ELEN7053: POWER ENGINEERING DESIGN PROJECT
Report: Design of a 88kV “Substation F” in Modderfontein and 88 kV
overhead lines to be connected to the newly built 275/88 kV “Substation A”
Substation
Candidate
XXXXX
Student Number
XXXX
Supervisor
XXXXXX
I hereby declare this is my own unaided work, submitted in partial fulfillment for the
degree in Master of Engineering in Electrical
,ELEN7053: Design of an 88kV “Substation F” in Modderfontein and 88kV overhead lines to
be connected to the newly built 275/88 kV Sebenza Substation
Table of Conten
List of Figures....................................................................................................................... 5
List of Tables........................................................................................................................ 6
Acronyms/ Abbreviations and Definitions..........................................................................7
1 Introduction..................................................................................................................... 13
1.1 Background................................................................................................................... 13
1.2 Problem Statement.......................................................................................................13
1.3 Design Objectives........................................................................................................ 16
1.4 Structure of the Report................................................................................................17
2 ““Main Substation F”” and Overhead Line Servitude Data..........................................18
3 Substation Primary Plant Design...................................................................................23
3.1 Substation Insulation Coordination and Clearance...................................................24
3.2 Conductor and Busbar Size Selection........................................................................24
3.2.1 88kV Incomer and Feeder Bays..................................................................................25
3.2.2 88kV Busbar................................................................................................................ 25
3.3 88kV Line Bay Design..................................................................................................25
3.3.1 88kV Feeder Bay Terminal Support Structure.............................................................26
3.3.2 88kV Feeder Bay Isolator (ISO)...................................................................................28
3.3.3 88kV Feeder Bay Surge Arrestor (SA).........................................................................28
3.3.4 88kV Feeder Bay Current Transformer (CT)................................................................28
3.3.5 88kV Feeder Bay Voltage Transformer (VT)................................................................28
3.3.6 88kV Feeder Bay Circuit Breaker (BRKR)...................................................................28
3.4 88kV Busbar Design.....................................................................................................28
3.5 Substation Layout........................................................................................................ 29
4 Substation Control Plant Design....................................................................................31
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,ELEN7053: Design of an 88kV “Substation F” in Modderfontein and 88kV overhead lines to
be connected to the newly built 275/88 kV Sebenza Substation
4.1 Protection Schemes.....................................................................................................32
4.1.1 Protection Schemes IEDs............................................................................................32
4.1.2 Protection Schemes IEDs per Panel............................................................................38
4.1.3 Protection CT Ratios and Class...................................................................................41
4.2 Metering........................................................................................................................ 42
4.2.1 Metering Schemes.......................................................................................................42
4.2.2 MFST – Multi Function SCADA Transducer................................................................45
4.2.3 Metering Schemes per Panel......................................................................................45
4.2.4 Metering CT Ratios and Ratings..................................................................................46
4.3 SCADA/RTU System.....................................................................................................46
4.3.1 Monitoring and Control Philosophy..............................................................................46
4.3.2 Remote Terminal Unit Requirements...........................................................................48
4.4 Telecommunications....................................................................................................49
4.4.1 Multiplexer Equipment.................................................................................................51
4.4.2 Heavy Duty Duct (HDD) Optical Fibre Link..................................................................51
4.4.3 Overhead Power Lines Ground Wire (OPGW) Optical Fibre Link................................52
4.5 AC/DC Supply............................................................................................................... 52
4.5.1 AC Distribution Board..................................................................................................52
4.5.2 Battery Chargers and DC Distribution Board...............................................................54
4.5.3 Batteries...................................................................................................................... 57
4.6 Control and Power Cables...........................................................................................58
5 AEL / “Substation A” 88kV Overhead Line Design.......................................................59
5.1 Overhead Line Insulation Coordination and Clearance.............................................59
5.2 Conductor Selection.....................................................................................................60
5.3 Tower Selection............................................................................................................ 60
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, ELEN7053: Design of an 88kV “Substation F” in Modderfontein and 88kV overhead lines to
be connected to the newly built 275/88 kV Sebenza Substation
6 Lightning Protection System and Earthing Design......................................................62
6.1 Risk Assessment and Determination of Protection Level.........................................62
6.2 External Lightning Protection System (LPS)..............................................................65
6.2.1 Selection of material type for external LPS..................................................................65
6.2.2 Air Termination............................................................................................................ 69
6.2.3 Earth Grid Design........................................................................................................71
6.2.4 Fencing........................................................................................................................ 72
6.2.5 Yard Stoning................................................................................................................ 72
6.3 Internal Lightning Protection System (LPS)...............................................................72
6.3.1 Equipotential bonding for metal installations................................................................74
6.3.2 Selection of surge protection devices (SPDs)..............................................................74
7 Safety, Health, Environmental and Quality....................................................................76
8 Costing............................................................................................................................. 77
References.......................................................................................................................... 78
Annexure A: Overhead Conductor Characteristics and Electrical Clearance...............81
Annexure B: Protection Scheme.......................................................................................82
Annexure C: Metering Scheme..........................................................................................85
Annexure D: SCADA Scheme............................................................................................87
Annexure E: Control and Power Cable Schedules..........................................................98
Annexure F: Risk Assessment Calculations..................................................................103
F.1. Risk Assessment for Unprotected Structures against Lightning Strikes.............105
F.2. Risk Assessment for Protected Structures against Lightning Strikes..................112
Annexure G: Earthing Termination System Design.......................................................121
Annexure G.1: Earth Grid Design Procedure.................................................................121
Annexure G.2: Earth Grid Design Calculations..............................................................122
Annexure G.3: Earth Grid Design Calculations (Iteration 1).........................................124
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Report: Design of a 88kV “Substation F” in Modderfontein and 88 kV
overhead lines to be connected to the newly built 275/88 kV “Substation A”
Substation
Candidate
XXXXX
Student Number
XXXX
Supervisor
XXXXXX
I hereby declare this is my own unaided work, submitted in partial fulfillment for the
degree in Master of Engineering in Electrical
,ELEN7053: Design of an 88kV “Substation F” in Modderfontein and 88kV overhead lines to
be connected to the newly built 275/88 kV Sebenza Substation
Table of Conten
List of Figures....................................................................................................................... 5
List of Tables........................................................................................................................ 6
Acronyms/ Abbreviations and Definitions..........................................................................7
1 Introduction..................................................................................................................... 13
1.1 Background................................................................................................................... 13
1.2 Problem Statement.......................................................................................................13
1.3 Design Objectives........................................................................................................ 16
1.4 Structure of the Report................................................................................................17
2 ““Main Substation F”” and Overhead Line Servitude Data..........................................18
3 Substation Primary Plant Design...................................................................................23
3.1 Substation Insulation Coordination and Clearance...................................................24
3.2 Conductor and Busbar Size Selection........................................................................24
3.2.1 88kV Incomer and Feeder Bays..................................................................................25
3.2.2 88kV Busbar................................................................................................................ 25
3.3 88kV Line Bay Design..................................................................................................25
3.3.1 88kV Feeder Bay Terminal Support Structure.............................................................26
3.3.2 88kV Feeder Bay Isolator (ISO)...................................................................................28
3.3.3 88kV Feeder Bay Surge Arrestor (SA).........................................................................28
3.3.4 88kV Feeder Bay Current Transformer (CT)................................................................28
3.3.5 88kV Feeder Bay Voltage Transformer (VT)................................................................28
3.3.6 88kV Feeder Bay Circuit Breaker (BRKR)...................................................................28
3.4 88kV Busbar Design.....................................................................................................28
3.5 Substation Layout........................................................................................................ 29
4 Substation Control Plant Design....................................................................................31
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,ELEN7053: Design of an 88kV “Substation F” in Modderfontein and 88kV overhead lines to
be connected to the newly built 275/88 kV Sebenza Substation
4.1 Protection Schemes.....................................................................................................32
4.1.1 Protection Schemes IEDs............................................................................................32
4.1.2 Protection Schemes IEDs per Panel............................................................................38
4.1.3 Protection CT Ratios and Class...................................................................................41
4.2 Metering........................................................................................................................ 42
4.2.1 Metering Schemes.......................................................................................................42
4.2.2 MFST – Multi Function SCADA Transducer................................................................45
4.2.3 Metering Schemes per Panel......................................................................................45
4.2.4 Metering CT Ratios and Ratings..................................................................................46
4.3 SCADA/RTU System.....................................................................................................46
4.3.1 Monitoring and Control Philosophy..............................................................................46
4.3.2 Remote Terminal Unit Requirements...........................................................................48
4.4 Telecommunications....................................................................................................49
4.4.1 Multiplexer Equipment.................................................................................................51
4.4.2 Heavy Duty Duct (HDD) Optical Fibre Link..................................................................51
4.4.3 Overhead Power Lines Ground Wire (OPGW) Optical Fibre Link................................52
4.5 AC/DC Supply............................................................................................................... 52
4.5.1 AC Distribution Board..................................................................................................52
4.5.2 Battery Chargers and DC Distribution Board...............................................................54
4.5.3 Batteries...................................................................................................................... 57
4.6 Control and Power Cables...........................................................................................58
5 AEL / “Substation A” 88kV Overhead Line Design.......................................................59
5.1 Overhead Line Insulation Coordination and Clearance.............................................59
5.2 Conductor Selection.....................................................................................................60
5.3 Tower Selection............................................................................................................ 60
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XXXXXXXX
, ELEN7053: Design of an 88kV “Substation F” in Modderfontein and 88kV overhead lines to
be connected to the newly built 275/88 kV Sebenza Substation
6 Lightning Protection System and Earthing Design......................................................62
6.1 Risk Assessment and Determination of Protection Level.........................................62
6.2 External Lightning Protection System (LPS)..............................................................65
6.2.1 Selection of material type for external LPS..................................................................65
6.2.2 Air Termination............................................................................................................ 69
6.2.3 Earth Grid Design........................................................................................................71
6.2.4 Fencing........................................................................................................................ 72
6.2.5 Yard Stoning................................................................................................................ 72
6.3 Internal Lightning Protection System (LPS)...............................................................72
6.3.1 Equipotential bonding for metal installations................................................................74
6.3.2 Selection of surge protection devices (SPDs)..............................................................74
7 Safety, Health, Environmental and Quality....................................................................76
8 Costing............................................................................................................................. 77
References.......................................................................................................................... 78
Annexure A: Overhead Conductor Characteristics and Electrical Clearance...............81
Annexure B: Protection Scheme.......................................................................................82
Annexure C: Metering Scheme..........................................................................................85
Annexure D: SCADA Scheme............................................................................................87
Annexure E: Control and Power Cable Schedules..........................................................98
Annexure F: Risk Assessment Calculations..................................................................103
F.1. Risk Assessment for Unprotected Structures against Lightning Strikes.............105
F.2. Risk Assessment for Protected Structures against Lightning Strikes..................112
Annexure G: Earthing Termination System Design.......................................................121
Annexure G.1: Earth Grid Design Procedure.................................................................121
Annexure G.2: Earth Grid Design Calculations..............................................................122
Annexure G.3: Earth Grid Design Calculations (Iteration 1).........................................124
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