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Short Course on Electrical Safety for Utilities |
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Mohamed A El-Sharkawi Department of Electrical Engineering University of Washington Seattle, WA 98195 |
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Course Description |
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Electric utilities place high priorities on providing their workers a safe environment for power line construction and maintenance. In addition, regulatory agencies such as the Occupational Safety and Health Administrations (OSHA) and the Institute of Electrical and Electronics Engineers (IEEE) provide fundamental rules to create a safe working environment for transmission line workers. These rules are published in OSHA standards and the National Electrical Safety Code (NESC). This course covers the foundations of personnel safety for utility work, including: · Transmission line maintenance and construction, including energized and de-energized lines · Ground installations within the right-of-way of transmission lines; such as buildings, parking lots, and roadways · Stray voltage · Atmospheric discharges Applicable OSHA standards, IEEE standards, and the NESC are discussed in conjunction with each topic. The course provides the engineering justifications (modeling and analysis) of the standards and safety codes. Several real-world cases are presented, studied, and analyzed in this course. In addition, some of the tools used to analyze the worksite hazards and to test the safety procedures are discussed. Participants will understand the foundations of electric safety. They will be able to identify hazards at the worksite, and will be able to design effective safety procedures at worksites. Who should attend? Utility engineers Supervisors and workers of power line maintenance Construction and maintenance personnel in companies specialized in power lines Personnel in manufacturing companies of electric safety equipment Attorneys involved in electric safety issues Topics Covers Introduction to Electric Safety Fundamentals Alternating currents Three-phase systems Power line conductors Power line towers Electromagnetic Coupling Electromagnetic field Induced voltage due to electrical field Induced voltage due to magnetic field Computation of induced voltage Case studies Human tolerance to Electricity Biological effects of electricity Safe limits of currents and voltages Resistance of the human body Grounds and grounding systems Definition of grounds Ground resistance of objects Measuring the ground resistance of objects Ground resistance of people Hazards of Electricity Step potential Touch potential Worksite Hazards Identifying hazards Isolation, insulation and grounding techniques Concept of equipotential zone Regulations and standards De-energized line work De-energizing the power line Hazards of de-energized lines Grounding Definition of effective grounds Main equipment used as temporary grounds System grounding Local grounding Traveler ground Creation of the equipotential zone Protection of all workers at the worksite (on tower, inside the boom, and on the ground) Real world case studies Safety dilemma Key standards Live-line work Hazards Basic safety concepts Live-line tools Minimum approach distance Exceptions for bare hand work Aerial work Case studies Key standards and practices Electric field under Power Lines Hazards of induced voltage Electric field strength Industry rules on electric field strength Minimum clearance rules Case studies Atmospheric Discharges Characteristics of lightning Traveling of lightning along power lines Protection of system against lightning Protection of personnel and equipment Stray Voltage Neutral versus ground Grounding practice Sources of stray voltage Elimination of stray voltage |
