When using a power quality monitoring instrument, there are some “gotchas” to watch out for; otherwise, your efforts can either be wasted or, perhaps worse, misleading by coming to conclusions that aren’t valid.
When it comes to new construction of the electrical infrastructure within a facility, the National Electrical Code (NEC) is the most common source of rules and regulations with regard to what to do and how to do it.
With the Institute of Electric Efficiency reporting more than 36 million smart meters installed from 2007 through May 2012 and a target of 65 million by 2015, it appears that smart meters are here to stay.
On most distribution networks (except maybe in rural areas), the voltage levels typically reduce to a couple of percentage points from nominal when the sun rises, people wake up and they start using more electricity. Conversely, as the sun sets, the voltage creeps back up, and by 10 p.m.
Part of every significant construction project and major renovation should be the commissioning of the electrical systems (or recommissioning for renovations) along with the heating, ventilating and air conditioning (HVAC); mechanical; fire alarm; and other systems in the facility.
There is a saying that, when you point your finger, three fingers point back. When a facility encounters a misoperation that the manager thinks was caused by the electric power, the first reaction is to point the finger at the utility.
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).