ELEN7018: EARTHING AND LIGHTNING PROTECTION
Course Project: High Level Design of Earthing and Lightning Protection System for an
Upgrade of a site to Wind and Solar Generation Plant in the Eastern Cape.
Candidate
Student Name
Student Number
XXXXXX
I hereby declare this is my own unaided work, submitted in partial fulfillment for the degree
in Master of Engineering in Electrical
,ELEN7018 Project: High Level Design of Earthing and Lightning Protection System for an Upgrade of
a Site to Wind and Solar Generation Plant in the Eastern Cape
Table of Contents
1
Abstract ......................................................................................................................................... 7
1. INTRODUCTION .................................................................................................................... 8
2. CLASSIFICATION OF STRUCTURE TO BE PROTECTED ................................................... 8
2.1 Sizing of renewable energy ................................................................................................. 9
2.1.1 Wind turbine ................................................................................................................. 9
2.1.2 Photovoltaic ................................................................................................................. 9
2.1.3 Plant layout assumptions ........................................................................................... 10
3. RISK ASSESSMENT AND DETERMINATION OF PROTECTION LEVEL ........................... 11
4. EXTERNAL LIGHTNING PROTECTION SYSTEM (LPS) ..................................................... 14
4.1 Selection of material type for external LPS ........................................................................ 14
4.1.1 Soil resistivity assessment ......................................................................................... 14
4.1.2 Corrosion effect.......................................................................................................... 14
4.1.3 Material dimensions and area of application .............................................................. 15
4.2 Air termination ................................................................................................................... 15
4.2.1 The rolling Sphere method ......................................................................................... 15
4.2.2 The angle protective method ...................................................................................... 16
4.2.3 Mesh size method. ..................................................................................................... 17
4.3 Down conductor system .................................................................................................... 18
4.4 Earth termination system .................................................................................................. 18
4.4.1 Earth electrode arrangement...................................................................................... 18
4.4.2 Foundation of earth electrodes................................................................................... 20
5. INTERNAL LIGHTNING PROTECTION SYSTEM (LPS) ...................................................... 21
5.1 Equipotential bonding for metal installations ..................................................................... 21
5.2 Selection of surge protection devices (SPDs).................................................................... 22
5.2.1 Lightning protection zone (LPZ) boundaries ............................................................... 22
5.2.2 Wind turbines SPDs ................................................................................................... 23
5.2.3 PV arrays and solar generation buildings SPDs ......................................................... 24
5.2.4 Operations and control room SPDs ............................................................................ 25
6. MAINTENANCE ................................................................................................................... 26
7. SOCIOCULTURAL ASPECTS.............................................................................................. 27
8. CONCLUSION...................................................................................................................... 28
Reference .................................................................................................................................... 29
Appendix A: Solar Photovoltaic System Sizing ............................................................................ 30
Appendix B: Risk Assessment Calculations ................................................................................. 32
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XXXXXX
,ELEN7018 Project: High Level Design of Earthing and Lightning Protection System for an Upgrade of
a Site to Wind and Solar Generation Plant in the Eastern Cape
Appendix C: Cables protection measures .................................................................................... 46
Appendix D: Tasks ...................................................................................................................... 50
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XXXXXX
, ELEN7018 Project: High Level Design of Earthing and Lightning Protection System for an Upgrade of
a Site to Wind and Solar Generation Plant in the Eastern Cape
List of Figures
Figure 1: Upgraded Site to Wind and Solar Generation ..................................................................... 8
Figure 2: Wind turbine dimensions [2] ............................................................................................... 9
Figure 3: Solar photovoltaic system, side and front view. ................................................................ 10
Figure 4: Wind turbines and PV system reticulation ........................................................................ 10
Figure 5: Schematic application of the rolling sphere method for wind turbine and PV arrays ......... 16
Figure 6: Protective angle as function of h based on the class of LPL ............................................. 16
Figure 7: Protective angle method applied to PV arrays .................................................................. 17
Figure 8: Building structure protected by mesh size method ........................................................... 17
Figure 9: Type B earth electrode arrangement of the renewable sources site ................................. 19
Figure 10: Minimum length I1 of each earth electrode according to the class of LPS [7] .................. 19
Figure 11: Bonding of services at the boundary [9].......................................................................... 21
Figure 12: Division of wind turbine into different lightning protection zones ..................................... 22
Figure 13: Example - SPDs installed at the zone boundaries of a wind turbine [10] ........................ 23
Figure 14: Example - Lightning protection concept for a PV power plant with central inverter [10] .. 25
Figure 15: Example - SPDs coordination for power and signal cables in the control cable .............. 26
List of Tables
Table 1: Buildings (MCR, CR1, CR2): Risk R1 for the unprotected structure (value 1x10 − 5) ......... 12
Table 2: Buildings (SG1, SG2, SG3) and PV Arrays (PV1, PV2, PV3): Risk R2 for the unprotected
structure (value 1x10 − 3)................................................................................................................ 12
Table 3: a) Buildings (MCR, CR1, CR2): Risk R1 with SPDs of LPL IV ............................................ 13
Table 4: b) Buildings (MCR, CR1, CR2): Risk R1 with SPDs of LPL IV ............................................ 13
Table 5: Relationship between soil resistivity and corrosiveness ..................................................... 14
Table 6: Material dimensions [7]...................................................................................................... 15
Table 7: Material and area of applicability [7] .................................................................................. 15
Table 8: Protection levels for down conductors ............................................................................... 18
Table 9: Structures lightning protection zone (LPZ) boundaries ...................................................... 22
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XXXXXX
Course Project: High Level Design of Earthing and Lightning Protection System for an
Upgrade of a site to Wind and Solar Generation Plant in the Eastern Cape.
Candidate
Student Name
Student Number
XXXXXX
I hereby declare this is my own unaided work, submitted in partial fulfillment for the degree
in Master of Engineering in Electrical
,ELEN7018 Project: High Level Design of Earthing and Lightning Protection System for an Upgrade of
a Site to Wind and Solar Generation Plant in the Eastern Cape
Table of Contents
1
Abstract ......................................................................................................................................... 7
1. INTRODUCTION .................................................................................................................... 8
2. CLASSIFICATION OF STRUCTURE TO BE PROTECTED ................................................... 8
2.1 Sizing of renewable energy ................................................................................................. 9
2.1.1 Wind turbine ................................................................................................................. 9
2.1.2 Photovoltaic ................................................................................................................. 9
2.1.3 Plant layout assumptions ........................................................................................... 10
3. RISK ASSESSMENT AND DETERMINATION OF PROTECTION LEVEL ........................... 11
4. EXTERNAL LIGHTNING PROTECTION SYSTEM (LPS) ..................................................... 14
4.1 Selection of material type for external LPS ........................................................................ 14
4.1.1 Soil resistivity assessment ......................................................................................... 14
4.1.2 Corrosion effect.......................................................................................................... 14
4.1.3 Material dimensions and area of application .............................................................. 15
4.2 Air termination ................................................................................................................... 15
4.2.1 The rolling Sphere method ......................................................................................... 15
4.2.2 The angle protective method ...................................................................................... 16
4.2.3 Mesh size method. ..................................................................................................... 17
4.3 Down conductor system .................................................................................................... 18
4.4 Earth termination system .................................................................................................. 18
4.4.1 Earth electrode arrangement...................................................................................... 18
4.4.2 Foundation of earth electrodes................................................................................... 20
5. INTERNAL LIGHTNING PROTECTION SYSTEM (LPS) ...................................................... 21
5.1 Equipotential bonding for metal installations ..................................................................... 21
5.2 Selection of surge protection devices (SPDs).................................................................... 22
5.2.1 Lightning protection zone (LPZ) boundaries ............................................................... 22
5.2.2 Wind turbines SPDs ................................................................................................... 23
5.2.3 PV arrays and solar generation buildings SPDs ......................................................... 24
5.2.4 Operations and control room SPDs ............................................................................ 25
6. MAINTENANCE ................................................................................................................... 26
7. SOCIOCULTURAL ASPECTS.............................................................................................. 27
8. CONCLUSION...................................................................................................................... 28
Reference .................................................................................................................................... 29
Appendix A: Solar Photovoltaic System Sizing ............................................................................ 30
Appendix B: Risk Assessment Calculations ................................................................................. 32
Page |2
XXXXXX
,ELEN7018 Project: High Level Design of Earthing and Lightning Protection System for an Upgrade of
a Site to Wind and Solar Generation Plant in the Eastern Cape
Appendix C: Cables protection measures .................................................................................... 46
Appendix D: Tasks ...................................................................................................................... 50
Page |3
XXXXXX
, ELEN7018 Project: High Level Design of Earthing and Lightning Protection System for an Upgrade of
a Site to Wind and Solar Generation Plant in the Eastern Cape
List of Figures
Figure 1: Upgraded Site to Wind and Solar Generation ..................................................................... 8
Figure 2: Wind turbine dimensions [2] ............................................................................................... 9
Figure 3: Solar photovoltaic system, side and front view. ................................................................ 10
Figure 4: Wind turbines and PV system reticulation ........................................................................ 10
Figure 5: Schematic application of the rolling sphere method for wind turbine and PV arrays ......... 16
Figure 6: Protective angle as function of h based on the class of LPL ............................................. 16
Figure 7: Protective angle method applied to PV arrays .................................................................. 17
Figure 8: Building structure protected by mesh size method ........................................................... 17
Figure 9: Type B earth electrode arrangement of the renewable sources site ................................. 19
Figure 10: Minimum length I1 of each earth electrode according to the class of LPS [7] .................. 19
Figure 11: Bonding of services at the boundary [9].......................................................................... 21
Figure 12: Division of wind turbine into different lightning protection zones ..................................... 22
Figure 13: Example - SPDs installed at the zone boundaries of a wind turbine [10] ........................ 23
Figure 14: Example - Lightning protection concept for a PV power plant with central inverter [10] .. 25
Figure 15: Example - SPDs coordination for power and signal cables in the control cable .............. 26
List of Tables
Table 1: Buildings (MCR, CR1, CR2): Risk R1 for the unprotected structure (value 1x10 − 5) ......... 12
Table 2: Buildings (SG1, SG2, SG3) and PV Arrays (PV1, PV2, PV3): Risk R2 for the unprotected
structure (value 1x10 − 3)................................................................................................................ 12
Table 3: a) Buildings (MCR, CR1, CR2): Risk R1 with SPDs of LPL IV ............................................ 13
Table 4: b) Buildings (MCR, CR1, CR2): Risk R1 with SPDs of LPL IV ............................................ 13
Table 5: Relationship between soil resistivity and corrosiveness ..................................................... 14
Table 6: Material dimensions [7]...................................................................................................... 15
Table 7: Material and area of applicability [7] .................................................................................. 15
Table 8: Protection levels for down conductors ............................................................................... 18
Table 9: Structures lightning protection zone (LPZ) boundaries ...................................................... 22
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