Arc-flash reduction methods must be considered prior to working on energized electrical equipment for personnel safety. The idea behind energy reduction is to place energized electrical equipment in a state where less arc energy is available when an arcing fault occurs. These techniques range from the obvious (de-energize!) to more complex and costly engineering solutions. NEC Article 240.87-2011, initially titled …
An electric arc or arc flash occurs when a high voltage causes ionization of a gas — for example, air. Ionization turns an ordinarily nonconductive gas into conductive gas that can carry a sustained current. The color of a typical arc flash in air is very distinctive. This is because air is composed of 21% oxygen and 78% nitrogen; oxygen …
Matters of NERC PRC and NERC CIP compliance intersect during protection system testing on substation networks. In the modern regulatory environment, the benefits of computer-based relaying are challenged by the costs of cyber security and disrupted or insufficient relay testing practices. The way forward demands interconnected data and the ability to track critical metrics automatically. Organizations can modernize while ensuring …
Batteries serve as the main source of power in a substation in the event of an AC outage. They power critical loads and equipment like relays, indicator lamps, circuit-breaker control, motor operators, SCADA, event recorders, etc. As the battery is truly put to the test only during an outage, it is important to monitor battery health on a regular basis …
We find ourselves in a time where everyday life has become principally reliant on the uninterrupted supply of electricity. Powering our homes, sustaining mass transit infrastructure, and keeping the lights on at our healthcare facilities are prime examples of the importance reliable power holds to our way of life. But as our demand for electric power is ever-growing, our requirement …
The share of wind power in total electric power generation is expected to increase, and with that comes a requirement for this carbon-free source to be more reliable. The wind turbine, which is the most important component of a wind power system, is exposed to harsh environmental conditions and electrical transients such as lightning strikes. Naturally, understanding the lightning protection …
The growth in renewable energy power generation will continue into the future. What has been lacking is focus on the electrical hazards in construction and fabrication, commissioning, operation, and maintenance. However, requirements in NFPA 70E, Standard for Electrical Safety in the Workplace and CSA Z462, Workplace electrical safety Standard do apply to renewable power generation. ARC FLASH AND SHOCK HAZARDS …
A test technician’s toolbox can never have too many options. The more ways we can detect or confirm a problem in a piece of equipment, the better. Early in my career at Duke Energy, I was never satisfied with just one test result indicating a problem, and I often second-guessed myself as to whether the equipment was bad or if …
Circuit breakers used in low-voltage applications include air circuit breakers, insulated-case and molded-case circuit breakers, and miniature circuit breakers. Air circuit breakers or low-voltage power circuit breakers typically function as the incoming device on a low-voltage switchboard. In the event of an overload condition or short circuit, current sensors in low-voltage power circuit breakers measure high currents and send the …
Low-voltage circuit breakers are predominant in virtually every electrical power system. A 2008 NETA survey and associated IEEE paper showed that 22% of these breakers did not follow their time-current characteristics, and 10.5% did not operate at all when service-aged maintenance was undertaken. The majority of failures were mechanical in nature; this indicates regular maintenance must be a priority. Low-voltage …