Rodolfo Araneo - Electrical Safety Engineering of Renewable Energy Systems

Rodolfo Araneo

University of RomeRome, Italy

Massimo Mitolo

Irvine Valley College Irvine, California

This edition first published 2022

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Library of Congress Cataloging-in-Publication Data

Names: Araneo, Rodolfo, author. | Mitolo, Massimo A. G., author. | John

Wiley & Sons, publisher.

Title: Electrical safety engineering of renewable energy systems / Rodolfo

Araneo, Massimo Mitolo.

Description: Hoboken : John Wiley & Sons, 2022. | Includes bibliographical

references and index.

Identifiers: LCCN 2021025391 (print) | LCCN 2021025392 (ebook) | ISBN

9781119624981 (hardback) | ISBN 9781119624998 (pdf) | ISBN 9781119625018 (epub)

| ISBN 9781119625056 (ebook)

Subjects: LCSH: Electric apparatus and appliances--Safety measures. |

Renewable energy sources--Safety measures.

Classification: LCC TK152 .A73 2022 (print) | LCC TK152 (ebook) |

DDC 621.3028/9--dc23

LC record available at https://lccn.loc.gov/2021025391

LC ebook record available at https://lccn.loc.gov/2021025392

Cover image: © oxygen/Getty

Cover design by Wiley

Set in 9.5/12.5pt STIXTwoText by Integra Software Services, Pondicherry, India.

1 Cover

2 Title page Electrical Safety Engineering of Renewable Energy Systems Rodolfo Araneo University of RomeRome, Italy Massimo Mitolo Irvine Valley College Irvine, California

3 Copyright

4 Preface

5 Acknowledgments

6 1 Fundamental Concepts of Electrical Safety Engineering 1.1 Introduction1.2 Electric Shock1.2.1 Ventricular Fibrillation1.2.2 The Heart-current Factor1.3 The Electrical Impedance of the Human Body1.3.1 The Internal Resistance of the Human Body1.4 Thermal Shock1.5 Heated Surfaces of Electrical Equipment and Contact Burn Injuries1.6 Ground-Potential and Ground-Resistance1.6.1 Area of Influence of a Ground-electrode1.7 Hemispherical Electrodes in Parallel1.8 Hemispherical Electrodes in Series1.9 Person’s Body Resistance-to-ground and Touch Voltages1.10 Identification of Extraneous-Conductive-Parts1.11 Measuring Touch Voltages

7 2 Safety-by-Design Approach in AC/DC Systems 2.1 Introduction2.2 Class I PV Equipment2.3 Class II PV Equipment2.4 Ground Faults and Ground Fault Protection2.5 Functionally Grounded PV Systems2.6 Non-Ground-Referenced PV Systems2.7 Ground-Referenced PV Systems2.8 Fire Hazard in Ground-Referenced PV Systems2.9 Faults at Loads Downstream the PV Inverter in Ground-Referenced PV Systems2.10 Non-Electrically Separated PV System2.11 PV Systems Wiring Methods and Safety2.12 d.c. Currents and Safety2.13 Electrical Safety of PV Systems2.14 Rapid-Shutdown of PV Arrays on Buildings2.15 Hazard and Risk

8 3 Grounding and Bonding 3.1 Introduction3.2 Basic Concepts of Grounding Systems: The Ground Rod3.3 The Maxwell Method3.4 Multiple Rods: Mutual Resistance3.5 Ground Rings and Ground Grid3.6 Complex Arrangements: Rings and Ground Grids Combined with Rods and Horizontal Electrodes

9 4 Lightning Protection Systems4.1 Review of Natural Lightning Physics, Modeling and Protection4.2 Lightning Protection of PV Systems4.2.1 Ground-Mounted PV Systems4.2.2 Rooftop Mounted PV Systems4.2.3 Protection against Overvoltage4.2.4 Surge Protective Devices (SPDs)4.3 Lighting Protection of Wind Turbines4.3.1 Lightning Protection System (LPS)4.3.2 Step and Touch Voltages4.3.3 Lightning Exposure Assessment4.3.4 Assessment of the Average Annual Number of Dangerous Events N LDue to Flashes Directly to and near Service Cables4.3.5 Lightning Protection Zones4.4 High-Frequency Grounding Systems 4.4.1 Arrangement of Ground Electrodes4.4.2 Effective Length of a Ground Electrode4.4.3 Frequency-dependent Soil and Ionization

10 5 Renewable Energy System Protection and Coordination 5.1 Introduction5.2 Power Collection Systems5.3 Cable Connections5.4 Offshore Wind Farm5.5 Distributed Energy Resources: Battery Energy Storage Systems and Electric Vehicles

11 6 Soil Resistivity Measurements and Ground Resistance 6.1 Soil Resistivity Measurements6.2 Wenner Method6.3 Schlumberger Method6.4 Multi-layer Soils6.4.1 Ground Grid in Multi-layer Soil6.4.2 Ground Rod in Multi-layer Soil6.5 Fall-of-Potential Method for Ground Resistance Measurement6.6 Slope Method for Grounding Resistance Measurement6.7 Star-delta Method for Grounding Resistance Measurement6.8 Four Potential Method for Grounding Resistance Measurement6.9 Potentiometer Method for Grounding Resistance Measurement

12 Appendix 1: Performance of Grounding Systems in Transient Conditions 1 Grounding System Analysis2 Mathematical Model3 Computation of Impedances4 Green’s Function4.1 Static Formulation4.1.1 One-Layer Ground4.1.2 Two-Layer Ground4.2 Dynamic Formulation4.2.1 Equivalent Transmission Line Approach5 Numerical Integration Aspects5.1 Singular Term5.2 Sommerfeld Integrals

13 Appendix 2: Cable Failures in Renewable Energy Systems 1 Cable Failures in Renewable Energy Systems: Introduction2 Possible Solutions2.1 Optimal Solutions2.2 Termite Attacks Prevention3 Non-destructive Methods for Cable Testing and Fault-locating3.1 Insulation Resistance (IR) Test3.1.1 IR Measurement of the Cable Insulation (XLPE)3.1.2 IR Measurement of the Polyethylene (PE) Cable Jacket3.2 High-Potential Test3.3 LCR Test3.3.1 Insulation Resistance (IR)3.3.2 Dielectric Absorption Ratio (DAR)3.3.3 Polarization Index (PI)3.3.4 Quality Factor (Q)3.3.5 Dissipation Factor (DF)3.3.6 Time Domain Reflectometry (TDR) Test3.3.7 Arc Reflection (ARC) Test3.3.8 Bridge Methods3.4 Cable Fault Analysis3.4.1 Prelocation3.4.2 Pinpointing4 Sheath and Jacket Repairs5 Termite Baiting Stations and Monitoring6 Termite-proof Cables