It wasn’t long ago when flashing digital clocks were the most likely power-quality-related effect of an interruption. Today more than 70 percent of homes have computers, and nearly that many have Internet access.
Whether it came from Heraclitus in 470 B.C. or François de la Rochefoucauld in the 17th century, the adage “the only thing constant is change” usually directly affects the power quality level in a facility.
The power quality phenomena categories in IEEE Standard 1159 2009, “Recommended Practice for Monitoring Electric Power Quality,” are often used to define what to look for, how to look for it, and how to protect a piece of equipment from it.
While conducting an investigation recently to determine why a piece of equipment in a telecom center was resetting occasionally from a perceived low-voltage condition, I actually was able to review the facility’s electrical drawings. Sometimes, the operations manager has no clue where they are.
One of my responsibilities is to provide new employees with an abbreviated power quality course, so they know enough to relate the basic concepts to their particular job function. I do not want to overwhelm them by trying to turn them into power quality engineers.
At trade shows and distributors, you undoubtedly hear about the latest and greatest product offerings from a large contingent of vendors in electrical contractors’ domain, including those that sell power quality (PQ) monitoring equipment.
Several of my articles recently have been about low-voltage direct current (DC) powered equipment and telecommunications systems vulnerabilities to power quality phenomena, especially with regard to transients, noise and other types of electromagnetic interference (EMI).
During The winter holiday season, houses are often decorated inside and out with little blinking lights. But, when the regular house or commercial lights blink or flicker, that’s a different story, and it is about to change.
If one searches for power quality tools on the internet,- the most common results will be for equipment, such as digital multimeters, harmonic analyzers and, most often, power quality analyzers or monitors.
When most people think of the source and effects of power quality problems, they think of voltage interruptions, harmonics, transients, sags, swells and even flicker, all of which are phenomena that occur on the alternating current (AC) voltage system.
Last month, I covered common power quality phenomena with regards to the National Electrical Code (NEC). Two articles address specific topics related to power quality: Article 647, Sensitive Electronic Equipment, and Article 708, Critical Operations Power Systems (COPS).
Even after 30 years-plus of power-quality monitoring, no national design code standard exists for minimizing the impact of power quality phenomena; there isn’t an equivalent of the National Electrical Code (NEC) anywhere.