Electricity Today is a leading electrical transmission and distribution magazine distributed subscribe free of charge to North American T&D electric utility engineering, construction and maintenance personnel, and high voltage T&D consulting engineers.
In the Latest Issue
How utilities can yield significant operational benefits
BY JEFF WALZ, Siemens Smart Grid
As North American electric utilities continue to transform their existing electric delivery assets into a smarter grid, strong emphasis is placed on systems, products, and services that provide value in automating and managing the electric distribution network. Within this context, utilities are focusing on four main themes in distribution: reliability, efficiency, safety, and interoperability.
These themes relate directly to the operational objectives of distribution utilities but achieving these goals is becoming increasingly challenging. North America’s electricity grid infrastructure is aging, with many assets near or beyond their expected lifespans. Customer expectations with respect to reliability and power quality continue to grow, not only for commercial and industrial but for residential consumers as well. Moreover, the avail- ability and penetration of distributed energy resources, including renewable generation, is on the rise.
Misconceptions about using flame-resistant clothing
BY DAN BONELLI, Cintas Corporation
According to Michael Hyland, chair of the National Electrical Safety Code (NESC) and vice president of engineering services with the American Public Power Association, a 1970s electrical utility commercial depicted a worker sporting a gold necklace and polyester clothing. Hyland notes that today, that type of dress would be unthinkable, as it poses a huge risk to residential, commercial, and industrial electricians.
The power industry has gone to great lengths to help protect electrical workers thanks to organizations such as the National Fire Prevention Association (NFPA) and Edison Electric Institute (EEI), and safety codes such as the National Electrical Safety Code (NESC) and the National Electrical Code (NEC).
However, the industry still has a long way to go and the Occupational Safety and Health Administration (OSHA) recently published an update to its Occupational Safety and Health Standards part 1910.269: “Electric Power Generation, Transmission, and Distribution”, which will certainly accelerate positive change.
Too many utility employees, including linemen, circuit design engineers, and tower technicians, still work without the proper personal protective equipment (PPE) required to help reduce the likelihood and severity of injury during an accident.
To help maximize employee safety and minimize liability in homes, businesses and factories, this issue’s Lineman Safety Channel addressed the most common misconceptions about arc flash protection and the use of arc-rated clothing.
Optimizing conservation benefits through AMI
BY MELODY TOMKOW, Aztech Associates
The conservation benefits of ‘real-time’ electricity consumption information provided by home energy monitors, also known as in-home displays, have been studied repeatedly over the past decade. Recent studies such as the NV Energy’s “2011 Annual Demand Side Management Update Report” report a household electricity consumption reduction of 3.5 percent to nine percent.
Additionally, a well-known survey of existing U.S., Canadian and Japanese studies entitled, “The Impact of Informational Feedback on Energy Consumption — A Survey of the Experimental Evidence”, published by the Brattle Group, shows an electricity usage reduction of seven percent.
However, electric utilities are still challenged to draw applicable meaning from this plethora of information. While the studies clearly demonstrate conservation benefits, the variables across studies—from the range of methodologies to the analytical models used, and the constant evolution of the Smart Grid make it nearly impossible to develop a robust synthesis of results. Importantly, there has been no review that adequately delineates the divergent conservation benefit of advanced metering infrastructure (AMI), connected in-home displays (IHDs) and non-AMI connected IHDs.
Reduce common risks and maintain system reliability
BY SARA SANKOWICH, Unitil Corporation
Most North American electric utilities understand that vegetation management is a key factor in maintaining system reliability. While many utilities have designed and implemented vegetation management programs to mitigate risk on an ongoing basis, successful execution of these programs requires specialized staff with forestry expertise, as well as cross-team collaboration.
Utilities can help ensure a successful vegetation management program by being aware of risks—and, conversely, best practices—that exist in ongoing program management. Awareness of these practices can increase understanding and process efficiencies for system arborists, other utility departments and utility leadership, and line crews alike.
Enhancing protection using directional faulted circuit indicators
BY CHRISTOPHER EVANICH, Thomas & Betts
Underground electrical networks provide reliable service to end users, but create problems for utility personnel in locating faults. Electric utilities who utilize an underground network could spend several weeks trying to locate a fault or potentially not even be able to locate it until a second fault occurs.
A directional faulted circuit indicator (DFCI) is a beneficial piece of equipment in an underground network for assisting line crews in locating faults. A conventional faulted circuit indicator (FCI) is not as useful since the device does not have any directional element. The purpose of a DFCI is to detect faults on the underground network in only a specific direction. Since a fault can occur on any part of the network, directional capabilities are especially important on underground networks.
Sweep frequency response analysis: Reliable demagnetization of transformer cores
BY MARKUS PÜTTER, MICHAEL RÄDLER, BORIS UNTERER, OMICRON electronics GmbH
Whenever a power or distribution transformer is isolated from the power system, it is very probable that residual magnetism remains in the core due to the phase shift. However, residual magnetism also occurs when performing winding resistance tests.
Since manufacturers use these measurements in their routine testing and these tests are typically performed for on-site condition assessment, transformers can be regularly influenced by the effect of residual magnetism.
Residual magnetism leads to high inrush currents which put a great and unnecessary load on the transformer. Additionally, a large number of diagnostic measurements are affected by residual magnetism. As a result, a utility can have difficulties obtaining a reliable condition assessment of its transformers.
Therefore, utilities should demagnetize the transformer before re-energizing it or performing diagnostic measurements. Within the last few years, the first testing devices have been launched which allow practical demagnetization of transformers on-site.
The 2014 Transformer Report highlights the importance and the effect of residual magnetism and increases awareness of the associated risks with re-energizing transformers after an outage.
Removing hazards caused from in-vehicle computing
BY SCOTT BALL, Motion Computing
No utility company would send a worker out in a truck with a known safety defect. North American electric utilities may not realize, however, that by failing to ensure that computing devices are used safely within their vehicles, management could be putting their employees and the public at risk. Even worse, if an accident was to occur, the utility could be held liable.
Access to mobile computing is now the rule rather than the exception. The latest generation of mobile-friendly applications has made computing devices essential for connecting workers with peers, receiving and fulfilling work orders, reporting problems, and managing inventory. As electric utilities adjust their workflows to take advantage of the power of mobile computing systems, a dangerous side effect exists—a growing likelihood that workers will use their device while driving the utility vehicle.