lighting and earthing design according to ieee80_2000 and iec 62305-2 by aya emad mahmoud ...

168 Pages·2012·7.36 MB·English

LIGHTING AND EARTHING DESIGN ACCORDING TO
IEEE80_2000 AND IEC 62305-2

BY
AYA EMAD MAHMOUD HAMID
INDEX NO. 074015

Supervisor
Dr. ABDULL ALRAHMAN ALI KARRAR

REPORT SUBMITTED TO
University of Khartoum
In partial fulfillment of the requirement for the degree of
B.Sc. (HONS) Electrical and Electronic Engineering
(CONTROL ENGINEERING)
Faculty of Engineering
Department of Electrical and Electronic Engineering
September 2012
DECLARATION OF ORIGINALITY

I declare that this thesis entitled “LIGHTING AND EARTHING
DESIGN ACCORDING TO IEC 62305-2 AND IEEE80_2000” is my
own work except as cited in the references. The report has not been
accepted for any degree and is not being submitted concurrently in
candidature for any degree or other award.

Signature : _________________________
Name : ____________________________
Date : _____________________________

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DEDICATION

To my parents, without whom this thesis would not have seen
light,
To my brother and sisters,
To my colleagues and friends,
To all who taught me a letter

To you all I dedicate this work with all my love and respect;
hoping that it will be of some benefits and use...

Aya

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ACKNOWLEDGEMENT

Without the contribution of many people this thesis would not have been
accomplished, I regret it is not possible to name these people in this
acknowledgement.
In particular I am extremely indebted to Dr. Abdull Alrahman Ali Karrar for his
sustained support and fruitful supervision.
Above and before all I thank God who gave me the will and ability to do this work
and put this humble effort between your hands

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ABSTRACT
. Lightning is one of the most beautiful displays in nature but it can have
devastating results. Lightning can kill people, destroy properties and cause millions of
dollars of damage. Thus protection against this phenomenon is crucial for avoiding
such loss.
Absolute protection against lightning is impossible but through deployment
of a judicious combination of defenses, the lightning protection engineer can attempt
to mitigate the lightning consequences. The need for protection, the economic benefits
of installing protection measures and the selection of adequate protection measures
should be determined in terms of risk management.
The IEC 62305-2 standard presents a procedure to assess the risk due to all
possible effects of lightning flashes to structures. The risk management procedure
described in IEC 62305-2 is rather complicated. It would be useful for lightning
protection engineers to have a software tool to carry out this risk assessment.
The purpose of substation grounding/earthing is to protect the equipment from
efeect of short circite and surges and lightning strikes and to protect the operating
persons in the substation. The substation earthing system is necessary for connecting
neutral points of transformers and generators to ground and also for connecting the
non current carrying metal parts such as structures, overhead shielding wires, tanks,
frames, etc. to earth. Earthing of surge is through the earthing system.
In this project we developed two software tools. One to perform the tedious
risk assessment as described in IEC 62305-2. The other is to assess the safety of the
ground grid design as described in IEEE80-2000 standard. Both of them were
developed using visual basic and they were proved to be reliable and intuitive

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صلختسملا
زيذئ.ٌاسَلاا مخمي ٌا قزبهن ٍكًي ٔ .ِزيذي ّجئاخَ ٍكن . ّؼيبطنا ٗف ذْاشًنا مًجا ٍي زبخؼي قزبنا
ِذْ مثي ٖدافخن اذج ًّٓي ِزْاظنا ذْ ذظ ّياًح غظٔ اذٓنٔ . ٍيلاًناب بسحح زئاسخ بسياًي ثاكهخًًنا
.زئاسخنا

تطسإب تًًصًنا ِذيجنا غَإًنا ٍي ّػًٕجي زشَ للاخ ٍي ٍكنٔ ّهيحخسي قزبنا ذظ ّمهطًنا ّياًحنا
بيكزح ٍي ّيداصخللاا ذئإفنأ ّياًحنا ٗنا ّجٕحنا. قزبنا راثأ ٍي ذحي ٌا ٍكًي قزبنا ٍي ّياًحنا سذُٓي
.زغاخًنا ِرادا ثيح ٍي دذحح ٌا بجي ّيفاكنا ّياًحنا زيباذح رايخخأ ّياًحنا

IEC 62305-2

ةرادإ ءازجإٔ ، ثاءاشًُنا ٗهػ قزبنا ٍي ّهًخحًنا راثلاا غيًجن زغاخًنا ىيمخن ءازجإ ضزؼي سايمي
ٗسذًُٓن ذيفًنا ٍي ٌٕكيس،ذمؼًناIEC 62305-2 سايمًنا ٗف فٕصًٕنا زغاخًنا
.زغاخًنا ِذْ ىيمخن جيازب ىٓيذن ٌٕكي ٌا كػإصنا ٍي ّياًحنا

ثازيثاح ٍي ّطحًنا ٗف ٍيهياؼنا صاخشلاأ ثاذؼًنا ّياًح ْٕ ْٕ ثاطحًنا طيرأح ٍي ضزغنا
ثلإحًنا ٍي ِذياحًنا غامُنا ػبزن اذج ٖرٔزظ ثاطحًنا طيرأح واظَٔ،فصإؼنأرٕصمنأ كػإصنا
.ضرلاا ٗنا ثأشًُنا مثي رايح مًححلا ٗخنا ّيَذؼًنا ءازجلاا ػبر اعيأ ضرلاا ٗنا ثاذنًٕنأ
.IEC 62305 سايمي ٗف حظٕي ْٕاًك زغاخًنا ىيمخن لٔلأا ٍيجياَزب ىيًصخب عٔزشًنا اذْ ٗف اًُل ذلٔ
Visual تفن واذخخسا ىح ذلٔ .IEEE80-2000 ٗف حظٕي ْٕاًك ضرلأن ٗكبشنا ىيًصخناتيلاس ىيمخن يَاثنأ
.آًياذخخسا ّنٕٓس غي ٍيجياَزبنا داًخػا ٍكًي َّا جبثا ذلٔ . ٍيجياَزبنا ىيًصخن Basic

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TABLE OF CONTENTS
DECLARATION OF ORIGINALITY .................................................................................... I
DEDICATION …………………………………………………………………………………………...…II
ACKNOWLEDGEMENT ...................................................................................................... IV
ABSTRACT ............................................................................................................................. V
صلختسملا ............................................................................................................................... VI
LIST OF FIGURES ................................................................................................................ XI
LIST OF TABLES ................................................................................................................ XII
LIST OF ABBREVIATIONS ............................................................................................. XIII
CHAPTER ONE ...................................................................................................................... 1
1.1. Overview .............................................................................................................................. 1
1.2. Problem statement............................................................................................................... 3
1.3. Motivation ........................................................................................................................... 3
1.4. Objectives ............................................................................................................................ 4
1.5. Thesis Layout ........................................................................................................................ 4
2. .......................................................................................................... CHAPTER TWO
.................................................................................................................................................. 5
2.1. Introduction ......................................................................................................................... 5
2.2. History of lightning ............................................................................................................... 6
2.3. Lightning Damage ................................................................................................................. 8
2.3.2 Human injury .............................................................................................................................. 8
2.3.3 Physical Damage .................................................................................................................... 9

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2.4. Loss ...................................................................................................................................... 9
2.5. Risk ....................................................................................................................................... 9
2.5.1. Tolerable Risk ...................................................................................................................... 10
2.5.2. Risk components ................................................................................................................. 10
2.5.2.1. Risk components for a structure due to flashes to the structure .............................. 10
2.5.2.2. Risk component for a structure due to flashes near the structure ........................... 11
2.5.2.3. Risk components for a structure due to flashes to a service connected to the
structure 11
2.5.2.4. Risk component for a structure due to flashes near a service connected to the
structure 12
2.5.3. Composition of risk components related to a structure ..................................................... 12
2.5.3.1. Composition of risk components with reference to the source of ............................ 13
damage ......................................................................................................................................... 13
2.5.3.2. Composition of risk components with reference to the type of damage .................. 13
2.5.4. Assessment of risk components for a structure .................................................................. 14
2.6. OBJECTIVE OF EARTHING .................................................................................................... 15
2.7. REQUIREMENT OF GOOD EARTHING .................................................................................. 16
2.8. Earthing conductor ............................................................................................................. 16
2.9. Earth Resistance ................................................................................................................. 16
2.10. Earth grid ............................................................................................................................ 16
2.11. Step Potential and Touch Potential .................................................................................... 17
2.11.1. Step Potential ................................................................................................................. 17
2.11.2. Touch Potential............................................................................................................... 17
2.12. Permissible Current through a Human Body during the Fault ............................................. 18
2.13. Common Shock Situations .................................................................................................. 18
2.14. Protective Surface Material ................................................................................................ 19
2.15. Design Procedures of a Grounding System ......................................................................... 19
2.16. Design Modifications .......................................................................................................... 21
2.17. Tolerable Body Current Limits ............................................................................................ 21
2.18. Circuit Equivalents for Common Shock Situations .............................................................. 23
2.18.1. Resistance of the Human Body ....................................................................................... 23
2.18.2. Touch and Step Voltage .................................................................................................. 23
2.19. Addition of Surface Layer ................................................................................................... 26
2.19.1. Tolerable Step and Touch Voltage .................................................................................. 27
2.19.2. Conductor Sizing ............................................................................................................. 28
2.19.3. Asymmetrical Currents ................................................................................................... 29
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2.20. Ground Resistance.............................................................................................................. 29
2.21. Maximum Grid Current....................................................................................................... 31
2.22. Ground Potential Rise (GPR) ............................................................................................... 32
2.23. Computing Maximum Step and Mesh Voltages .................................................................. 32
2.23.1. Mesh Voltage (Em) ......................................................................................................... 32
2.23.2. Step Voltage (Es) ............................................................................................................. 36
3. ...................................................................................................... CHAPTER THREE
................................................................................................................................................ 38
3.1. Requirement Analysis and Software Definition .................................................................. 38
3.2. Tools ................................................................................................................................... 39
3.2.1. Microsoft Visual Studio ....................................................................................................... 39
3.2.2. Visual Basic (VB) .................................................................................................................. 39
3.2.3. Word Cleaner 5.0 ................................................................................................................ 41
3.2.4. HTML Help Workshop ......................................................................................................... 41
3.3. Development Plan .............................................................................................................. 42
3.4. Lightning risk assessment ................................................................................................... 42
3.4.1. Structure page ..................................................................................................................... 42
3.4.2. Service lines ......................................................................................................................... 45
3.4.3. Zones ................................................................................................................................... 46
3.4.4. Losses .................................................................................................................................. 48
3.4.4.1. Loss of service to the public:...................................................................................... 50
3.4.4.2. Loss of cultural heritage............................................................................................. 52
3.4.4.3. Loss of Human Life ..................................................................................................... 55
3.4.4.4. Loss of service to the public ....................................................................................... 55
3.4.4.5. Loss of cultural heritage............................................................................................. 55
3.4.5. Risk calculations .................................................................................................................. 56
3.4.6. Risk composition ................................................................................................................. 57
3.4.7. Protection measures ........................................................................................................... 57
3.4.7.1. Reducing RA ............................................................................................................... 59
3.4.7.2. Reducing RB ............................................................................................................... 59
3.4.7.3. Reducing RC ............................................................................................................... 60
3.4.7.4. Reducing RM .............................................................................................................. 61
3.4.7.5. Reducing RU and RV .................................................................................................. 61
3.4.7.6. Reducing RW and RZ .................................................................................................. 62
3.5. Design ................................................................................................................................ 63
3.5.1. GRID DESIGN ....................................................................................................................... 65
3.5.2. Soil Editor ............................................................................................................................ 65
3.5.3. General Design Data ............................................................................................................ 66
3.5.4. Drawing the Grid ................................................................................................................. 68
3.5.5. Earthing grid graphical tool ................................................................................................. 68
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3.6. File ..................................................................................................................................... 69
3.6.1. New ..................................................................................................................................... 69
3.6.2. Open .................................................................................................................................... 69
3.6.3. Save and Save As ................................................................................................................. 69
3.7. Help .................................................................................................................................... 69
3.8. Implementation ................................................................................................................. 70
3.9. Deployment ........................................................................................................................ 70
4. ......................................................................................................... CHAPTER FOUR
................................................................................................................................................ 71
4.1. Lightning Risk Assessment Software Testing ...................................................................... 71
4.1.1. About NTC Tower ................................................................................................................ 71
4.1.2. Relevant data and characteristics ....................................................................................... 73
4.1.3. Calculations ......................................................................................................................... 79
4.1.4. Result Discussion ................................................................................................................. 84
4.2. GRID DESIGN Testing .......................................................................................................... 87
4.3. Results ................................................................................................................................ 88
5. ....................................................................................................... 5 CHAPTER FIVE
................................................................................................................................................ 91
5.1. Conclusion .......................................................................................................................... 91
5.2. Future work ........................................................................................................................ 92
BIBLIOGRAPHY ................................................................................................................. 93
APPENDIX A: ASSESMENT OF NX ................................................................................. A1
APPENDIX B: ASSESMENT OF PX .................................................................................. B1
APPENDIX C: ASSESMENT OF LX .................................................................................. C1
APPENDIX D: MATERIAL CONSTANTS AND EQUIVALENT SUBSTATION
IMPEDANCES ..................................................................................................................... D1
APPENDIX E: LIGHTNING RISK ASSESSMENT SOFTWARE AND GDID DESIGN
SOFTWARE HELP FILES .................................................................................................. E1

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