Program Abstracts for ESW 2021
Protecting Workers from Electromagnetic Induction During Line-Stringing Operations
David Wallis, Brian Erga
Electromagnetic induction from parallel lines during line-stringing operations poses a serious electrical hazard, which is a leading cause of death for power line workers. This presentation examines the extent of the hazard, its causes, and measures to protect workers. The presentation uses an actual accident to illustrate the hazards and protective measures that could have been used to prevent it.
Working Together, Six Feet Apart
Anthony (Tony) Demaria, Jr., Katie Scarlett Reyes, Joe Barrios
In this paper, we will discuss the struggles of operating a business and keeping employees as safe as possible during the 2020 Covid-19 Pandemic. We linked with other professionals and centers of excellence from around the world in the electrical sector to advance our mission of a Safety-First culture. The innovations required involved human performance best practices to overcome these substantial barriers to everyday work tasks. Our industry needed to adapt, in real-time, to the environments they were in. Engineers, technicians, and electricians dealt daily with this new hazard that they could not see, interestingly not unlike electricity.
To Ground or Not to Ground
This Case Study will cover the timeline of events, highlight improper versus proper job behaviors when working around high voltage, and highlight the need for training and qualification in electrical utility work. The switchgear had been recently installed, and just prior to bringing it fully online, personnel found the phases to be incorrect on the switch. To correct this error, a contractor electrician turned off the switch, applied his lock and tag, and swapped the phases wearing voltage-rated gloves and under-rated arc flash PPE. Subsequent investigation found that the contractors involved were not properly versed in the concepts of creating a safe work condition for medium voltage electrical work as delineated in both 1926 Subpart V and 1910 Subpart R of OSHA, along with other requirements of the National Electrical Safety Code® (NESC®).
Methods for Evaluating DC Arc Incident Energy in PV Systems
William Sekulic, Albert Marroquin, Peter McNutt
Solar Photovoltaic (PV) systems have permeated the energy generation world at a very high rate, safety codes and standards are still lagging in accurately assessing the hazards and risks associated with PV array arcing energies. Safety professionals and maintenance workers using NFPA 70E have utilized the Maximum Power model to calculate incident energy, but experimental data has shown severe discrepancies between these results and real fault data. This paper will present incident energy data, using experimental setups to include various electrode configurations, direct current (DC) power levels less than 30kW and voltages less than 1000 VDC. The paper’s authors intend to help fill in data points on smaller PV systems and improve the overall understanding of how these systems behave under fault conditions. Modelling of data will be limited to the NFPA Maximum Power method, for comparison, and a proposed method to extrapolate data from the PV module IV curves.
Working Around Electricity: Actions Leading to Electrical Fatalities
Brett Brenner, Daniel Majano
According to the U.S. Bureau of Labor Statistics, since the introduction of the Occupational Injury and Illness Classification System 2.01 in 2011, half of all private industry workplace electrical fatalities occurred within the construction industry. Between 2011 and 2019, the Occupational Safety and Health Administration (OSHA) recorded that 378 cases of electrical fatalities occurred during construction projects. OSHA reports show that the greatest number of electrically related fatalities occurred in alterations or rehabilitations and in new projects or addition builds. Many of these construction projects were for single-family, duplex, or commercial building projects. In examining incidents where contacted voltage was recorded, 57% of fatalities occurred when a worker contacted an energy source of over 1,000 volts. Contact with energy sources of 480 volts and 7,200 volts accounted for the greatest number of fatalities. Gaining a better understanding of the jobs being completed and the source of energy contacted can help identify the behaviors and actions that need to be addressed to lower the number of electrical fatalities in the workplace.
Good Things Can Come From Bad Events
Good things can come from bad events. It doesn’t lessen the pain or consequence but can prove to be a coping mechanism to continue on into a happy and fulfilling life. Such is the story of Craig Kroon Van Diest. A young 19-year-old helping a neighbor install a CB antenna on his home in 1975. In the process of placing the 60’ ground plane antenna on the top of a 40’ triangular tower he came into contact with a newly installed 115 kV line along the boundary of their back yard. His misunderstanding of the hazard and the lack of warnings from the local utility added up to change his life forever. Quietly taking solace in the fact that his incident resulted in simple changes made in the utility industry that have since saved countless lives from a similar fate, he struggled in the most engaging and friendly way the rest of his life gladly sharing his lessons learned. Good things can come from bad events but this is no reason to wait for an event to occur before making needed changes. Examining the lessons learned from this one event in 1975 and an honest look at what misunderstood hazards may exist in many facilities today can assist companies and utilities alike in making positive changes before unfortunate events can occur.
Troubleshooting: The “Acceptable” Energized Work
Karl M Cunningham, Michael Kovacic
Troubleshooting, testing, and tuning are words synonymous with energized work due to infeasibility (NFPA 70E 130.2(A)(2)). As such, the hazards associated with troubleshooting are often assumed to be a fact of life one must accept. These hazards are even often overlooked while performing such work. Energized troubleshooting presents significant added challenges to safe work, as it represents the knowledge-based mode, often with error precursors built in when the non-working equipment is holding up production. This paper examines the troubleshooting subject with suggestions on safer troubleshooting work methods for existing installations along with design considerations that follow the hierarchy of controls to reduce the hazards for new and modified installations.
What Happens when the Host Employer Makes a Mistake?
Electrical contractors working for host employers often rely on the host employer to shutdown and lock-out/tag-out (LO/TO) electrical equipment and verify the absence of voltage, to create the electrically safe work condition. The host employer would be performing preventative maintenance (PM) on two substations that provide power to a large portion of the facility, requiring a shutdown of production. Meetings had been held with two contractors earlier in the week, contractor A would be working in a motor control center (MCC) and contractor B performing preventative maintenance and substation breaker calibrations on substations SUB-1A & SUB-1B. The shutdown and LO/TO of each breaker would be performed by the host employer’s electrician. Contractor A would be working in MCC-1A. Contractor B’s work would begin, before contractor A arrived on-site. The day of the shutdown, contractor A’s crew reviewed the host employer’s shutdown paperwork, signed the paperwork, placed their individual locks on the MCC-1A Lock Box, witnessed the absence of voltage test and completed the work in MCC-1A. Work completed, contractor A’s crew and the site electrical lead were walking towards SUB-1A, preparing to unlock the MCC-1A Lock Box. Why did the site electrical lead notice equipment fed from MCC-1A was beginning to power up? What else was wrong or could have gone wrong?
A Balanced Scorecard of Leading and Lagging Indicators for Your Electrical Safety Program
H. Landis “Lanny” Floyd II
Lost time electrical injuries are among the rarest injuries in the workplace, contributing less than 0.2% of all workplace injuries. Yet, contact with electrical energy is a leading cause of fatal injuries. These two attributes, very low frequency and very severe consequence, create a serious challenge in measuring the effectiveness of electrical safety programs. The traditional measurement of injury rates, a lagging indicator, may blind an organization to future injury potential. The low frequency of electrical injuries may result in an organization having insufficient data points to be statistically valid. This paper explores opportunities to complement traditional methods of measuring safety performance with leading indicators to provide a balanced scorecard of lagging and leading indicators to drive continual improvement in reducing the risk of electrical injuries. The paper will incorporate recent advancements in regulatory guidance and voluntary standards in safety performance measurement. Specific references will include Work Safe Alberta Leading Indicators in Workplace Safety and Health (published in 2015) and US OSHA Using Leading Indicators to Improve Safety and Health Outcomes (published in 2019). The paper will include a method for an organization to benchmark current metrics for its electrical safety program against advanced practices to measure and manage continual improvement.
Effective Job Briefings Improve Safety
Daryld Ray Crow
This paper addresses the importance of job briefings. Recommended key elements to improve job briefings are included to help employers and employees ensure job briefing are effective to help improve safety in the work place. The paper includes answers to questions received when the paper “Checklists Safe Lives” was presented at the 2020 ESW.
Reliability and Safety of Electric Power Systems
Alan M Ross
Statistics show that the more reliable a plant or facility is, the safer it is. This presentation will present the unique connection between reliability and safety from a professional reliability engineering perspective. When asked “Who is responsible for safety?”, most organizations have done a great job of having the answers be “Everyone”. When asking, “Who is responsible for reliability?”, the answer most often is…him or her, but not me. Reliability is usually focused on by the maintenance department or corporate reliability engineering, but very seldom is it considered and organization-wide mandate.
Reconditioning Low-Voltage Circuit Breakers – Are They Really Safe?
David B. Durocher, Thomas Domitrovich
For many years, industrial manufacturing plants in the process industries, along with hospitals, schools and commercial building owners have installed used circuit breakers in panelboards, switchboards, switchgear and motor control centers with reconditioned replacements. Often times, due to the vintage of existing electrical equipment, reconditioned circuit breaker replacements are the only available option. Is this practice safe? Some recognized industry standards such as the Professional Electrical Apparatus Reconditioning League (PEARL) ANSI Accredited Electrical Equipment Reconditioning Standard (EERS) say yes. For Molded Case Circuit Breakers (MCCBs), the recently published U.S. National Electric Code NFPA70-2020 says no. This paper will review applicable global and regional industry standards for circuit breakers and offer clarity around many words including “rebuilt”, “refurbished”, “remanufactured”, “reconditioned” and “renovated” and terms such as “field-modified”. The paper will briefly review design and test standards for new 600-volt class molded-case, insulated case and low-voltage power circuit breakers followed by standards covering accepted practices for reconditioned products, with focused guidance on proper application to assure safe and reliable system circuit protection.
Defining the Role of the “Employee in Charge” in Electrical Safety Work
The Occupational Safety and Health Administration (OSHA) uses the term “employee in charge” 12 times in their regulations. The National Fire Protection Association (NFPA) Standard for Electrical Safety in the Workplace, 70E® uses the terms “employee” or “person in charge” 28 times. The National Electrical Safety Code (NESC) uses the term seven times. The term is important in all three documents, yet none of them define it. This paper offers an analysis of the use of the term in these documents, and details why that role is critical to safe work practices on or near electrical conductors and circuit parts, with particular focus on its function in high voltage work.
Equivalent Formulas for Determining Incident Heat Energy for Various Fault Currents and Clearing Times used in NESC and OSHA Regulations
Marcia L Eblen, Tom Short, Zarheer Jooma
OSHA 1910.269 Appendix E Table 6- Incident Heat Energy for Various Fault Currents, Clearing Times, and Voltages of 4.0 to 46kV: Rubber Insulating Glove Exposures Involving Phase-to-Ground Arcs in Open Air ONLY and Table 7- Incident Heat Energy for Various Fault Currents, Clearing Times, and Voltages: Live-line Tool Exposures involving Phase-to-Ground Arcs in Open Air ONLY and NESC-2012 Tables 410-2 Clothing and Clothing Systems -voltage, fault current and maximum clearing time for voltages 1.1kV to 46kV and 410-3 Clothing and Clothing Systems -voltage, fault current and maximum clearing time for voltages 46.1kV to 800kV were developed using a commercially available computer program. However, the table values are only provided for a few discrete available fault current values. By reproducing the inputs and outputs using the same version of the commercially available software, values for more than those few discrete available fault currents can be produced. Equivalent power formulas can then be developed that will conservatively envelope all the incident energy values for a complete range of available fault currents for each given set of conditions. This provides simplification and ease of use for end users.
Understanding and Getting Involved in NFPA’s Standards Development Process
Diana Jones, David Pace
The objective of this paper is to increase a person’s knowledge of the process, including explaining how anyone can get involved and encouraging them to do so. Standards developed by the National Fire Protection Association (NFPA) are a very important source of information for electrical safety programs and safe electrical installations for a very large number of individuals and organizations. They are widely used by many countries around the world. NFPA 70®, National Electrical Code®, (or NEC®), and NFPA 70E®, Standard for Electrical Safety in the Workplace® are two more commonly known examples, although there are many others. NFPA has a well-established process for the development of new standards and for periodic review and revision of existing ones. Understanding this standards development and revision process is important to everyone involved with electrical safety. It follows a defined set of rules and regulations that moves the standards through the process, and that also encourages participation from members of the public. Most people are not aware of what this process is, or that it encourages public participation. The process is open to anyone and the more involvement from affected individuals, the better the resulting standards. Everyone has their own knowledge, experiences and expertise. All are valuable and should be included in the process.
5-Minute Job – Training an Unqualified Worker For When Things Go Wrong
We have all had those tasks come up that on the surface seems like a very simple 5-minute job. But then things do not go quite as planned. Suddenly, that simple task has now become a major job. People will then tend to start taking short cuts and get complacent in how they complete the repair job. That is when people get hurt or equipment gets damaged. This paper will explain how a very simple task at the author’s house garage to replace two ceiling light bulbs and two garage door opener light bulbs turned into over a one-week nightmare. The parallels to the industrial electrical safety world are phenomenal. The other thing that made this job unique is the worker performing the tasks was an unqualified electrical worker that was working under the direct supervision of a qualified worker in a training mode. This paper will examine all the detailed steps that were taken in compliance of NFPA 70E to keep the worker safe while performing in a training mode under difficult situations. When the job was completed, all electrical safety procedures for hazard risk analysis, job briefing, individual responsibilities, lock out tag out, PPE, and fall protection were followed. No one was injured and the unqualified worker gained a lot of new experience and is now trained to meet the NFPA 70E definition of a qualified worker to perform these tasks in the future. Moral of the story is there is no such thing as a 5-minute job in life. You must plan accordingly.
Arc Flash Incident in Wind Turbine
Ron Zieber, Wayne Oliver
Operation and maintenance of wind turbines present unique electrical safety challenges including: restricted work areas around electrical equipment, work carried out at heights, buildup of static electricity on fiberglass blades, risk of lightning strike hazards, and specialized emergency response skills for incidents in the nacelle. This case study reviews an arc flash incident in a 660kW turbine, triggered by routine cleaning around electrical gear down tower, that resulted significant damage to the electrical equipment as well as stranding a worker on the roof of the nacelle. The incident resulted in changes to safety practices.
Electricity Accidents in Brazil: The Data and Characteristics of Accidents What is Being Done to Change This Scenario
This article carries in essence, the experience lived by the author over 15 years as the head of an association that decided aware lay people and electricity professionals about the risks that electricity offers, in order to reduce the number of accidents of this nature. Using the accident data collected by ABRACOPEL – Brazilian Association for Awareness of the Electricity Danger, and compiled in a document entitled Statistical Yearbook of Electrical Origin Accidents, it was possible to carry out specific actions, using languages aimed to each type of public, accidents target. The conclusion that many accidents can be avoided with low information is part of this work. Also, will be presented some actions that are being or have been carried out over these 15 years, and the results obtained.
Solid State Circuit Breakers – The All-In-One Device that Can Reduce Equipment Damage, Reduce Arc Flash Hazard and Perform the Functions of Other Equipment in an Electrical Distribution System
Jay Prigmore, Doug Ehlers
As the world transitions to a digital age, there is a growing need for a faster and more responsive circuit breaker. Solid-state circuit breakers (SSCBs) recently became commercially available, and can provide various electrical safety improvements including arc flash hazard mitigation benefits compared to mechanical circuit breakers. These performance improvements are achieved by the SSCB’s switching speed. Traditionally, circuit breakers have been manufactured using mechanical parts to make or break a circuit that typically operates in the millisecond range. The mechanical circuit breaker (MCB) has seen little improvement in its operating speed for making or breaking a circuit.
Prevention Through Design, Strategies To Reduce The Hazards Of Stationary Battery Systems Through Intelligent Design
Michael P. O’Brien, John R. Todora
Stationary Battery Systems provide the control and reserve power for modern life as we know it. These systems provide control power for switchgear and automated controls, the power for field flashing of generators, emergency lube oil and seal oil pumps and other critical motors, the reserve power for UPS systems, and the operating power for critical communication systems. In short these battery systems make modern life possible, and they surround us. Stationary Battery Systems present unique maintenance hazards due to the availability of high currents, lethal voltages, flammable/explosive gas, and corrosive chemicals. All work on stationary batteries is energized work. This paper will show that we can make the stationary battery systems safer today by implementing a few well thought out, yet simple and low-cost system design changes that reduce the potential for injury and death while ensuring that the battery system can be safely maintained throughout its service life. Another major concern addressed in the paper is the designing of simple protection devices that guard against Human Performance failings. “Things Happen”. By learning from experience, we can provide simple design changes that reduce the potential of things like short circuits caused by dropped wrenches. We will also address the need to guard against fixing one problem only to inadvertently produce another.
Arc-Flash PPE – A Simplified Constant Energy Line Table Method
Remi Halle, Kirk Gray, Daniel Roberts, Marcelo Valdes
One of the challenges faced by employers and workers is determining the appropriate rating of arc flash personal protective equipment (PPE) when an engineering calculation has not been performed. Some standards include tables to assist the user in selecting arc flash PPE for specific equipment types and voltage ranges. However, to use these and similar tabular methods requires the user to determine the fault current and the fault clearing time. Determining these values is at best difficult for the electrical worker, and in some circumstances, all but impossible. This paper discusses a proposed simplified table method to determine the required arc flash PPE requirements based on a constant-energy boundary, and alternatives considered in the process of creating the proposed table. The method requires identification of readily available electrical system characteristics in addition to the nominal voltage and equipment type to use the table. The method does not require the user to calculate the available fault current or determine fault clearing times. The method also addresses the effect of electrode configuration on the incident energy introduced in IEEE 1584TM-2018 Guide for Performing Arc -Flash Hazard Calculations and low arcing current, which are currently unaccounted for in the tables commonly used today.
Lessons Learned Developing Standardized PPE Levels and Task Specific Risk Assessments for a Multinational Company
John Mason, Joshua Kerr, Donald Lockhart, Elihu “Hugh” Hoagland
This paper looks at the process and problems the authors encountered when developing and standardizing PPE levels and task-specific risk assessments for a multinational company that operates large facilities with complex electrical systems around the world. The obstacles of synchronizing a coherent electrical safety program with national standards, international test methods and certification processes and even different language for arc flash/electric arc/electrical arc were resolved to provide consistent requirements that met a corporate NFPA 70E/OSHA 1910.269 program adapted to EU and other international norms. These risk assessment learnings will provide an extremely effective tool for minimizing risk and protecting workers, when applied correctly. For this to happen, personnel of all levels need to have a clear understanding of the company’s expectations when it comes to assessing risk and selecting PPE for a given task. The company can accomplish this by standardizing PPE criteria and risk assessments for common tasks on a given piece of equipment. Doing so requires a significant amount of upfront and ongoing work, but will greatly reduce the chance of errors in common tasks and provide a template for future risk assessments.
An Accident Waiting to Happen
Homemade equipment – to save money
Non-performing craft – because management doesn’t want to have the hard discussion
Unqualified personnel – because we need the bodies on the job
A lack of formal procedures – because they take a lot of time and effort to write
A deviation from lockout/tagout protocol – because it was quicker
Any one of these can be the prelude to a serious electrical incident. Mix them all together and you have a recipe for a catastrophic failure which resulted in a near fatality and a cost to the company of millions of dollars.
A State by State Comparison of Occupational Electrical Work Fatalities
Electrical workers are fatally injured from multiple causes and electrical work is a subset of all occupational electrical fatalities. This work is a state by state comparison of 2011-2018 US Bureau of Labor Statistics (BLS) fatal occupational injury statistics for workers classified as “electricians.” The top state 2011-2018 BLS fatal occupational injury statistics illustrate that the BLS fatal injury data for electricians generally reflects the state fatal occupational injury data for all workers. State licensing requirements for electricians demonstrate that the eleven states which require a formal apprenticeship or education are among those states with lower fatal injury rates for electricians. Correlations and implications are also explored between “electrician” fatal injuries and: 1) state licensing and continuing education requirements for electricians and electrical contractors; 2) OSHA-approved state plans; and 3) state political ideology. Fatal electrical accident records from 2011-2018 OSHA accident reports which involved electrical work are discussed for the states which did not record any electrician work fatalities. How to reach electricians in higher risk states and how to reach non-qualified workers who do electrical work are addressed.
Electrical fatality rate and epidemiologically consideration by electric shock in Japan, 2015-2017
An electric shock accident may occur when a part of the human body touches a charged object, while performing electrical maintenance and replacement activities. This accident can cause an electrical injury, which would require rest and absence of more than 4 days from work, or a fatality. The total number of electrical fatalities from 1959–2017 is 7635 in Japan. The number of electrical fatalities in 2015, 2016, and 2017 were 11, 11, and 9, respectively. Hence, it is necessary to find measures to eliminate electrical fatalities to prevent the unnecessary loss of human life. However, it is challenging because most fatalities occur in construction and manufacturing units. In this study, we evaluated the electrical fatalities between 2015 and 2017. These results will aid in establishing preventive measures for electrical fatalities in the future
Comparison of IEEE 1584-2018 Predictions with Tests on Real-World Equipment
IEEE 1584-2018 contains a significant update to industry models for predicting the incident energy from arc flash. These models include different box sizes, voltages, and electrode geometries. Predictions from these models will be compared to tests done on low-voltage and medium-voltage equipment. Equipment includes panel boards, circuit-breaker cubicles, metering equipment, live-front switches, live-front transformers, and open-air scenarios. Results will show what input assumptions are most applicable for each type of equipment (including VCB vs. HCB vs. VCBB). Where differences between tests and model predictions exist, modifications of analyses will be considered within the 1584-2018 framework.
Temporary Test Equipment, Risk of not Maintaining an Electrically Safe Work Condition
As part of preventative maintenance and start-up activities, electrical test equipment is brought into an Electrically Safe Work Boundary to perform testing to confirm the functionality of the system and critical components. When the test equipment is performing the test, a voltage or current is applied to the electrical equipment, thus destroying an electrically safe work condition. This paper will evaluate the potential sources of power that test equipment can supply to equipment, determine which test sets could be considered hazardous, and how qualified workers can protect themselves from these hazards.
The Prevention through Design Engineering Student Initiative
This annual initiative solicits proposals from Master Degree and Ph.D. candidates on concepts in engineering design solutions for reducing the risk of electrical mishaps and injuries. The selected recipients for 2021 will present their proposals.
Analyzing Accidents Among Electrical Contractors: A Data Mining Approach
George Mason University, USA
To prevent accidents, one needs to know the usual causes of accidents. The significant amount of safety data being collected on constriction sites – accident reports—provides a valuable source of information for researchers seeking to better understand the root-causes of accidents. However, the volume of data provided by accident reports can mushroom and quickly become “big data”. Furthermore, since the relationships between accident-causation factors can be nonlinear and can include high-order interactions, many common statistical techniques would fail to reveal hidden patterns in the data. Unlike humans, machines can handle large amount of high-dimensional data to assist safety practitioners with informed decisions. Therefore, this study applies machine learning algorithms (MLAs) to: (1) delve deep into accident reports to identify chains of events that lead to accidents among electrical contractors; (2) develop predictive models to forecast outcomes of an accident based on limited attributes in similar situations; and (3) determine techniques to improve the accuracy of predictive models when the costs of errors are unequal, and the data is highly imbalanced. The findings of this study contribute to the current body of safety knowledge and practice in several ways. First, this study reveals the main trends of accidents and injuries among electrical contractors in the U.S. construction industry. Second, the classification and regression trees developed in this study can be utilized to find a subset of influential variables that appear to explain differences between fatal and non-fatal accidents for different specialty contractors. The identified rules can be used by practitioners to understand and communicate the chain of causes leading to a fatality and to implement feasible prevention strategies to mitigate the hazard. Ultimately, the predictive models developed here will help decision makers in predicting the severity of accidents and assist them with prioritizing more hazardous situations.
Novel Pre-Diagnosis Strategies for Medium-Low Voltage Arc Flash
University of Electronic Science and Technology of China
With the development of distribution networks, the high power density equipment is becoming more concentrated in medium-low voltage level, which may lead serious safety risks such as arc flash incidents. To better protect personnel and equipment from the hazards, a fast and reliable electric arc detecting and locating method is thus essentially to be developed. However, due to the issues such as low sensitivity, delayed detection, complex structure, susceptible to interference by other sources, the application of traditional approaches, especially in weak system source and high arcing resistance featured medium-low voltage arc flash, are severely restricted. To avoid those limitation, a spatial magnetic field analysis based hybrid preemptive detection method of arc flash are fully investigated in the work. With the categorizing analysis of geometric configuration, mathematical modeling incorporated MHD approach is developed, which able to identify whether the arc occurs between wires or between the wires and the mounting accessories of the box due to the insulation breakage or aging. With a series actual cases based simulations, the transient dynamics of arcing current, and the relationship among arc fault location, discharge types and magnetic field is derived, which offered valuable information for medium-low arc mitigation and hazard prevention.
Power Consumption at 230 V Single-Phase Can be Made as Safe as 120 V Systems
Rajesh M. Pindoriya
In this paper, the safety, and economic issues of power consumption at single-phase 120 and 230 V are discussed. Majority of power consumed in the world is at single-phase 120 and 230 V. The only reason USA and Japan opted for consumption of power at120 V was because it is safer as compared to 230 V. It is obvious that at 120 V it requires almost double amperage to supply the same amount of power. Hence, at 120 V it requires four times more cross-sectional area of the copper conductor to limit the same magnitude of heat/I2R losses. The rise in the temperature of the conductor is restricted by the maximum permissible temperature of the insulation. Distribution of power at 120 V is, therefore, an extremely expensive venture. Additionally, the higher magnitude of current leads to higher magnetic fields indoors, considered to be unsafe for the human over a long time. With the development and installation of modern inexpensive protective devices, for example, Miniature Circuit Breakers (MCBs) and Earth-Fault Relays (EFRs), power consumed at 230 V can be made as safe as 120 V. The EFRs trip the circuit instantly in case a person gets a shock. Electrical safety of human being can thus be achieved by the mandatory application of modern devices.
TN-Island System Shipside and TT-System Shoreside for Cold Ironing
Sapienza University of Rome, Italy
The cold ironing system that allows the switch off ships generators in port, is a promoted solution to reduce ships emission in ports. The grounding system for the cold ironing could allow risks of transferred touch potentials and of the galvanic corrosion on ship propellers. This paper deals with a solution for limit the two risks that provides a TN-island system shipside and a TT-system shoreside during the ship mooring in ports. The TN-island system consists in a connection via resistor of the neutral point of shore transformer exclusively with the grounding system of the ship. Two grounding systems operate in cases of faults. A shipside ground fault finds a grounding system TN-island, while a ground fault on the shore-side finds a TT-system. This solution allows limiting considerably the potential transfer and DC current circulation.
Reducing Wildfire Risks with AI-Based Integrated Satellite & Drone Vegetation Inspection
Western Norway University of Applied Sciences, Norway
Vegetation Management is a significant preventive maintenance expense in many power transmission and distribution companies. Lack of proper and timely vegetation management cause higher risks of wildfires, electrical faults, and power outages, in addition to safety threats for humans and animals. Traditional Vegetation Management practices have been demonstrated to be ineffective and are rapidly becoming obsolete due to the lack of situational awareness on vegetation and environmental conditions. The rise of high-resolution satellite imagery data and machine learning advancements brings the opportunity to close the loop with continuous data-driven vegetation monitoring. Satellite-based vegetation monitoring reduces the overall inspection cost and provides more frequent situational awareness on a broader spatial scale. Despite the decreasing costs of high-resolution satellite imagery, artificial intelligence methods need more improvements to locate trees accurately and estimate their height and type. Our study fills the knowledge gap and provides utilities with an AI-based solution to automatically detect vegetation encroachment within power lines right-of-way and improve power system reliability and resilience, respectively.
Powering through Wildfires: An Integrated Solution for Ensured Safety and Resilience in Power Grids
George Washington University, USA
Safeguarding the nation’s electrical infrastructure and personnel against natural and man-made disasters, and ensuring a continuous, reliable, and resilient supply of energy is among the top priorities. In recent years, wildfire hazards have been remarkably threatening the safety and security of electric power grids demanding innovative frameworks and novel mechanisms for ensured resilience. Our proposed approach focuses on mitigation of wildfire disruptions that once occur can jeopardize the safety of electrical equipment and the personnel. The proposed framework firstly offers a comprehensive wildfire characterization package that can temporally-spatially monitor and analyze the wildfire behaviors, i.e., wildfire intensity, wildfire arrival time, and wildfire binding paths from ignition points to electrical equipment. This allows power system operators to make proactive decisions before the fire approaches the electrical elements, e.g., power transmission and distribution lines, and threatens their safety and wellbeing. In addition, a next generation decision support tool for wildfire management in power grids is proposed such that various local resources, i.e., distributed renewable energy resources, and energy storages, can be effectively employed to mitigate the wildfire disturbances in power grids. The proposed integrated solution technology ensures a significant reduction in power outages, if any, and also enhances the safety and resilience of the power grid and the operating personnel.
Enhancing Electrical Safety through EV Fleet Scheduling for Resilient Response to Natural Disasters
North China Electric Power University, China
In recent years, extreme weather events, such as storms, hurricanes, have caused large-scale power outages, as well as tremendous social and economic losses. For example, in 2012, after Hurricane Sandy struck the East Coast of the U.S., approximately 8.35 million customers were reported without power. Prolonged power outages caused by natural disasters can also impose critical threats to health and public safety, and could potentially compromise national security. The resulting tremendous economic loss and significant life risk have highlighted the importance and urgency to enhance power grid resilience. Electric vehicles (EVs) have great potentials to be employed as grid-support resources during power grid emergency operating conditions to supply the critical loads and enhance the resilience of distribution system via a swift disaster restoration. This research aims to address the optimal routing and charging/discharging scheduling problem of EV fleets for resilient response to natural disasters. The optimization problem can be formulated as a Markov decision process and solved using deep reinforcement learning and operations research. With optimal routing and scheduling, EVs can provide rapid restoration at outage islands without waiting for repair of damaged components or recovery of the main grid, providing tremendous mobility and exibility in enhancing distribution network resilience.
Object Detection and Distance Estimation for Physical Protection against Substation Attacks
University of Pittsburgh, USA
Unfortunately, most of the electrical substations are lacking essential protection in these days. A physical attack on a substation could result in power outages and failures in large parts of the country. In fact, since 2013, there have been four known attacks on substations around the country—the most recent of these attacks happening in November 2014. These attacks point out the lack of protection on substations and open the discussion on the best way to secure these electrical hubs. The construction of Air Insulated Substations (AIS) entails special requirements for the minimum distances between the different phases in live parts as well as between live and earthed/grounded parts. This minimum distance and the distance between objects are critical in the live substation’s maintenance and physical protection from substation attacks. We propose a technique for distance measurement for objects in a substation using the camera to estimate the distance between objects like crows, attackers and assets. However, many challenges are encountered in dealing with distance measurement and cost, both in equipment and technique. The use of surveillance camera to measure an object’s distance is convenient and popular for human-made obstacle avoidance and clearance satisfaction for crows. The calculation of distance considers angular distance, the distance between cameras, and the pixel of the image. This research study proposes a deep learning method that measures object distance based on trigonometry, facing the human (or object) using image processing and stereo vision with high accuracy, low cost, and computational speed. The proposed technique can implement in real-time computing systems of the substation protection system. It can determine the safe clearance distance between obstacles and assert the required alert for substation operator in case of human-made physical attacks.