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Let's face it —we're all power hungry. How can we not be, given the fact that so much sophisticated equipment and controls are being used in so many industrial, commercial, institutional and government facilities? They all rely immensely on electrical service, and count on their systems not to let them down. But they often do and the consequences aren't good. They include interruptions in their production processes, equipment damage, downtime, scrap and capacity losses. The most common culprits are voltage sags, power interruptions and voltage flicker.
Voltage sags occur most often and simply stated are a short-term reduction in voltage. They're often caused by fuse or breaker operation, motor starting, or capacitor switching. What they mean to productivity are interruptions to sensitive equipment such as adjustable-speed drives, relays and robots.
Power interruptions are zero-voltage events often brought on by weather, equipment malfunction, recloser operations, or transmission outages. Interruptions can occur on one or more phases and usually last less than 60 seconds.
Voltage flicker, on the other hand, is rapidly occurring voltage sags caused by sudden or big increases in load current. Rapidly varying loads that need a lot of reactive power such as welders, sawmills, wood chippers, metal shredders, rock-crushers, and even amusement rides are most vulnerable. Voltage flicker can result in a visible flicker in lights and the shutdown or malfunction of other processes, as well.
According to Kim White, Marketing Manager for Staco Energy Products Co., blackouts are a small percentage of electrical problems. "It's the small fluctuations that destroy machinery the fastest," she points out. Those small glitches, she says, can cause machinery to lockup, corrupt data, and dramatically shorten the life of any equipment subjected to it. Couple increased repair and replacement costs with the possibility of lost or corrupt data, she contends, and you're looking at a problem that can cost U.S. companies billions every year.
White concedes that it can be tough to truly understand the costs, because power problems have been with us since the times of Edison, and are simply considered the cost of doing business. Indeed, the more computerized equipment used, the more susceptible your company may be to power quality problems, she concludes.
Daylight savings
A significant savings can be seen by installing corrective equipment, White believes.
The correction of power quality problems, she says, can range from simple fixes like redistributing equipment or rewiring and upgrading the electrical system within a facility, to installing larger power conditioners, UPS systems, power factor systems, or harmonic filters. The best way for most companies to determine the extent of their power problems, however, is to have a power quality analysis performed on their facility by a reputable analyst.
To that end, there are many options for contractors. S&C, for example, offers systems that protect not only data centers, but large industrial facilities, such as semiconductor chip fabs, pharmaceutical manufacturing, and automotive assembly plants, insuring the continuity of the manufacturing process. According to the company, these systems — such as the PureWave UPS System and the PureWave Source-Transfer System — can be installed indoors or outdoors without modification.
American Power Conversion (APC) also provides protection against some of the leading causes of downtime, data loss and hardware damage. The company advises that the best way to prevent it is employing an Uninterruptible Power Supply (UPS).
APC Communication Specialist, Nicole Gidden, notes that UPS systems isolate the critical loads from electrical aberrations of all types — voltage and frequency fluctuations, electrical noise, power dropouts, and surges and spikes.
"With [our] UPS, for instance, you can monitor and log voltage and the number and type of electrical disturbance," she says. "You can have your network-enabled UPS alert you in a variety of ways based on thresholds that you set. You can also keep months of logs like a Power Event Summary, Power Event Analysis, and Voltage Analysis. This information has been used many times by companies as evidence for those wishing to improve the quality of power supplied by their local utility [authority]."
The Liebert brand from Emerson Network Power also offers an array of UPS solutions. In addition to being a source of backup power in the event of an outage, the second function of Liebert UPS systems is power conditioning, says Michael Wassermann, the company's Director of Marketing. In most applications, the UPS removes sags, noise, and other power quality problems that can damage equipment or degrade performance, he adds.
A third function is real-time remote monitoring and controlled shutdown of protected equipment. Ethernet-based communication systems, such as Liebert OpenComms Web Card and Liebert Nform allow for monitoring of remote power devices and provide real-time event notification and alarms, among other features.
The Square D brand of Schneider Electric also offers power protection products and training. Their PowerLogic Series 4000 Circuit Monitors (CM4250 and CM4000T) provide information on all aspects of power quality and capture and store multiple levels of information on each event to help pinpoint the source of a problem. They apply the latest IEEE and IEC power quality standards to generate the information you need to improve power system reliability, the company points out.
Conversely, the CM4000T detects both oscillatory and extremely fast impulsive voltage transients. Even shutting down the associated PC software won't stop ongoing monitoring and data capture, the company adds.
Other benefits include a power quality summary; which combines each power quality category into a single index to indicate the general level of power quality at the metering point. Disturbance direction detection is also included and indicates whether a disturbance occurred upstream or downstream of the meter while giving the contractor a level of confidence on the diagnosis.
According to Jon Bickel, Sr., Staff, Electrical/Electronics Engineer, when the meter is placed at the point of common coupling, harmonic power flows help determine whether harmonic currents originated inside the facility or out on the utility grid. The CM4000T also measures voltage flicker according to IEC standards and can determine the level of flicker due to internal and external influences, the company adds.
Square D's Director of Power Quality Correction, Rudy Wodrich concludes: "Our industrial customers make a large capital investment in their equipment and it's very important that they understand what's happening on their electrical systems. Sophisticated equipment can give them a better idea of what's going on in their electrical systems and protect their capital investment and prevent losses from downtime."
Wassermann echoes these sentiments: "As network services become essential to business continuity and the cost of downtime escalates, a dependable UPS system is essential to protecting data centers and server rooms from unplanned downtime and equipment damage."
author: By Erin Harrington