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Arc Flash Hazards Analysis ARC FLASH HAZARDS ANALYSIS by ZHENYUAN ZHANG Presented to the Faculty of the Graduate School of The University of Texas at Arlington in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY THE UNIVERSITY OF TEXAS AT ARLINGTON December 2015 Copyright © by Zhenyuan Zhang 2015 All Rights Reserved ii Acknowledgements I would like to express deep gratitude to my supervising professor, Dr. Wei-Jen Lee for his guidance, encouragement, patience, and support throughout my entire doctoral program at the University of Texas at Arlington. He encouraged me to not only grow as an electrical engineer but also grow as independent and creative thinker. Also, I would like to take this opportunity to convey my sincere gratitude to Dr. Lee for extending his support and guidance leading me to complete this dissertation. I am blessed to have adviser like him. I would like to thank my doctoral dissertation committee members: Dr. William E. Dillon, Dr. Rasool Kenarangui, Dr. David A. Wetz, and Dr. Ali Davoudi. Thanks for their valuable and detailed instruction, suggestions and review. I would also like to thank for the members of the Energy Systems Research Center. Thank for all of their helps and the friendship in last six and half years. They are not only the team members in my researches but also bring me laugh, happiness, and inspirations during the stressful graduate life. Also, I want to express my great thanks to Mr. Lydon Lee, who helps me a lot on the dissertation revision. I wish to thank for all the Steering Committee and Technical Advisory Committee members of IEEE/NFPA collaboration on arc flash phenomena research project. Thank for their support and valuable suggestions and guidance throughout the project. It is my great honor to be a part of the team. Finally, I would dedicate my dissertation to my parents. Their support, encouragement, patience and unwavering love were serving as my continued source of inspiration for the tenure of my doctoral degree. Without them, this work would never have been accomplished. November 20, 2015 iii Abstract ARC FLASH HAZARDS ANALYSIS Zhenyuan Zhang, PhD The University of Texas at Arlington, 2015 Supervising Professor: Wei-Jen Lee Annually more than 2000 workers are admitted to hospital burn centers for extensive injuries caused by arc flash accidents. Arc flash incidents occur when unintended electric current flows through air, superheating the air and causes an explosion. Recognizing the significant threat posed by arc flash hazards, IEEE and NFPA have joined forces on an initiative to support research and additional testing to increase the understanding of the arc flash phenomena. Accurately represent all the real applications for arc flash events are very difficult, not only because of their random complex nature, but also because a large number of uncertain variables involved. Several areas of the arc flash phenomena need further research and testing validation. In order to have a precise arc flash hazards assessment, approximately 2000 arc flash experiments had been conducted, which are crossed extensive range of system voltage, bolted fault current, electrodes gap width, arc initiative configuration and enclosure dimensions. This dissertation has reviewed the testing methodology, test equipment design and modeling process for arc flash hazards analysis. The research and testing focused on, but will not be limited to (a) the development of physics and engineering-based modeling for arc flash thermal hazards, and (b) design and testing for non-thermal hazards, such as light, pressure and sound. iv Based on the works of the dissertation, sets of assessment equations and approaches have been proposed for arc flash thermal and non-thermal hazard analysis. The results of this dissertation will provide information to help more accurately predict the hazards associated with high energy arcing faults, thereby improving electrical safety standards and providing practical safeguards for employees in the work place. v Table of Contents Acknowledgements .............................................................................................................iii Abstract .............................................................................................................................. iv List of Illustrations ............................................................................................................... x List of Tables .....................................................................................................................xvi Chapter 1 Introduction......................................................................................................... 1 1.1 Introduction of arc flash phenomenon ...................................................................... 1 1.2 Overview of arc flash hazards .................................................................................. 1 1.3 Research motivation ................................................................................................. 5 1.4 Research objective ................................................................................................... 7 1.5 Dissertation overview ............................................................................................... 8 Chapter 2 Review on arc flash researches ....................................................................... 10 2.1 Nature of arcing phenomena .................................................................................. 10 2.2 Arc initiation ............................................................................................................ 12 2.3 Arc regions and arc column .................................................................................... 13 2.4 Incident energy and heat transfer ........................................................................... 15 2.4.1 Incident energy ................................................................................................ 15 2.4.2 Personal protective equipment ........................................................................ 16 2.4.3 Heat transfer .................................................................................................... 17 2.5 Review on previous arc flash hazards analysis researches ................................... 19 2.5.1 Stoll curve ........................................................................................................ 19 2.5.2 Ralph Lee’s equations ..................................................................................... 20 2.5.3 Arc flash testing and modeling in mid-1990s .................................................. 21 2.5.4 IEEE Std. 1584-2002 “Guide for Performing Arc Flash Calculations” ............................................................................................................. 22 vi 2.5.5 Researches after IEEE 1584 -2002................................................................. 23 Chapter 3 Design and perform arc flash testing for model development ......................... 25 3.1 Definitions of testing parameters ............................................................................ 25 3.2 Overview of test set up ........................................................................................... 28 3.3 Testing methodology and ranges ........................................................................... 35 3.4 Testing summary .................................................................................................... 37 3.5 Design of testing equipment ................................................................................... 40 3.5.1 Data acquisition system .................................................................................. 40 3.5.2 Issues of DAQ system isolation and grounding .............................................. 43 3.5.3 Improved design for arc flash measurement system ...................................... 45 3.5.4 Design of power supply for measurement equipment ..................................... 50 3.5.5 Design of signal transferring ............................................................................ 52 3.5.6 Arc flash measurement system integration ..................................................... 53 3.6 Sample Test Results .............................................................................................. 55 Chapter 4 Model development for arcing current and incident energy ............................. 56 4.1 Testing data processing ......................................................................................... 56 4.1.1 Arcing current data processing ........................................................................ 56 4.1.2 Incident energy data processing ..................................................................... 62 4.2 Modeling parameters sensitivity analysis ............................................................... 64 4.2.1 Arcing current parameter sensitivity analysis .................................................. 72 4.2.2 Incident energy parameter sensitivity analysis ................................................ 75 4.3 Arcing current and Incident energy modeling procedure ....................................... 78 4.4 Model Implementation ............................................................................................ 83 4.5 Model validation and example ................................................................................ 88 4.5.1 Arcing
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