (Vstart) 

430 V (adj. 

250...500 V) 

430 V (adj. 250...500 

V) 

Operating DC input 

voltage range 

(Vdcmin...Vdcmax) 

0.7 x Vstart…950 V 

(min 200 V) 

0.7 x Vstart…950 V 

(min 200 V) 

Number of independent 

MPPT 
2 2 

Rated DC input voltage 

(Vdcr) 
620 V 620 V 

Rated DC input power 

(Pdcr) 
20750 W 28600 W 

                                                 
1 This inverter compatible to the local standards see Appendix C.2 for PSI certification 



61 
 

  20kW Inverter 27.6kW Inverter 

Maximum DC input 

power for each MPPT 

(PMPPTmax) 

12000 W 16000 W 

DC input voltage range 

with parallel 

configuration of MPPT at 

Pacr 

440...800 V 500...800 V 

DC power limitation for 

each MPPT with 

independent 

configuration of MPPT at 

Pacr , max unbalance 

example 

12000 W [480 

V≤VMPPT≤800 V] 

the other channel: 

Pdcr-12000 W [350 

V≤VMPPT≤800 V] 

16000 W [500 

V≤VMPPT≤800 V] 

the other channel: 

Pdcr-16000 W 

[400 V≤VMPPT≤800 

V] 

Maximum DC input 

current (Idcmax) / for each 

MPPT (IMPPTmax) 

50.0 A / 25.0 A 64.0 A / 32.0 A 

Maximum input short 

circuit current for each 

MPPT 

30A 40A 

AC grid connection type 
Three-phase 3W+PE 

or 4W+PE 

Three-phase 3W+PE 

or 4W+PE 

Rated AC power (Pacr 

@cosφ=1 ) 
20000 W 27600 W 

Maximum AC output 

power (Pacmax @cosφ=1) 
22000W 30000W 

AC voltage range 320...480 V 320...480 V 

Maximum AC output 

current 
33A 45A 

Total current harmonic 

distortion 
< 3% < 3% 

All of these inverters are fixed outside on the galvanized steel structure under 

the photovoltaic’ structure using appropriate number of bolts as shown in 

Figure (5.3). 



62 
 

 

Figure (5.3): ABB Inverter 

In this PV power station, the inverter input voltage at STC is determined 

according to Equation 5.3 

V OC,string @T  = Nseries  ∗ VOCT,mod@T (5.3) 

Where, 

V OC, string@T: Open circuit voltage for string at specific temperature. 

Nserise: number of modules in series per string 

VOCT,mod@T: Open circuit voltage for PV module at specific temperature. 

V OC, string@STC= 37.7 V * 20 module 

V OC, string@STC= 754V. 

ABB Trio S2X 

inverter 

ABB Enclosure 



63 
 

5.3.1. Inverter Efficiency 

This section shows the theoretical inverter efficiency as mentioned in 

inverters catalogue and the actual inverter efficiency in 2016, nevertheless 

the irradiance impact on inverter efficiency and inverter-loading impact on 

inverter efficiency will be discussed in section 6.4 and section 6.5 

respectively. 

Theoretical Inverter Efficiency 

Figure (5.4) illustrates theoretical inverter efficiency as mentioned in ABB 

catalogue.  

 

Figure (5.4): ABB Inverter Efficiency Curve according to Manufacturer  

The operated voltage of the inverter at STC is 608V; so from the efficiency 

curve the closest two readings are 98% and 97% for 620V and 500V 

respectively. By using interpolation according to Equation5.4, 



64 
 

y − y1 =  
y2 − y1

x2 − x1
∗ (x − x1) (5.4) 

The theoretical inverter efficiency is 97.9%. 

Actual Inverter Efficiency 

The actual inverter efficiency is determined by dividing the actual total 

output AC energy on the total input DC energy of the inverter,   

ηinv,actual =
Einv,AC

Einv,DC
∗ 100% (5.5) 

η inv, actual: Actual inverter efficiency 

Einv, DC: Total DC energy injected in the inverters (kWh). 

Einv, AC: Total AC energy produced from inverters and injected in AC cables 

(kWh). 

In 2016 the Einv, DC was 596508kWh and the Einv,AC  was 574040 kWh. 

Therefore; the η inv, actual is 96.23%. 

5.3.2. Inverter Selection 

In Appendix F.3 shows the main item that should be considered in selecting 

and evaluating the inverter 

Figure (5.5) shows the inverters’ stand fixed behind the rail of support 

structure which has good ventilation and there is no direct sun. This stand’s 

design was checked by structural engineer.  



65 
 

 

Figure (5.5): Inverter's Stand Layout 

5.4. PV and Inverter Design Evaluation  

This section discusses and evaluates the sizing of PV modules and inverters 

in the 350kWp PV power station. The sizing and evaluation of other 

equipment will be discussed later in this chapter. 

Figure (5.6)1shows the detailed single line diagram in this 350kWp PV 

power station. There are 12 inverters in this PV power station and 1400 PV 

modules, each 120 PV modules are connected to 27.6kW inverters, 20 

modules are connected in series and 6 strings are in parallel. Each 3 strings 

are connected to one MPPT input regarding the 20kW inverter. 80 PV 

modules are connected to it where 20 modules in series and 4 strings are in 

parallel, each two strings are connected to one MPPT input. These inverters 

have a built in DC/AC junction box with all necessary DC fuses, DC surge 

protection devices (SPD), AC SPD and DC/AC isolator switch. Then it is 
                                                 
1 See   Appendix E6 for high resolution figure 



66 
 

connected to the MDB, which contains main Circuit Breaker (CB), inverters’ 

CB and Residual Current Devices (RCD) for each inverter, then it connected 

to MV transformer and then to TDECO’s grid. 

 

 

Figure (5.6): Single Line Diagram for TDECO 350kWp PV Power Station 

The following points shall be assessed for sizing and evaluating the design 

of PV modules and inverters: 

1. Maximum Inverter Input Voltage 

The maximum DC input voltage of the inverter to which the string will be 

connected should never be exceeded; because this can damage or decrease 

the inverter’s operational lifetime. 

The highest module voltage that can occur in operation is the open circuit 

voltage. The coldest cell temperature reached at the PV power station is -4°C 



67 
 

Table 3.6 The corresponding maximum DC input voltage at the inverter 

inputs for this PV power station is determined according to Equation 5.3 and 

Equation 5.6 

VOC,module@T = VOC,module@STC(1 + hv ∗ (TC − 25 °C)) (5.6) 

Where, 

VOC ,STC: Open circuit voltage of module at STC condition. 

hv: Temperature Coefficients of Voltage(% / °C). 

Tc: Cell temperature (°C). 

VOC ,module@-4°C = 37.7 V*(1+ -0.31%*(-4°C-25°C)) 

VOC ,module@-4°C =41.1V 

Then, 

VOC, string @-4°C=20 modules *41.1V 

VOC, string @-4°C = 821.8V which is less than 1000V (the absolute maximum 

DC input voltage of the inverter (Vmax,abs) ). 

2. Minimum Inverter Input Voltage 

The minimum open circuit voltage in the hottest daytime temperature must 

be greater than the inverter DC turn-off voltage. 

The highest cell temperature recorded at the PV power station is 69.1°C 

Table 3.6 The corresponding minimum DC input voltage on the inverter 

inputs in this PV power station is determined according to Equation5.3 and 

Equation 5.6  

VOC ,module@69°C = 37.7 V*(1+ -0.31%*(69°C-25°C)) 

VOC ,module@69°C = 32.56V 

Then, 



68 
 

VOC, string @69°C = 651.15V, which is more than 430 V (inverter start-up DC 

input voltage (Vstart)). 

3. Maximum Inverter Input Current 

The inverter must be able to safely withstand the maximum PV array current, 

which is obtained according to Equation5.7  

Imax,mpp =  Nstring ∗  Isc,   mod@ STC (5.7) 

Imax, MPPT: Maximum input current for MPPT (A). 

Nstring: Number of string per inverter. 

For inverters (2-12) Trio27.6 with 2 MPPT connection: 

Imax, MPPT= 3 * 8.79 A 

Imax, MPPT= 26.37A which is less than 32A 

For inverters (2-12) Trio27.6 with 1 MPPT connection (in case of this 

connection): 

Imax, MPPT= 6 * 8.79 A 

Imax, MPPT= 52.74A which is less than 60A 

For inverter (1) Trio20 with 2 MPPT connection: 

Imax, MPPT= 2 * 8.79 A 

Imax, MPPT= 17.58 A which is less than 25A 

For inverter (1)  Trio20 with 1 MPPT connection (in case of this connection): 

Imax, MPPT= 4* 8.79 A 

Imax, MPPT= 35.16A which is less than 50A 

Therefore; the maximum input current of PV arrays are less than the 

maximum allowed input current for inverter in case of 1 or 2 MPPT 

connection. 



69 
 

4. Maximum String Power for Each Inverters’ MPPT Inputs 

The inverter MPPT input rated power range must be sized with the power of 

PV array MPPT points at different temperatures. 

PMPPT,inv = PPV@STC ∗ Nstring ∗  Nserise (5.8) 

PMPPT, inv: Inverter power or each MPPT input. 

For inverters (2-12) Trio27.6  

PMPPT, inv = 250Wp * 20 modules *3 strings 

PMPPT, inv = 15kWp, which is less than 16kWp. 

For inverter (1) Trio20  

PMPPT, inv = 250Wp * 20 modules *2 strings 

PMPPT, inv = 10kWp, which is less than 12kWp. 

5. Inverter Sizing 

The optimal inverter sizing is determined according to Equation5.9 [6] 

0.8 < Power Raio < 1.1 (5.9) 

Where, 

Power Ratio =  
Pinv,DC

PPV@STC
 

Pinv,DC : Inverter DC input rated power. 

For inverters (2-12) Trio27.6  

The installed PV module capacity PPV@STC is 30kWp and the Pinv,DC is 

28.6kW therefore, the power ration is 0.953 which is in the acceptable limit  

For inverter (1) Trio20  

The installed PV module capacity PPV@STC is 20kWp and the Pinv,DC is 

20.75kW therefore, the power ration is 1.0375 which is in the acceptable 

limit before 9/11/2017. Then the Trio20 inverter has been replaced to 



70 
 

Trio27.6 inverter, the new power ratio is 1.43, therefore the new one is an 

oversized inverter. Therefore, inverter1 should be reinstalled to Trio20 

inverter. 

Appendix F.4 shows the summery of the PV and Inverter evaluation that 

passed all inspection points.  

5.5. Electrical Protection System 

Protection system in the photovoltaic system is very important that isolate 

the faulty parts from the rest. The objective of a protection scheme is keeping 

the power system stable by isolating only the faulted components, whilst 

leaving as much of the photovoltaic station as possible still in operation. This 

section discusses the followings: 

 Protection system configuration (existing and suggested). 

 Comparison between ABB and locally electrical panel enclosure. 

 DC electrical protections. 

 AC electrical protections. 

 Utility grid protection. 

Note: The local standard of electrical installation requirements for inverter 

energy systems and grid protection devices are adopted from AS4777-1, 

which does not apply the system ratings more than 10kVA for single phase 

unit or 30kVA for three phase units. Therefore this PV power station will be 

evaluated according IEC62548:2011. 



71 
 

5.5.1. Protection System Configuration (Existing and Suggested) 

In general, PV power stations should have electrical protection devices for 

both DC and AC sides. These devices would be distributed in one or 

electrical panel termed hereafter enclosures. This section discusses the 

existing and suggested enclosure distribution in this PV power station, as 

shown in Figure (5.7) that would have two configurations of enclosures 

distribution; the existing one by using ABB S2X version of inverter 

enclosure (termed hereafter; ABB enclosure) and another suggested by using 

two locally made enclosure one for DC protections and another for AC 

protections (termed hereafter; locally enclosures). While the types and sizes 

of the electrical protection devices will be discussed in section 5.5.3. 

 

Figure (5.7): Existing and Suggested Enclosures Distribution 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PV 

PV 

MDB 

Transformer 

To Grid 

DC 

Combiner 1 
Inverter 1 AC Box 1 

DC 

Combiner 

12 

Inverter 

12 

AC Box 

12 

 

Inverter 

12 

 

PV 

 

12 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PV 

PV 

MDB 

Transformer 

To Grid 

Same location 

ABB 

Enclosure 

DC Side 1 
Inverter 1 

ABB 

Enclosure 

AC Side 1 

 

ABB 

Enclosure 

DC Side 12 

 

Inverter 

12 

ABB 

Enclosure 

AC Side 12 

 

B. Suggested A. Existing 



72 
 

A. Description of ABB Enclosure (Existing Protection System 

Configuration) 

This enclosure inputs are DC cables coming from PV modules and the output 

is AC inverter cable that running to MDB. 

As shown in Figure (5.8), ABB enclosure is equipped by 2MPPT inputs, 4 

pairs (+/-string) for each MPPT input, this system design use only 3 pairs 

from each MPPT input (in other words, the 6 strings are equally distributed 

on 2MPPT input).DC input connected to two inputs (MPPT) 4 string for each 

one and 3phase plus neutral output and monitoring cable. This type of 

enclosure has each DC and AC protections. This enclosure includes the 

following components: 

a. Eight pieces of MC4 mail connector (formerly Multi-Contact for the 

4mm diameter) which is commonly used for connecting solar modules, 

double insulated, IP68 and rated 1000 V. 

b. Printed Circuit Board (PCB) 

c. Positive and negative fuses for all string. 

d. Four terminal jumpers, two for positive and two negative; for 

converting MPPT mode purpose. 

e. DC overvoltage surge arresters. 

f. AC overvoltage surge arresters. 

g. AC/DC isolator switch. 

h. Five pieces of AC terminals for output cable. 



73 
 

 

Figure (5.8): ABB Enclosure and Electrical Wiring 

B. Description of Locally Enclosures (Suggested Protection System 

Configuration). 

Two individual locally made enclosures are suggested to install them instead 

of ABB enclosure; one for DC protection devices and another for AC 

protection devices. As shown in Figure (5.9). 

DC Side AC Side 

DC SPD 

+ve Fuses 

-ve Fuses 

AC SPD 

Input DC Cables Out AC Cable



74