Design of Shipboard Power System Grounding / Earthing

Norbert Doerry, PhD, is a naval engineer with a PhD in naval electrical power systems and with over 35 years of experience in innovation, invention, science and technology, research and development acquisition, design, construction, in-service support, and ship operations.Mohammed M. Islam currently serves as the Chair of IEEE 45.7 Switchboard Standard working group. He has been involved in the "All Electric Ship Design and Development" and R&D programs for many years. He was the principal investigator of the Ship Smart-System Design (S3D) feasibility study, an ONR funded resaerch and development project. He was the R&D manager of Ship System Applied Science at Northrop Grumman Ship Systems. He served as the IEEE-45 central committee chair and chair of numerous IEEE 45 series Standards.John Prousalidis, PhD, is a Professor with the Academic Staff of the School of naval Architecture and Marine Engineering. He is a reviewer of IEEE and IET journal papers, a member of the Editorial Board of the IET journal Power Systems in Transportation, and of the International Journal of Ocean Systems Management (IJOSM) of Indersience Publishers.

• About the Authors xiiiPreface xv1 Introduction 11.1 General 11.2 Grounding and Earthing Definitions 21.3 Common Mode Terminology 41.4 Types of Power Distribution Systems 51.5 Types of Power System Grounding Systems 71.6 Modeling and Simulation 81.7 Book Overview 91.8 Legal Notice 13References 132 System Grounding: Shipboard Ungrounded AC Systems (No Greater than 1 kV) 152.1 Characteristics 152.2 Modeling Shipboard Ungrounded AC Low-Voltage Distribution Systems 192.2.1 Low-Voltage AC Cable Model 202.2.2 Bus Duct 252.2.3 EMI Filters 252.2.4 Generators and Motors 252.2.5 Transformers 262.2.6 System Simulation 262.3 Ground Fault Detection 292.4 Ground Fault Localization 372.5 Electrical Insulation Impacts 412.6 One-Line Diagram Symbology 412.7 Case Studies 422.7.1 Modeling a Low-Voltage AC Cable 422.7.2 Modeling a Cable Line-to-Line Capacitance for GFCI Calculations 442.8 Reference Cable Data 49References 533 System Grounding: Shipboard HRG AC Low-Voltage Distribution Systems (No Greater than 1 kV) 553.1 Characteristics 553.2 Grounding Circuit 643.2.1 Grounding Resistor Characteristics 643.2.2 Neutral Ground 663.2.3 Zigzag Transformer 663.2.4 Wye-Delta Transformer 673.2.5 Wye-Broken Delta Transformer 683.2.6 One-Line Diagram Symbology 693.2.7 Grounding Transformer Characteristics 703.2.8 Grounding Transformer Saturation 703.3 Location of Grounding Circuit 743.4 Ground Fault Detection 783.5 Ground Fault Localization 793.5.1 Pulsing System 793.5.2 Low-Resistance Ground Fault Clearing 803.5.3 Common Mode Current Phase Measurements 823.6 Electrical Insulation Impacts 833.7 Limiting Ground Fault Current 83References 844 System Grounding: Shipboard Solidly Grounded AC Systems (No Greater than 400 V) 854.1 Characteristics 854.2 Design Considerations 894.2.1 General 894.2.2 Transformers 894.2.3 Sub-power Panels 944.2.4 Ground Fault Protection 944.3 Cable Insulation Colors 975 System Grounding: Shipboard HRG AC Primary Distribution Systems (Greater than 1 kV) 995.1 Characteristics 995.2 Grounding Circuit 1005.2.1 Grounding Resistor Transformer 1005.2.2 Wye-Broken Delta Transformer 1015.2.3 Grounding Resistor Design 1025.3 Modeling Shipboard HRG AC Primary Distribution Systems 1025.3.1 Three-Conductor Shielded Cable Models 1025.3.2 Single-Conductor Cable and Insulated Bus Pipe Models 1075.3.3 EMI and Harmonic Filters 1095.3.4 Generators and Motors 1095.3.5 Transformers 1125.3.6 System Simulation 1145.4 Location of Grounding Circuit 1175.5 Ground Fault Detection 1185.6 Ground Fault Localization 1185.7 Electrical Insulation Impact 1195.7.1 Insulation Voltage Rating 1195.7.2 Partial Discharge 1195.8 Limiting Ground Fault Current 1205.9 Cable Terminations 120References 1226 System Grounding: Shipboard Ungrounded DC Systems (No Greater than 1 kV) 1256.1 Characteristics 1256.2 Modeling 1286.2.1 Two-Conductor Unshielded Cable 1286.2.2 Four-Conductor Unshielded Cable 1316.2.3 Passive Rectifiers 1336.2.4 Active Rectifiers 1336.3 Ground Fault Detection 1336.4 Ground Fault Localization 1366.5 Auctioneering Diodes 1406.6 Electrical Insulation Impacts 1436.7 Cable Insulation Colors 143References 1437 System Grounding: Shipboard HRG DC Systems 1457.1 Characteristics 1457.2 Grounding Methods 1467.2.1 Line-to-Ground Resistors 1467.2.2 Split Power Supply 1497.2.3 Grounding Bus 1507.2.4 Current Sensors 1507.3 Modeling 1517.3.1 Four-Conductor Shielded Cable 1517.4 Ground Fault Detection 1547.5 Ground Fault Localization 1547.6 Electrical Insulation Impacts 1587.6.1 Insulation Voltage Rating 1587.6.2 Partial Discharge 1587.6.3 Space Charge 159References 1598 System Grounding: Shipboard Solidly Grounded DC Systems (No Greater than 1 kV) 1618.1 Characteristics 1618.2 Corrosion 1638.3 Modeling Shipboard Solidly Grounded DC Systems 1638.4 Ground Fault Detection and Localization 1648.5 Electrical Insulation Impacts 1668.6 Cable Insulation Colors 1669 Designing Shipboard Power System Grounding/Earthing Systems 1679.1 Introduction 1679.2 AC Primary Distribution Systems 1689.3 AC Low-Voltage Distribution Systems 1709.4 AC Low-Voltage Secondary Distribution Systems 1719.5 AC Low-Voltage Special Circuits 1729.6 dc Primary Distribution Systems 1729.7 dc Low-Voltage Distribution Systems 1739.8 dc Low-Voltage Secondary Distribution Systems 1739.9 dc Low-Voltage Special Circuits 1749.10 Examples 1749.10.1 AC Low-Voltage Distribution System for Commercial Mechanical Drive Ship 1749.10.2 AC Primary Distribution System for Commercial Integrated Power System Ship 1809.10.3 Low-Voltage AC Zonal Distribution 1859.10.4 Zonal AC Primary Distribution 1859.10.5 Commercial Ship DC Distribution 1909.10.6 Zonal DC Primary Distribution 192References 19310 Power Conversion Equipment Grounding 19510.1 Introduction 19510.2 Transformers 19510.3 Isolated Power Conversion Equipment 19810.4 Non-Isolated Power Conversion Equipment 19910.5 cm Voltage and Current Control 20110.6 VFD Cable 20210.6.1 VFD Cable Description and Use 20210.6.2 VFD Cable Modeling (Without Conductor Shields) 20510.6.3 VFD Cable Modeling (with Conductor Shields) 20810.7 Examples 20910.7.1 Directly Connected VFD and Motor – No More than 1 kV 20910.7.2 Transformer-Supplied VFD and Motor – No Greater than 1 kV 21210.7.3 Propulsion Motor Drives – Greater than 1 kV 21410.8 Maintenance Considerations 217References 21911 Shore Power (Cold Ironing) Connection Grounding 22111.1 Introduction 22111.2 Low-Voltage Shore Connections 22311.3 High-Voltage Shore Connections 227References 23712 Vehicle Connections Grounding 23912.1 Introduction 23912.2 Design Considerations 23912.2.1 Aircraft Static Electricity 23912.2.2 Vehicle Electrical Systems 241References 24213 Common Mode Grounding: Impact of Common Mode Currents and Voltages on Grounding Systems 24313.1 Common Mode Fundamentals 24313.2 Relationship of CM to EMI and EMC 25613.3 Control of CM Currents and Voltages 25713.3.1 Equipment Design 25813.3.2 Cable Shields, Drain Wires, and Ground Conductors 25813.3.3 Inductors and CM Chokes 26113.3.4 Capacitors and CM Shunts 26413.3.5 cm Control Philosophies 26713.3.5.1 Cable Only Solution 26713.3.5.2 Cable and CM Choke Solution 26813.3.5.3 Controlling CM at the Interfaces 26813.3.5.4 Controlling CM at the HRG 27013.3.5.5 Controlling CM Within Motors and Generators 27013.3.6 cm AC Limits 27113.3.7 cm dc Limits 27313.4 Advanced CM Modeling 27513.5 Design Considerations 276References 27614 Protective Earthing: Bonding 27914.1 Introduction 27914.2 Design Considerations 28014.3 Testing 286References 28615 Current-Related Corrosion 28915.1 Introduction 28915.2 Galvanic Corrosion Theory 28915.3 Impact of Current on Galvanic Corrosion 29615.3.1 dc Current 29615.3.2 AC Current 29715.4 Shipboard Corrosion 29715.4.1 Hull and Structure Corrosion 29715.4.2 Propulsion Shaft Corrosion 29815.4.3 Electrical Connection Corrosion 29915.4.4 Bearing Corrosion 29915.5 Cathodic Protection Systems 30015.5.1 Sacrificial Anodes 30015.5.2 Impressed Current Cathodic Protection 302References 30316 Lightning Protection Systems 30516.1 Introduction 30516.2 Design Considerations 30816.2.1 Zone of Protection 30816.2.2 Air Terminals 31016.2.3 Down Conductors 31116.2.4 Low-Impedance Ground Connection 31216.2.5 Surge Protection 312References 31417 Grounding Systems for Nonmetallic Hull Ships 31717.1 Design Considerations 317Reference 319Appendix A Glossary 321Appendix B Acronyms and Abbreviations 337Appendix C Impact of Electric Current on Humans 339Index 345