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NOMEX protective garment

Advanced protection against electromagnetic exposures and electric arc

HAZARDS AROUND

While working live in the energized grid, presence of voltage around the workers requires special attention. However, live-line (live working) techniques are widely applied for decades, several accidents in the past prove that the level of safety must be improved to minimize the number and seriousness of injuries in the future.
In the high voltage grid, bare-hand method is a common technique for safe live work. In the surroundings of any energized equipment,...

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2024 CE Code Training - Better Understanding of the Rules

CE Code training is intended to do a lot more than instruct about what changes have taken place since the last time Canada issued a national electrical code. We are producing a series of courses across Canada by one of Canada’s leading experts on the 2024 Edition of Canada’s Electrical...

Counterfeiting Kills

Each year, the counterfeiting of well-known brands and products continues to rise, creating an even more threatening problem. Such well-known counterfeited brands, including consumer safety and critical electrical products, are estimated to be five to seven percent of world trade. The International...

Electrical Protection

Protecting Industrial Control Circuits

Addressing relay challenges with the modern technology

BY MARK STEPHENS & ALDEN WRIGHT, Electric Power Research Institute

In 2009, the Electric Power Research Institute (EPRI) began an effort to create improved alternating current (AC) “ice cube” relays that could withstand voltage sags without dropping out.

Their white paper entitled “AC Ice Cube Relays Applied for Improved Power Quality” outlined the basic design and vulnerability of these common devices that often appear in modern industrial control circuits. These are called “ice cube” because they are housed in clear plastic having the appearance of an ice cube (see photo).

Similar appearing relays with direct current (DC) coils are generally robust to common power quality problems as long as their corresponding DC power supplies are robust as well. However, “ice cube” relays with AC coils have shown extreme sensitivity to voltage sags.

With an average dropout at or near 70 percent of nominal...

Electrical Protection Articles

Generator Protection

Modernizing Protection for Aging Generators

As the electrical grid continues to evolve, the challenge of maintaining effective protection for aging generators becomes increasingly significant. Many older generators operate with potentially outdated protection schemes that may not meet the current standards of efficiency and safety. This...