Design of Shipboard Power System Grounding / Earthing E-Book

Norbert Doerry

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 429

Veröffentlichungsjahr: 2024

Beschreibung

This book delves into the diverse prerequisites for grounding and earthing in contemporary ship power systems, addressing the evolving landscape of ship design influenced by power electronics

The introduction of transformative technologies such as variable frequency drives and electric propulsion systems has heightened the complexity of shipboard grounding systems. This complexity necessitates accommodation for robust electronic systems, extending the focus beyond traditional grounding aspects to include common mode grounding and its profound design implications. Engineers now require a comprehensive guide to navigate the intricacies of shipboard electric power systems.

To meet this imperative, Design of Shipboard Power System Grounding/Earthing provides an in-depth exploration of the subject. It offers a step-by-step initiation into the grounding process, supported by numerous case studies for enhanced comprehension. Aligned with both US and international standards, this book serves as an essential resource for engineers engaged in the design and implementation of shipboard power systems.

Key highlights for readers encompass meticulous comparisons between terrestrial power system grounding and shipboard power grounding, as well as comprehensive discussions on high resistance grounding, shipboard AC system grounding requirements, DC system grounding, and more, including common mode grounding and earthing. The inclusion of abundant engineering drawings supports significant case studies, enhancing the practical application of the material.

Designed to cater to a broad audience, Design of Shipboard Power System Grounding/Earthing is invaluable for readers involved with shipboard electrical systems, including shipbuilders, ship designers, ship operators, and those in regulatory bodies such as the Navy, USCG, ABS, among others. This resource is also well-suited for academicians, particularly final-year undergraduate and graduate students in marine electrical engineering programs.

Leseprobe

Table of Contents

Cover

Table of Contents

Series Page

Title Page

Copyright Page

About the Authors

Preface

1 Introduction

1.1 General

1.2 Grounding and Earthing Definitions

1.3 Common Mode Terminology

1.4 Types of Power Distribution Systems

1.5 Types of Power System Grounding Systems

1.6 Modeling and Simulation

1.7 Book Overview

1.8 Legal Notice

References

2 System Grounding: Shipboard Ungrounded AC Systems (No Greater than 1 kV)

2.1 Characteristics

2.2 Modeling Shipboard Ungrounded AC Low‐Voltage Distribution Systems

2.3 Ground Fault Detection

2.4 Ground Fault Localization

2.5 Electrical Insulation Impacts

2.6 One‐Line Diagram Symbology

2.7 Case Studies

2.8 Reference Cable Data

References

3 System Grounding: Shipboard HRG AC Low‐Voltage Distribution Systems (No Greater than 1 kV)

3.1 Characteristics

3.2 Grounding Circuit

3.3 Location of Grounding Circuit

3.4 Ground Fault Detection

3.5 Ground Fault Localization

3.6 Electrical Insulation Impacts

3.7 Limiting Ground Fault Current

References

4 System Grounding: Shipboard Solidly Grounded AC Systems (No Greater than 400 V)

4.1 Characteristics

4.2 Design Considerations

4.3 Cable Insulation Colors

5 System Grounding: Shipboard HRG AC Primary Distribution Systems (Greater than 1 kV)

5.1 Characteristics

5.2 Grounding Circuit

5.3 Modeling Shipboard HRG AC Primary Distribution Systems

5.4 Location of Grounding Circuit

5.5 Ground Fault Detection

5.6 Ground Fault Localization

5.7 Electrical Insulation Impact

5.8 Limiting Ground Fault Current

5.9 Cable Terminations

References

6 System Grounding: Shipboard Ungrounded DC Systems (No Greater than 1 kV)

6.1 Characteristics

6.2 Modeling

6.3 Ground Fault Detection

6.4 Ground Fault Localization

6.5 Auctioneering Diodes

6.6 Electrical Insulation Impacts

6.7 Cable Insulation Colors

References

7 System Grounding: Shipboard HRG DC Systems

7.1 Characteristics

7.2 Grounding Methods

7.3 Modeling

7.4 Ground Fault Detection

7.5 Ground Fault Localization

7.6 Electrical Insulation Impacts

References

8 System Grounding: Shipboard Solidly Grounded DC Systems (No Greater than 1 kV)

8.1 Characteristics

8.2 Corrosion

8.3 Modeling Shipboard Solidly Grounded DC Systems

8.4 Ground Fault Detection and Localization

8.5 Electrical Insulation Impacts

8.6 Cable Insulation Colors

9 Designing Shipboard Power System Grounding/Earthing Systems

9.1 Introduction

9.2 AC Primary Distribution Systems

9.3 AC Low‐Voltage Distribution Systems

9.4 AC Low‐Voltage Secondary Distribution Systems

9.5 AC Low‐Voltage Special Circuits

9.6 DC Primary Distribution Systems

9.7 DC Low‐Voltage Distribution Systems

9.8 DC Low‐Voltage Secondary Distribution Systems

9.9 DC Low‐Voltage Special Circuits

9.10 Examples

References

10 Power Conversion Equipment Grounding

10.1 Introduction

10.2 Transformers

10.3 Isolated Power Conversion Equipment

10.4 Non‐Isolated Power Conversion Equipment

10.5 CM Voltage and Current Control

10.6 VFD Cable

10.7 Examples

10.8 Maintenance Considerations

References

11 Shore Power (Cold Ironing) Connection Grounding

11.1 Introduction

11.2 Low‐Voltage Shore Connections

11.3 High‐Voltage Shore Connections

References

12 Vehicle Connections Grounding

12.1 Introduction

12.2 Design Considerations

References

13 Common Mode Grounding: Impact of Common Mode Currents and Voltages on Grounding Systems

13.1 Common Mode Fundamentals

13.2 Relationship of CM to EMI and EMC

13.3 Control of CM Currents and Voltages

13.4 Advanced CM Modeling

13.5 Design Considerations

References

14 Protective Earthing: Bonding

14.1 Introduction

14.2 Design Considerations

14.3 Testing

References

15 Current‐Related Corrosion

15.1 Introduction

15.2 Galvanic Corrosion Theory

15.3 Impact of Current on Galvanic Corrosion

15.4 Shipboard Corrosion

15.5 Cathodic Protection Systems

References

16 Lightning Protection Systems

16.1 Introduction

16.2 Design Considerations

References

17 Grounding Systems for Nonmetallic Hull Ships

17.1 Design Considerations

Reference

Appendix A: Glossary

Appendix B: Acronyms and Abbreviations

Appendix C: Impact of Electric Current on Humans

C.1 Introduction

C.2 Low‐Frequency (60 Hz) Currents

C.3 DC Currents

C.4 High‐Frequency Currents

References

Index

End User License Agreement

List of Tables

Chapter 1

Table 1.1 Recommended grounding methods.

Chapter 2

Table 2.1 Cable dimensions for LSTSGU cable.

Table 2.2 Cable electrical data for LSTSGU cable.

Chapter 4

Table 4.1 Conductor insulation colors for AC voltages no greater than 240 V....

Chapter 5

Table 5.1 Estimates for line‐to‐ground capacitance (per phase) of 13.8 kV ca...

Table 5.2 Estimates for line‐to‐ground capacitance (per phase) of medium vol...

Chapter 9

Table 9.1 Recommended grounding methods.

Chapter 11

Table 11.1 IEC/IEC 80005‐1 (2019) ship‐to‐shore connection details by ship t...

Chapter 15

Table 15.1 Galvanic series.

Chapter 16

Table 16.1 Properties of materials to determine if down conductor should be ...

List of Illustrations

Chapter 1

Figure 1.1 Ground symbols: (a) IEC Symbol 5017, (b) IEC Symbol 5018, (c) IEC...

Figure 1.2 Ground symbols used in this book: (a) system ground, (b) protecti...

Figure 1.3 Use of ground symbols.

Figure 1.4 Relationships among shipboard power distribution systems.

Chapter 2

Figure 2.1 Applicability of ungrounded AC power systems.

Figure 2.2 Ungrounded three‐phase AC system with delta generator or transfor...

Figure 2.3 Path of ground fault current in an ungrounded system (wye source)...

Figure 2.4 Supplying single‐phase loads with (a) a three‐phase four‐wire tra...

Figure 2.5 Low‐voltage three‐phase AC unshielded cable geometry.

Figure 2.6 Dynamic model of a low‐voltage three‐phase AC unshielded cable fo...

Figure 2.7 (a) LTspice simple model of an ungrounded system with ground faul...

Figure 2.8 Line‐to‐ground phase voltages in an ungrounded system with ground...

Figure 2.9 Current through ground fault in an ungrounded system.

Figure 2.10 Impact of intermittent ground fault on an ungrounded system.

Figure 2.11 LTspice model to determine the impact of arc ground fault on an ...

Figure 2.12 Impact of arc ground fault on an ungrounded system: (a) phase

a

;...

Figure 2.13 Impact of not modeling the cable with a mutual inductance.

Figure 2.14 Lamp‐based ground detection system.

Figure 2.15 Ground fault detection panel display.

Figure 2.16 LTspice model of an ungrounded three‐phase AC system feeding a p...

Figure 2.17 Rectifier output voltage (shaded area corresponds to one cycle)....

Figure 2.18 Rectifier AC phase current.

Figure 2.19 Rectifier AC line‐to‐line voltage.

Figure 2.20 Line‐to‐ground voltage of AC system feeding a passive rectifier ...

Figure 2.21 Line‐to‐ground phase voltages with stuck bus‐tie breaker contact...

Figure 2.22 Insulation monitoring device panel meter.

Figure 2.23 Clamp‐on current meter.

Figure 2.24 LTspice model of a system with one generator feeder and three lo...

Figure 2.25 CM current at each feeder cable (feeder 2 is faulted).

Figure 2.26 CM current of feeder before and after the fault location.

Figure 2.27 One‐line diagram symbols for ground detection system, ground det...

Figure 2.28 Secondary distribution system (120 V single‐phase) with GFCI and...

Figure 2.29 Secondary distribution system (120 V single‐phase) with GFCI and...

Figure 2.30 Secondary distribution system (120 V three‐phase from delta seco...

Figure 2.31 Secondary distribution system (120 V three‐phase from wye second...

Figure 2.32 Secondary distribution system (120 V three‐phase from wye second...

Chapter 3

Figure 3.1 Applicability of high‐resistance grounded AC low‐voltage distribu...

Figure 3.2 HRG three‐phase AC system with delta generator or transformer.

Figure 3.3 HRG with grounding transformer and grounding resistor (grounding ...

Figure 3.4 Three‐phase AC system with wye generator or transformer and NGR....

Figure 3.5 NGR with instrumentation.

Figure 3.6 Path of ground fault current in a HRG system using an NGR.

Figure 3.7 LTspice model of an HRG system using NGR with ground fault.

Figure 3.8 Line‐to‐ground phase voltages in an HRG system using NGR with gro...

Figure 3.9 Current through the ground fault in an HRG system using NGR.

Figure 3.10 Current through the grounding resistor in an HRG system using NG...

Figure 3.11 Line‐to‐line voltages during the ground fault in an HRG system u...

Figure 3.12 Line‐to‐ground voltages during ground fault with high EMI capaci...

Figure 3.13 Current through the NGR during ground fault with high EMI capaci...

Figure 3.14 Impact of intermittent ground fault on an HRG system with NGR.

Figure 3.15 Impact of arc fault on a HRG system with NGR.

Figure 3.16 Zigzag transformer HRG configuration.

Figure 3.17 Zigzag transformer HRG grounding circuit.

Figure 3.18 Wye‐delta transformer HRG configuration.

Figure 3.19 Wye‐delta transformer HRG grounding circuit.

Figure 3.20 Wye‐broken delta transformer HRG configuration.

Figure 3.21 Wye‐broken delta transformer HRG grounding circuit.

Figure 3.22 (a) HRG circuit on the bus one‐line diagram symbol; (b) NGR on t...

Figure 3.23 LTspice model of an AC HRG power system with rectifier load sche...

Figure 3.24 AC HRG system with rectifier load phase voltages – ground fault ...

Figure 3.25 AC HRG system with rectifier load line‐to‐line voltages – ground...

Figure 3.26 AC HRG system with rectifier grounding resistor current – ground...

Figure 3.27 Grounding transformers with blocking capacitors (a) zigzag; (b) ...

Figure 3.28 Blocking capacitor network.

Figure 3.29 Grounding resistor current with blocking capacitor network due t...

Figure 3.30 Blocking capacitor network voltage due to DC ground fault.

Figure 3.31 Line‐to‐ground voltages (phase

a

) due to DC ground fault with bl...

Figure 3.32 LTspice model of three‐feeder system with pulsing system for gro...

Figure 3.33 CM current on feeder 1.

Figure 3.34 CM current on feeder 2 (a) before the ground fault; (b) after th...

Figure 3.35 CM current on feeder 3.

Figure 3.36 CM current through each feeder cable of Figure 3.32.

Chapter 4

Figure 4.1 Applicability of an AC solidly grounded low‐voltage distribution ...

Figure 4.2 Solidly grounded single‐phase 120/208 V from three‐phase four‐wir...

Figure 4.3 Solidly grounded single‐phase 120/240 V and 240 V from single‐pha...

Figure 4.4 Ground detection current meter showing indication of ground fault...

Figure 4.5 LTspice model of delta‐wye transformer with secondary solidly gro...

Figure 4.6 Secondary phase currents for delta‐wye transformer with secondary...

Figure 4.7 LTspice model of wye‐wye transformer with secondary solidly groun...

Figure 4.8 Secondary phase currents for wye‐wye transformer with secondary s...

Figure 4.9 Secondary phase voltages for wye‐wye transformer with secondary s...

Figure 4.10 120/208 V load voltages for wye‐wye transformer with secondary s...

Figure 4.11 LTspice model of wye‐wye transformer with secondary solidly grou...

Figure 4.12 Secondary phase currents for wye‐wye transformer with secondary ...

Figure 4.13 Secondary line‐to‐line voltages for wye‐wye transformer with sec...

Figure 4.14 Secondary phase voltages for wye‐wye transformer with secondary ...

Figure 4.15 Fault current for wye‐wye transformer with secondary solidly gro...

Figure 4.16 Solidly grounded systems with power panel and sub‐power panel.

Figure 4.17 Solidly grounded systems with GFCI.

Chapter 5

Figure 5.1 Applicability of HRG AC primary distribution systems.

Figure 5.2 Use of transformer for grounding resistor.

Figure 5.3 Use of transformer for grounding resistor with zigzag transformer...

Figure 5.4 Wye‐broken delta transformer configuration.

Figure 5.5 Wye‐broken delta transformer grounding circuit.

Figure 5.6 Three‐phase shielded cable dimensions.

Figure 5.7 Schematic for cable model for shielded cable depicted in Figure 5...

Figure 5.8 Insulated bus pipe with shield cross‐section view.

Figure 5.9 Triad arrangement for a set of single‐conductor shielded cables o...

Figure 5.10 Single‐bank arrangement for a set of shielded single‐conductor s...

Figure 5.11 Schematic for cable model.

Figure 5.12 Phase‐to‐ground capacitance for salient‐pole generators and moto...

Figure 5.13 Estimated capacitance‐to‐ground per phase of turbine generator (...

Figure 5.14 Estimated capacitance‐to‐ground per phase of 2.3 kV synchronous ...

Figure 5.15 Estimated capacitance‐to‐ground per phase of 2.3 kV induction mo...

Figure 5.16 LTspice model of an AC primary distribution system with HRG syst...

Figure 5.17 Phase voltages at the generator terminals with phase

a

ground fa...

Figure 5.18 Phase voltages at the fault with phase

a

ground fault.

Figure 5.19 Phase voltages at the load with phase

a

ground fault.

Figure 5.20 Cable termination at the load end of an AC primary distribution ...

Figure 5.21 Cable terminations at the generator end of an AC primary distrib...

Chapter 6

Figure 6.1 Applicability of ungrounded DC power systems.

Figure 6.2 Line‐to‐ground voltages and neutral‐to‐ground voltages of a groun...

Figure 6.3 Ground fault current with ground fault from 0.5 to 1.0 seconds fo...

Figure 6.4 Two‐conductor ungrounded cable with ground fault from 1.1 to 1.2 ...

Figure 6.5 Two‐conductor ungrounded cable recovery from ground fault from 1....

Figure 6.6 LTspice model of two‐conductor ungrounded cable with ground fault...

Figure 6.7 Two‐conductor unshielded DC cable.

Figure 6.8 Unshielded DC cable transient model.

Figure 6.9 Four‐conductor unshielded DC cable.

Figure 6.10 LTspice model of an ungrounded DC system powered from passive re...

Figure 6.11 Ungrounded DC system powered from passive rectifier – voltages a...

Figure 6.12 Ungrounded DC system powered from passive rectifier – current th...

Figure 6.13 Ungrounded DC system powered from passive rectifier – CM current...

Figure 6.14 DC ground lights in an ungrounded DC power system.

Figure 6.15 LTspice model of a passive rectifier‐based ungrounded DC system ...

Figure 6.16 Passive rectifier‐based DC system CM current of three feeders (C...

Figure 6.17 Passive rectifier‐based DC system CM current on faulted feeder (...

Figure 6.18 Passive rectifier‐based DC system CM current on un‐faulted feede...

Figure 6.19 Passive rectifier‐based DC system CM current on faulted feeder b...

Figure 6.20 Passive rectifier‐based DC system CM voltage and line‐to‐line vo...

Figure 6.21 Passive rectifier‐based DC system CM voltages at bus and at wye ...

Figure 6.22 Asymmetric auctioneering diode configuration with multiple retur...

Figure 6.23 Symmetric auctioneering diode configuration with single return c...

Figure 6.24 Symmetric auctioneering diodes configuration with double ground ...

Figure 6.25 Modified symmetric auctioneering diodes configuration.

Chapter 7

Figure 7.1 Applicability of HRG DC power systems.

Figure 7.2 Schematic of HRG system for DC.

Figure 7.3 Line‐to‐ground and neutral‐to‐ground voltages at the load.

Figure 7.4 Current through the ground fault. (a) Complete waveform; (b) init...

Figure 7.5 Current through the grounding resistor.

Figure 7.6 DC line‐to‐ground resistors.

Figure 7.7 Split power supply.

Figure 7.8 Four‐conductor shielded DC cable.

Figure 7.9 Shielded DC cable transient model.

Figure 7.10 Voltages of positive and negative conductors, and neutral voltag...

Figure 7.11 Grounding resistor current of three‐feeder system with ground fa...

Figure 7.12 CM current of each of the three feeders.

Figure 7.13 CM current at the source and load on each of the feeders. (a) Ca...

Figure 7.14 Schematic of DC circuit with three feeders.

Figure 7.15 Voltages of positive and negative conductors, and neutral voltag...

Figure 7.16 Grounding resistor current of three‐feeder system with high volt...

Figure 7.17 CM current of each of the three feeders for a system with high v...

Figure 7.18 CM current on the feeder at the DC bus and at the load with high...

Chapter 8

Figure 8.1 Applicability of solidly grounded DC systems.

Figure 8.2 Solidly grounded DC power system with grounded negative conductor...

Figure 8.3 Solidly grounded two‐wire DC power system with split power supply...

Figure 8.4 Solidly grounded three‐wire DC power system with split power supp...

Figure 8.5 LTspice model of a ground fault on the grounded conductor of a tw...

Figure 8.6 CM current due to ground fault on the grounded conductor of a two...

Figure 8.7 LTspice model of a ground fault on the “hot” conductor of a two‐w...

Figure 8.8 CM current due to high‐resistance ground fault on “hot” conductor...

Figure 8.9 Phase currents due to low‐resistance ground fault on “hot” conduc...

Chapter 9

Figure 9.1 Line‐to‐ground voltages for 1 and 12 kV HRG systems that are (a) ...

Figure 9.2 Shipboard power system for a mechanical drive ship with low ship ...

Figure 9.3 HRG circuit using a zigzag transformer with grounding switch.

Figure 9.4 Generator NGR with grounding switch: (a) separate NGR cabinet; (b...

Figure 9.5 Shipboard power system for a mechanical drive ship with low ship ...

Figure 9.6 Shipboard power system for an IPS ship with HRG circuits.

Figure 9.7 Shipboard power system for an IPS ship with NGRs.

Figure 9.8 Shipboard power system for an IPS ship with grounding buses.

Figure 9.9 Low‐voltage AC zonal distribution system.

Figure 9.10 Zonal AC primary distribution system with HRG in generator switc...

Figure 9.11 Zonal AC primary distribution system with HRG in zonal switchboa...

Figure 9.12 Commercial ship DC distribution system – integrated converters....

Figure 9.13 Commercial ship DC distribution system – separate converters.

Figure 9.14 Zonal DC primary distribution system.

Chapter 10

Figure 10.1 Three‐phase transformer configurations: (a) delta‐delta; (b) del...

Figure 10.2 Isolated power conversion equipment architectures for AC loads: ...

Figure 10.3 Isolated power conversion equipment architectures for DC loads: ...

Figure 10.4 Non‐isolated power conversion equipment architectures for AC loa...

Figure 10.5 Non‐isolated power conversion equipment architectures for DC loa...

Figure 10.6 VFD cable showing main conductors (without conductor shields) an...

Figure 10.7 VFD cable showing cable shields, main conductors, and drain wire...

Figure 10.8 Grounding of VFD cable drain wires and shields: (a) without cond...

Figure 10.9 Geometry of VFD cable without conductor shields.

Figure 10.10 Cable transient model: (a) detailed; (b) simplified.

Figure 10.11 Geometry of VFD cable with conductor shields.

Figure 10.12 Simplified model of VFD cable with conductor shields.

Figure 10.13 Low‐voltage VFD and motor.

Figure 10.14 Low‐voltage VFD and motor with supply‐side CM choke.

Figure 10.15 Low‐voltage VFD with supply‐side and load‐side CM chokes.

Figure 10.16 Low‐voltage VFD and motor with supply‐side and load‐side CM shu...

Figure 10.17 Low‐voltage VFD and motor using line reactors to limit CM curre...

Figure 10.18 Transformer‐isolated low‐voltage VFD and motor.

Figure 10.19 Transformer‐isolated low‐voltage VFD and motor with CM shunt.

Figure 10.20 Transformer‐isolated low‐voltage VFD and motor with NGR.

Figure 10.21 Twelve‐pulse rectifier constructed from two six‐pulse rectifier...

Figure 10.22 Twelve‐pulse rectifiers for double stator winding motor in para...

Figure 10.23 Twelve‐pulse rectifier constructed from two six‐pulse rectifier...

Figure 10.24 Twelve‐pulse rectifier with HRG circuit in parallel (greater th...

Figure 10.25 Example HRG circuit.

Figure 10.26 AVT control unit, cable, and display.

Figure 10.27 Combination AVT and voltage test indicator.

Chapter 11

Figure 11.1 Shore‐to‐ship connection using cables.

Figure 11.2 Sailors manually disconnecting shore power cables.

Figure 11.3 Shore‐to‐ship connection using a cable handling system.

Figure 11.4 IEC/IEEE DIS 80005‐3 example LVSC ship‐to‐shore connection.

Figure 11.5 IEC/IEEE DIS 80005‐3 example LVSC ship‐to‐shore connection plug ...

Figure 11.6 Shipboard shore power switchboard for naval applications.

Figure 11.7 Sailor connecting shore power to naval warship.

Figure 11.8 Equipotential bond monitoring between shore and ship using pilot...

Figure 11.9 Example shore station with transformer for cruise ships.

Figure 11.10 Example cruise ship onboard shore connection switchboard.

Figure 11.11 Example shore station with frequency changer for cruise ships....

Figure 11.12 Example shore station with transformer for roll‐on/roll‐off car...

Figure 11.13 Example roll‐on/roll‐off cargo or roll‐on/roll‐off passenger sh...

Figure 11.14 Sailors working on a medium‐voltage shore connection box.

Chapter 12

Figure 12.1 Helicopter static discharge wand.

Figure 12.2 A marine holds a static discharge wand against the cargo hook of...

Figure 12.3 Use of control pins on the power cable connector to control the ...

Chapter 13

Figure 13.1 Schematic of six‐pulse rectifier.

Figure 13.2 DC conductor voltages and DC neutral voltage with respect to AC ...

Figure 13.3 DC conductor voltages and AC neutral voltage with respect to DC ...

Figure 13.4 DM voltage and current for six‐pulse rectifier.

Figure 13.5 CM voltage and current for six‐pulse rectifier.

Figure 13.6 Six‐pulse rectifier detailed and simplified CM model.

Figure 13.7 CM voltage and current for six‐pulse rectifier as derived from t...

Figure 13.8 CM modeling of a ground fault.

Figure 13.9 CM currents from a three‐phase model.

Figure 13.10 CM currents from the simplified CM model.

Figure 13.11 Asymmetrical circuit.

Figure 13.12 Asymmetrical CM voltage and currents.

Figure 13.13 Symmetrical circuit.

Figure 13.14 Symmetrical CM voltage and currents.

Figure 13.15 DC source with 1 kHz ripple and negative ground schematic.

Figure 13.16 DC source with 1 kHz ripple and negative ground CM current.

Figure 13.17 Split DC source with 1 kHz ripple.

Figure 13.18 Split DC source with 1 kHz ripple CM current.

Figure 13.19 Ring bus schematic.

Figure 13.20 Ring bus CM current.

Figure 13.21 Modeling mutual inductance.

Figure 13.22 CM current with mutual inductance of cable modeled.

Figure 13.23 CM voltage measurements of an inverter: (a) DC side; (b) AC sid...

Figure 13.24 Four‐conductor cable with conductor shield and cable shield....

Figure 13.25 Models of a two‐conductor cable with and without cable shields....

Figure 13.26 CM currents through the ship's hull and cable shield.

Figure 13.27 Balanced inductors.

Figure 13.28 CM choke.

Figure 13.29 Three‐phase CM choke.

Figure 13.30 Capacitor shunts.

Figure 13.31 Inductor‐based shunt.

Figure 13.32 Combination inductor‐based shunt and capacitor.

Figure 13.33 Use of CM choke to control CM currents.

Figure 13.34 Use of CM choke and CM shunt to control CM at interfaces: Optio...

Figure 13.35 Use of CM choke and CM shunt to control CM at interfaces: Optio...

Figure 13.36 Use of CM choke and CM shunt to control CM at interfaces: Optio...

Figure 13.37 Use of CM choke and CM shunt to control CM at interfaces: Optio...

Figure 13.38 CM features of a motor.

Figure 13.39 CM model of a motor.

Chapter 14

Figure 14.1 Bonding cable on superstructure door.

Figure 14.2 Bonding single‐conductor cable for gasketed equipment cover to t...

Figure 14.3 Bonding equipment frame to the foundation.

Figure 14.4 Bonding to a common protective earth bus.

Figure 14.5 Use of a bonding strap to bond the equipment cover to the equipm...

Figure 14.6 MIL‐STD‐1310 Class A bond.

Figure 14.7 MIL‐STD‐1310 Class B bond.

Figure 14.8 MIL‐STD‐1310 (2009) Class C bond for isolated electrical equipme...

Figure 14.9 MIL‐STD‐1310 (2009) Class C bond for bolted electrical equipment...

Figure 14.10 Bonding of electrical equipment box covers.

Figure 14.11 Wire cable bond strap, type I.

Figure 14.12 Metal strip bond strap, type II and type III.

Figure 14.13 Metal braid bond strap, type IV.

Chapter 15

Figure 15.1 Example polarization curve.

Figure 15.2 Corrosion current density for two metals of equal area.

Figure 15.3 Corrosion current density for two metals with the cathode one‐te...

Figure 15.4 Corrosion current density for two metals with the cathode 10 tim...

Figure 15.5 Impact of voltage on metal corrosion.

Figure 15.6 Shaft grounding system.

Figure 15.7 Sacrificial anodes on ship’s rudder.

Figure 15.8 MIL‐DTL‐18001 type ZBS sacrificial anode.

Figure 15.9 Shipboard ICCP system.

Chapter 16

Figure 16.1 Lightning at sea.

Figure 16.2 Representative lightning current waveform.

Figure 16.3 Rolling sphere method.

Figure 16.4 Arrow pointing to air terminal (lightning rod) on frigate mast....

Figure 16.5 Lightning protection system for nonmetallic hull ship.

Chapter 17

Figure 17.1 System grounding and bonding on a nonmetallic hull ship.

Figure 17.2 Protective earthing on a nonmetallic hull ship with an ungrounde...

Appendix C

Figure C.1 Let‐go current for men as a function of frequency.

Guide

Cover Page

Series Page

Title Page

Copyright Page

About the Authors

Preface

Table of Contents

Begin Reading

Appendix A Glossary

Appendix B Acronyms and Abbreviations

Appendix C Impact of Electric Current on Humans

Index

WILEY END USER LICENSE AGREEMENT

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IEEE Press

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Diomidis Spinellis

Design of Shipboard Power System Grounding/Earthing

Norbert Doerry

Mohammed M. Islam

John Prousalidis

Published byStandards Information Network

Copyright © 2025 by The Institute of Electrical and Electronics Engineers, Inc. All rights reserved.

Published by John Wiley & Sons, Inc., Hoboken, New Jersey.Published simultaneously in Canada.

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Library of Congress Cataloging‐in‐Publication DataNames: Doerry, Norbert, author. | Islam, Mohammed M., author. Prousalidis, John, 1968– author.Title: Design of shipboard power system grounding/earthing / Norbert Doerry, Mohammed M. Islam, John Prousalidis.Description: Hoboken, New Jersey : Wiley, [2025] | Includes bibliographical references and index.Identifiers: LCCN 2024034344 (print) | LCCN 2024034345 (ebook) | ISBN 9781119933083 (hardback) | ISBN 9781119933090 (adobe pdf) | ISBN 9781119933106 (epub)Subjects: LCSH: Ships–Electric equipment. | Electric currents–Grounding.Classification: LCC VM471 .I748 2025 (print) | LCC VM471 (ebook) | DDC 623.8/503–dc23/eng/20240819LC record available at https://lccn.loc.gov/2024034344LC ebook record available at https://lccn.loc.gov/2024034345

Cover Design: WileyCover Images: © Norbert Doerry, © nattapon supanawan/Shutterstock

About the Authors

Dr. Norbert Doerry has over 40 years of experience in the operation, design, construction, repair, and modernization of naval ships; he is an internationally recognized expert in shipboard power system design and naval ship design. He is a retired US naval officer having attained the rank of Captain as an engineering duty officer. Dr. Doerry is a graduate of the United States Naval Academy with an electrical engineering bachelor degree and has earned three degrees from MIT: a master of science in electrical engineering and computer science, a naval engineers degree, and a PhD in naval electrical power systems. He is currently focused on ship design activity modeling, developing ship design tools, educating the ship and ship power system design workforce, and developing IEEE standards for shipboard applications. Dr. Doerry chairs standards development working groups for IEEE Std 45.1 and 45.3. He is a fellow in the Society of Naval Architects and Marine Engineers (SNAME) and has been recognized with a number of awards including the American Society of Naval Engineers (ASNE) Gold Medal, the Legion of Merit, and the Superior Civilian Service Award. He is an active member of IEEE, SNAME and ASNE and has published over 100 papers and reports. Dr. Doerry lives in Burke, Virginia, with his wife; he has two children and two grandchildren residing nearby.

Mohammed M. Islam is a retired marine electrical power system design engineer with 50 years of experience. He has participated in shipboard electrical power system standard development for 25 years. As chair of the IEEE Std 45 working group, he initiated many IEEE standards such as IEEE Std 45.1 through IEEE Std 45.8, IEEE Std 1580, IEEE Std 1713, and IEEE Std 1662. IEEE‐1713 has become International standard ISO/IEC/IEEE‐80005 series defining a global standard on ship‐to‐shore interconnections. The 80005 series of standards are paving the path in support of HV, LV, and DC ship‐to‐shore interconnections in support of sustainable port, green shipping, and cold ironing. He currently chairs the working group updating IEEE Std 45.7 on shipboard power system switchboards. Mohammed M. Islam founded the Marine System Coordinating Committee (MSCC) and served as its inaugural chairperson. Born in Pakistan (now Bangladesh), he is a marine engineering graduate of 1966 (fourth batch) from Juldia Marine Academy Pakistan. He earned a bachelor of electrical engineering degree from New York State University, Fort Schuyler Maritime College, in 1974. Mohammed M. Islam's scientific interests include design and development of ship electric propulsion, All Electric Ship, green ships, alternative fuels, cold ironing, smart and sustainable ports, and HVAC/HVDC interconnections. In addition to many technical papers, he has previously authored three books on shipboard electrical power system and coauthored one book. When not performing shipboard power system design and development consultancy work, Mohammed M. Islam enjoys a retired family life with his wife, children, and grandchildren.

Dr. John Prousalidis is a full professor and the director of the Marine Engineering Laboratory of the National Technical University of Athens (NTUA). Born in Athens, Greece, he received his MSc (1991) and PhD (1997) degrees from the School of Electrical and Computer Engineering of NTUA. In 2001, he joined the Academic Staff of the School of Naval Architecture and Marine Engineering of NTUA in the scientific field of “marine electrical and electronic engineering.” He is the author/coauthor of 4 books, about 100 papers, reviewer in IEEE, IET, Elsevier and IMarEST journals. He is a member of the Technical Chamber of Greece, IEEE, IMarEST, member of the board of the Hellenic Joint Branch of RINA/IMarEST, member of the Publication Supervisory Board of IMarEST Publications. He is currently serving as the vice‐chairman of the IEEE Marine Power Systems Coordinating Committee (IEEE‐MSCC), is a member of the IEEE/EPPC Working Group on Energy, is member of the IEC/ISO/IEEE JWG28 dealing with 80005 series of standards on ship‐to‐shore interconnections, and since September 2022 is head of the Industrial Connection Activity Sustainable Maritime of ΙΕΕΕ(ICA‐22‐013). He has participated in about 45 research projects and was the coordinator of 15. His scientific interests include ship electric propulsion, All Electric Ship, green ships, alternative fuels, cold ironing, smart and sustainable ports, and HVDC/HVAC submersible interconnections.

Preface

In the realm of terrestrial and shipboard power systems, the concept of “ground” (or “earth” per IEC) is a term that is often used interchangeably, implying a common understanding. However, the reality of shipboard power system grounding is quite distinct as it pertains to the unique voltage potential associated with the vast ocean. Given that for most ships, the metallic hulls and structures are in direct contact with the ocean, it is accurate to describe these elements as being at “ground” (or “earth”) potential.

Shipboard power systems can be ungrounded, solidly grounded, or resistance grounded; since shipboard power systems may have multiple separately derived systems, ships can have examples of all three grounding methods depending on specific application requirements.

Ungrounded and high‐resistance grounded shipboard power systems possess a remarkable feature: an inadvertent grounding of a single conductor leads to low ground fault currents. This, in turn, facilitates uninterrupted operation in the presence of such a fault. The implementation of high‐resistance grounded systems has witnessed a growing prevalence within distribution networks with nominal system voltages exceeding 1000 V. More recently, this practice has found its way into systems with nominal voltages as low as 440 V. Solidly grounded systems exist where commonality with commercial equipment is desired.

Moreover, shipboard power systems equipped with power electronic conversion devices, such as variable frequency drives (VFDs), demand a rigorous effort to ensure the proper control of harmonic distortion and common‐mode (CM) currents and voltages. The effective management of CM currents and voltages necessitates additional consideration in grounding strategies.

Bonding, often referred to as protective earthing (PE), encompasses the deliberate act of connecting exposed metal components, which are not designed to carry electrical currents during standard operations, to the ship's hull through a low‐impedance pathway. Bonding primarily serves as a safety measure, mitigating the risk of electrical shocks to personnel arising from capacitively coupled voltages on exposed metal parts, inductively coupled currents within those parts, or insulation failures.

One of the coauthors, Mohammed M. Islam, boasts an impressive five decades of experience in designing shipboard power systems and conducting research on these systems, including their grounding aspects. Following the completion of a full electrical propulsion ship with a 6600 V power generation system, he recognized the need to seek clarification on several shipboard power generation, distribution, and grounding issues. This led to contact with the IEEE‐45 working group, which revealed that the work to address these issues was indeed substantial.

Subsequently, Moni took on a leadership role within the IEEE‐45 working group. Over the course of a decade, twelve standards were introduced to support the design and development of shipboard power systems. Additionally, Moni authored three books to elucidate the design and development of shipboard power systems as a complementary resource to the IEEE standards.

During the development of these books, it became apparent that a comprehensive treatise on grounding was warranted, but it would necessitate the collective wisdom of national and international experts. Recognizing the complexity of grounding issues, Moni concluded his existing research was insufficient to address this challenge independently. He reached out to the distinguished Dr. Norbert Doerry, whose qualifications in shipboard grounding were unparalleled. Dr. Doerry has led or been in leadership roles of multiple IEEE standards working groups. He has also published extensively on ship design and ship power system design. Dr. Doerry wholeheartedly grasped the importance of this endeavor and graciously accepted the offer to collaborate. To ensure a well‐rounded perspective, Moni also engaged the IEC expertise of Dr. John Prousalidis from Greece. Dr. Prousalidis significant experience with cold ironing (shore power) and European practices proved invaluable.

The twenty‐month journey to create this book on shipboard grounding was born from the recognition of a critical gap in the field and the collective effort of renowned experts in the domain. The authors met online almost every week during this journey; we learned much during these focused discussions on shipboard grounding. In particular, we discovered the need to clearly distinguish between power system grounding, common‐mode grounding, and protective earthing; this discrimination led to the book focusing chapters on these three types of grounding.

This book is designed to be a valuable resource for academicians and students in the classroom; it offers a wealth of drawings, analytical presentations, data, guidance, models, simulations, and photos. For shipboard power system design engineers, it serves as a comprehensive design guide.

We sincerely hope that this work will contribute significantly to the understanding and practice of shipboard power system grounding and electrical safety will enhance significantly.

1Introduction

1.1 General

Shipboard power distribution systems have existed since the late nineteenth century. Only until recently, both commercial and naval ships have predominantly employed ungrounded power systems with nominal system voltages less than 1 kV. Ungrounded systems, equivalent to isolated systems (IEC), have a desirable feature in that the unintentional grounding of one conductor results in low ground fault currents and thus enables continued operation with a single ground fault. The ship's engineers can wait for a favorable time to find and clear the ground fault. For many years, ungrounded power systems served the maritime industry well.

However, over the past decades, the total electric load on many types of ships has risen, first due to the addition of heat loads that were previously served by steam prior to the adoption of diesel and gas turbine engines, and second due to the introduction of integrated electric propulsion in the form of an integrated power system (IPS) in the 1990s. In response to this growing load, ships started to employ increasingly higher power generation systems with nominal system voltages greater than 1 kV up to 13.8 kV. For these higher voltages, employing an ungrounded system is not recommended due to voltage stresses on system insulation and due to potential safety concerns. Instead, the use of a high‐resistance grounded (HRG) system has become prevalent for distribution systems with nominal system voltages above 1 kV and more recently has been employed in some systems with a nominal system voltage as low as 440 V. The desire to be able to easily integrate commercial equipment designed for shore‐based facilities has even resulted in some solidly grounded secondary distribution systems.

Additionally, power electronic conversion equipment, such as variable frequency drives (VFDs), has become prevalent in shipboard systems; VFDs enable motors and motor loads to operate at higher efficiencies, reduce inrush current, and increase displacement power factor. On the other hand, the integration of VFDs requires significant effort to ensure harmonic distortion and common mode (CM) currents and voltages are properly controlled. Controlling CM currents and voltages requires additional grounding considerations.

1.2 Grounding and Earthing Definitions

In terrestrial systems, the term “ground” (USA) or “earth” (IEC) refers to the voltage potential of the soil at a particular location and is used as a reference potential for measuring the voltage of other conductors. In some terrestrial power systems, the soil itself (at ground voltage potential) may be used as one of the conductors in the power circuit.

In shipboard systems, the term “ground” or “earth” refers to the voltage potential of the ocean. Since most ships have metallic hulls and structure in direct contact with the ocean, the hull and structure are also said to be at “ground” or “earth” potential. However, because of safety and corrosion concerns, the ship's hull and structure are not normally used as one of the conductors in the power circuit.

Bonding is the act of deliberately connecting exposed metal parts that are not designed to carry electrical currents under normal operation to the hull of the ship via a low‐impedance path. Bonding is primarily performed as a safety measure to prevent electrical shock to personnel caused by capacitively coupled voltages on the exposed metal parts, inductively coupled currents in exposed metal parts, or insulation failures. The impacts of electric currents on humans are discussed in Appendix C.

The connection of exposed metal parts to the chassis or frame of a piece of equipment is indicated on circuit diagrams by IEC Symbol 5020 (Figure 1.1f). A terminal, such as one connected to the chassis, that is intended to be connected to ground for the purpose of implementing bonding is called a protective earth (PE) terminal and is represented by IEC Symbol 5019 (Figure 1.1c). This book will additionally use the symbol depicted in Figure 1.1d to represent the connection of the terminal intended for bonding (IEC Symbol 5019) to the ship's hull. This symbol is used to represent a protective earth, and its incorporation into a design is called protective earthing.

Figure 1.1 Ground symbols: (a) IEC Symbol 5017, (b) IEC Symbol 5018, (c) IEC Symbol 5019, (d) Protective earth, (e) CM ground, and (f) IEC Symbol 5020.

The term “equipotential” means that two conductors have equal voltages with respect to a reference voltage. Two conductors that are electrically connected with a low impedance are equipotential. “Equipotential bonding” and “equipotential grounding” are equivalent to “bonding”; the conductors are at the same voltage as the hull of the ship.

Power distribution system grounding (or earthing (IEC)) is the act of deliberately inserting a solid connection or an impedance between a conductor or neutral of a power system and the hull of the ship. Grounding is usually done to limit conductor voltages with respect to the ship's hull, to provide a path for fault current in the case of a ground fault, and to provide a path for CM currents under normal operations. A ground fault is an unintentional electrical connection between a power system conductor and the ship's hull. A ground fault can be a “solid” ground fault with little resistance, or a fault, such as an arc fault, with a higher resistance.

One may also encounter IEC Symbol 5018 (Noiseless earth), depicted as Figure 1.1b; it is intended to represent a special grounding system for a particular application to minimize CM disturbance or noise on a grounding conductor. These special grounding systems are not covered by this book.

This book distinguishes between power distribution system grounding, protective earthing, and CM grounding. For this book, power distribution system grounding addresses ground currents at frequencies less than three times the fundamental frequency, while CM grounding addresses frequencies at or above three times the fundamental frequency. The two types of grounding do interact; this interaction must be accounted for in the design of each. IEC Symbol 5017 (Figure 1.1a) is used to indicate power system grounding. This book additionally uses the symbol depicted in Figure 1.1e to denote an intentional CM ground. Parasitic connections to ground participate in protective earthing (bonding), power system grounding circuits, and CM circuits; by convention, parasitic component connections to ground are displayed as IEC Symbol 5017. In summary, of the six ground symbols depicted in Figure 1.1, this book will use only the three depicted in Figure 1.2.

Figure 1.2 Ground symbols used in this book: (a) system ground, (b) protective earth, and (c) common mode ground.

Figure 1.3 Use of ground symbols.

Figure 1.3 depicts the use of the three different ground symbols in the case of a single‐phase transformer. The protective earth grounding (left) connects the exposed metallic structure and components of the transformer enclosure (not intended to carry current under normal operation) to ground through bonding. The CM ground (middle) is used to connect the transformer shield between the primary and secondary windings to ground; this shield is used to prevent capacitive coupling of CM currents between the primary and secondary windings. Finally, one of the conductors of the secondary winding is grounded (right) to form a system ground for a solidly grounded distribution system.

Electric current from the power system that, under normal conditions, flows through conductors that are not intended to carry power system current, such as conductors associated with protective earthing, is called objectionable current. Objectionable currents may arise when inappropriate connections are made between the power system and protective earthing conductors.

As defined by IEEE Std 45.1‐2023 (2023), the nominal system voltage is “the designated voltage for a power system used as a reference value for establishing other power quality measures. For direct current, single‐phase AC, and three‐phase AC systems, the nominal system voltage is measured line‐to‐line.” For AC systems, the nominal system voltage is expressed as a root‐mean‐square (rms) of the fundamental frequency component of the voltage waveform.

1.3 Common Mode Terminology

The neutral voltage of a set of conductors with respect to a reference voltage potential (typically ground) at any instant in time is the average value of the instantaneous conductor voltages with respect to the reference voltage. The neutral voltage is also called a CM voltage. Strictly speaking, the neutral voltage is a calculated quantity from the voltage measurements of multiple conductors and may not correspond to the voltage of any one conductor.

For a three‐phase system, the neutral voltage with respect to ground can be expressed as

(1.1)

(1.2)

where

vng, neutral‐to‐ground voltage

vag, vbg, vcg, phase‐to‐ground voltage

van, vbn, vcn, phase‐to‐neutral voltage

Through substitution

The sum of the phase voltages with respect to the neutral is identically zero.

The instantaneous sum of the conductor currents in a set of conductors is called the CM current. In a balanced system, the CM current of a set of conductors is equal to zero; the sum of the currents in one direction is equal to the sum of the currents in the opposite direction. CM currents often, but not always, have a return path to a CM source via ground connections.

CM current is unintended; the intended differential mode (DM) currents of a set of conductors add to zero when measured in the same direction.

Power electronics, such as VFDs, and circuit asymmetry can be significant CM voltage sources in shipboard power systems. CM circuits include line impedances, parasitic capacitances to ground, and CM grounding systems. In some cases, inductive coupling with bonded conductors can also lead to CM voltages and currents.

A neutral conductor is intended to have a voltage potential equal to the neutral voltage of a set of conductors. However, due to voltage distortion of the phase voltages, the voltage potential of the neutral conductor may vary somewhat from the neutral voltage of an associated set of conductors.

1.4 Types of Power Distribution Systems

IEEE 45.1‐2023 identifies the following types of buses to categorize shipboard power systems:

Primary bus: distribution systems with a nominal system voltage greater than 1 kV.

Distribution bus: distribution systems with a nominal system voltage between 400 V and 1 kV.

Secondary bus: distribution systems with a nominal system voltage no greater than 400 V.

Special bus: circuits for unique purposes such as medical use, control system power, or special control.

This book adapts the IEEE 45.1‐2023 terminology to refer to power distribution systems:

Primary distribution system: a power distribution system with an IEEE Std 45.1‐2023 primary bus.

Low‐voltage distribution system: a power distribution system with an IEEE 45.1‐2023 distribution bus.

Low‐voltage secondary distribution system: a power distribution system with an IEEE 45.1‐2023 secondary bus.