J. C. Das - Arc Flash Hazard Analysis and Mitigation

1 COVER

2 TITLE PAGE ARC FLASH HAZARD ANALYSIS AND MITIGATION Second Edition J.C. Das

3 COPYRIGHT PAGE Copyright © 2021 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. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 750-4470, or on the web at www.copyright.com . Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, or online at http://www.wiley.com/go/permissions . Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. For general information on our other products and services or for technical support, please contact our Customer Care Department within the United States at (800) 762-2974, outside the United States at (317) 572-3993 or fax (317) 572-4002. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic formats. For more information about Wiley products, visit our web site at www.wiley.com . Library of Congress Cataloging-in-Publication data applied for ISBN 978-1-118-16381-8 Cover Design: Wiley Cover Images: (Top image) © Sam Robinson/Getty Images, (Center image) © Chanin Wardkhian, © Ashwini H/Getty Images Design

4 FOREWORD

5 PREFACE TO SECOND EDITION

6 PREFACE TO FIRST EDITION

7 ACKNOWLEDGEMENT

8 ABOUT THE AUTHOR

9 1 ARC FLASH HAZARDS AND THEIR ANALYSES 1.1 ELECTRICAL ARCS 1.2 ARC FLASH HAZARD AND PERSONAL SAFETY 1.3 TIME MOTION STUDIES 1.4 ARC FLASH HAZARDS 1.5 ARC BLAST 1.6 ELECTRICAL SHOCK HAZARD 1.7 FIRE HAZARD 1.8 ARC FLASH HAZARD ANALYSIS 1.9 PERSONAL PROTECTIVE EQUIPMENT 1.10 HAZARD BOUNDARIES 1.11 MAXIMUM DURATION OF AN ARC FLASH EVENT AND ARC FLASH BOUNDARY 1.12 REASONS FOR INTERNAL ARCING FAULTS 1.13 ARC FLASH HAZARD CALCULATION STEPS 1.14 EXAMPLES OF CALCULATIONS 1.15 REDUCING ARC FLASH HAZARD REVIEW QUESTIONS REFERENCES

10 2 SAFETY AND PREVENTION THROUGH DESIGN: A NEW FRONTIER 2.1 ELECTRICAL STANDARDS AND CODES 2.2 PREVENTION THROUGH DESIGN 2.3 LIMITATIONS OF EXISTING CODES, REGULATIONS, AND STANDARDS 2.4 ELECTRICAL HAZARDS 2.5 CHANGING THE SAFETY CULTURE 2.6 RISK ANALYSIS FOR CRITICAL OPERATION POWER SYSTEMS 2.7 RELIABILITY ANALYSIS 2.8 MAINTENANCE AND OPERATION 2.9 SAFETY INTEGRITY LEVEL AND SAFETY INSTRUMENTED SYSTEM 2.10 ELECTRICAL SAFETY IN THE WORKPLACES 2.11 RISK REDUCTION 2.12 RISK EVALUATION 2.13 RISK REDUCTION VERIFICATION 2.14 RISK CONTROL REVIEW QUESTIONS REFERENCES

11 3 CALCULATIONS ACCORDING TO IEEE GUIDE 1584, 2018 3.1 MODEL FOR INCIDENT ENERGY CALCULATIONS 3.2 ELECTRODE CONFIGURATION 3.3 IMPACT OF SYSTEM GROUNDING 3.4 INTERMEDIATE AVERAGE ARCING CURRENT 3.5 ARCING CURRENT VARIATION FACTOR 3.6 CALCULATION OF INTERMEDIATE INCIDENT ENERGY 3.7 INTERMEDIATE ARC FLASH BOUNDARY (AFB) 3.8 ENCLOSURE SIZE CORRECTION FACTOR 3.9 DETERMINE EQUIVALENT HEIGHT AND WIDTH 3.10 DETERMINE ENCLOSURE SIZE CORRECTION FACTOR 3.11 DETERMINATION OF I ARC, E , AND AFB (600 V < V OC≤ 15,000 V) 3.12 DETERMINATION OF I ARC, E , AND AFB ( V OC≤ 600 V) 3.13 A FLOW CHART FOR THE CALCULATIONS 3.14 EXAMPLES OF CALCULATIONS REFERENCES

12 4 ARC FLASH HAZARD AND SYSTEM GROUNDING 4.1 SYSTEM AND EQUIPMENT GROUNDING 4.2 LOW RESISTANCE GROUNDING 4.3 HIGH RESISTANCE GROUNDED SYSTEMS 4.4 UNGROUNDED SYSTEMS 4.5 REACTANCE GROUNDING 4.6 RESONANT GROUNDING 4.7 CORNER OF DELTA-GROUNDED SYSTEMS 4.8 SURGE ARRESTERS 4.9 ARTIFICIALLY DERIVED NEUTRALS 4.10 MULTIPLE GROUNDED SYSTEMS 4.11 ARC FLASH HAZARD IN SOLIDLY GROUNDED SYSTEMS 4.12 PROTECTION AND COORDINATION IN SOLIDLY GROUNDED SYSTEMS 4.13 GROUND FAULT COORDINATION IN LOW RESISTANCE GROUNDED MEDIUM VOLTAGE SYSTEMS 4.14 MONITORING OF GROUNDING RESISTORS 4.15 SELECTION OF GROUNDING SYSTEMS REVIEW QUESTIONS REFERENCES

13 5 SHORT-CIRCUIT CALCULATIONS ACCORDING TO ANSI/IEEE STANDARDS FOR ARC FLASH ANALYSIS 5.1 TYPES OF CALCULATIONS 5.2 RATING STRUCTURE OF HV CIRCUIT BREAKERS 5.3 LOW-VOLTAGE MOTORS 5.4 ROTATING MACHINE MODEL 5.5 CALCULATION METHODS 5.6 NETWORK REDUCTION 5.7 CALCULATION PROCEDURE 5.8 CAPACITOR AND STATIC CONVERTER CONTRIBUTIONS TO SHORT-CIRCUIT CURRENTS 5.9 TYPICAL COMPUTER-BASED CALCULATION RESULTS 5.10 EXAMPLES OF CALCULATIONS 5.11 THIRTY-CYCLE SHORT-CIRCUIT CURRENTS 5.12 UNSYMMETRICAL SHORT-CIRCUIT CURRENTS 5.13 COMPUTER METHODS 5.14 SHORT-CIRCUIT CURRENTS FOR ARC FLASH CALCULATIONS REVIEW QUESTIONS REFERENCES

14 6 ACCOUNTING FOR DECAYING SHORT-CIRCUIT CURRENTS IN ARC FLASH CALCULATIONS 6.1 SHORT CIRCUIT OF A PASSIVE ELEMENT 6.2 SYSTEMS WITH NO AC DECAY 6.3 REACTANCES OF A SYNCHRONOUS MACHINE 6.4 SATURATION OF REACTANCES 6.5 TIME CONSTANTS OF SYNCHRONOUS MACHINES 6.6 SYNCHRONOUS MACHINE BEHAVIOR ON TERMINAL SHORT CIRCUIT 6.7 SHORT CIRCUIT OF SYNCHRONOUS MOTORS AND CONDENSERS 6.8 SHORT CIRCUIT OF INDUCTION MOTORS 6.9 A NEW ALGORITHM FOR ARC FLASH CALCULATIONS WITH DECAYING SHORT-CIRCUIT CURRENTS 6.10 CROWBAR METHODS REVIEW QUESTIONS REFERENCES

15 7 PROTECTIVE RELAYING 7.1 PROTECTION AND COORDINATION FROM ARC FLASH CONSIDERATIONS 7.2 CLASSIFICATION OF RELAY TYPES 7.3 DESIGN CRITERIA OF PROTECTIVE SYSTEMS 7.4 OVERCURRENT PROTECTION 7.5 LOW VOLTAGE CIRCUIT BREAKERS 7.6 SHORT-CIRCUIT RATINGS OF LOW VOLTAGE CIRCUIT BREAKERS 7.7 SERIES-CONNECTED RATINGS 7.8 FUSES 7.9 APPLICATION OF FUSES FOR ARC FLASH REDUCTION 7.10 CONDUCTOR PROTECTION 7.11 MOTOR PROTECTION 7.12 GENERATOR 51-V PROTECTION REVIEW QUESTIONS REFERENCES

16 8 UNIT PROTECTION SYSTEMS 8.1 OVERLAPPING THE ZONES OF PROTECTION 8.2 IMPORTANCE OF DIFFERENTIAL SYSTEMS FOR ARC FLASH REDUCTION 8.3 BUS DIFFERENTIAL SCHEMES 8.4 HIGH IMPEDANCE DIFFERENTIAL RELAYS 8.5 LOW IMPEDANCE CURRENT DIFFERENTIAL RELAYS 8.6 ELECTROMECHANICAL TRANSFORMER DIFFERENTIAL RELAYS 8.7 MICROPROCESSOR-BASED TRANSFORMER DIFFERENTIAL RELAYS 8.8 PILOT WIRE PROTECTION 8.9 MODERN LINE CURRENT DIFFERENTIAL PROTECTION 8.10 EXAMPLES OF ARC FLASH REDUCTION WITH DIFFERENTIAL RELAYS REVIEW QUESTIONS REFERENCES

17 9 ARC FAULT DETECTION RELAYS 9.1 PRINCIPLE OF OPERATION 9.2 LIGHT INTENSITY 9.3 LIGHT SENSOR TYPES 9.4 OTHER HARDWARE 9.5 SELECTIVE TRIPPING 9.6 SUPERVISION WITH CURRENT ELEMENTS 9.7 APPLICATIONS 9.8 EXAMPLES OF CALCULATION 9.9 ARC VAULT™ PROTECTION FOR LOW VOLTAGE SYSTEMS REVIEW QUESTIONS REFERENCES

18 10 OVERCURRENT COORDINATION 10.1 STANDARDS AND REQUIREMENTS 10.2 DATA FOR THE COORDINATION STUDY 10.3 COMPUTER-BASED COORDINATION 10.4 INITIAL ANALYSIS 10.5 COORDINATING TIME INTERVAL 10.6 FUNDAMENTAL CONSIDERATIONS FOR COORDINATION 10.7 COORDINATION ON INSTANTANEOUS BASIS 10.8 NEC REQUIREMENTS OF SELECTIVITY 10.9 THE ART OF COMPROMISE REVIEW QUESTIONS REFERENCES