One of my favorite scenes from the “Wizard of Oz” is when Dorothy stops at the traveling magician’s (soon-to-be Wizard’s) trailer. He tells her future by looking into the crystal ball while rummaging through her belongings for information about her when she closes her eyes. The following article has a similar origin.
At present, the future of power quality monitoring is based on what can be seen at trade shows, conferences, and Web sites of the many power quality instruments and mitigation of equipment manufacturers. An Internet search using the keyword “power quality” will yield more links than you will have time to read.
This article is also inspired by the many recent power quality articles in business journals and newspapers, including Business Week and the New York Times. Power quality has been brought into a new light as a number of economic forces have come together. Foremost is the significant increase in information technology equipment, which numerous sources (including the Federal Reserve chairperson) credit with having contributed to the unprecedented increase in U.S. productivity. The flip side of this is that businesses are relying more on equipment that is both a contributor and victim of power quality phenomena, as mentioned in IEEE Std 1100 (also called the “Emerald Book”). Businesses are now competing in a global economy, increasingly operating 24x7, or 24 hours a day, seven days a week. Figures quoted in the millions of dollars per minute for downtime are common. Uptime of six nines, or 99.9999 percent, is the new buzzword.
“Reliability” and “power quality” are now blurring together. “Reliability” events were typically longer term and also the metric used by Public Utility Commissions (PUCs) to evaluate electric utility companies’ performance. As demand begins to exceed capacity (more electricity consumed than generated), concerns over rolling-blackouts and system stability are now entering into the power quality arena. This has been further complicated by deregulation.
Distributed generation has received significant press lately as a means to use standby generating capacity during peak loading times. However, the utilities have raised concerns of system stability and protection, and the effects on power quality.
The net result is that more people are monitoring electricity for more reasons. The portable power quality monitors went through a change about 10 years ago when energy and demand information was combined into the PQ monitor, rather than having a separate portable instrument monitoring those parameters. This same change has recently happened in the watt-hour meter market, where some power quality information is now being computed in the digital watt-hour/demand meters.
Instead of just having one meter at the service entrance, submetering is being deployed throughout office complexes and factories to more accurately account for where the electricity is being consumed. The development of lower-cost, permanently installed power quality monitors has allowed these devices to be economically used throughout facilities also, rather than just at critical loads and the service entrance.
So, more data is good? Maybe. It also can lead to analysis-paralysis or information overload. When more parameters are being monitored on more circuits with faster data sampling rates, it results in gigabytes of data where there was previously a single monthly utility bill . Data can be retrieved from monitors that are connected via local area networks or anywhere in the world via the Internet. The effects of a large motor start in one part of the building can be seen on the paint spray booth in another part of the building. More data from more places needs to be correlated and analyzed.
This has led to another development in the power quality monitoring market —the evolution of data to information to answers. You don’t have to weed through countless waveforms to find the cause of a problem. Monitoring systems can send you an e-mail or page you with what caused the problem, where the source of the problem is, and most importantly, if it is a problem for your equipment or not. A maintenance person in one part of the world can review the system’s performance as the local electrician and the electric utility representative review the information. Comparisons against baseline studies, susceptibility charts, PQ indices, and many other tools available in the monitors and/or software programs from the leading PQ instrument vendors help you quickly get production efficiently running again.
To continue to increase productivity (and profitability), more nines need to be added to the reliability figures by preventing problems from recurring in the future. And the power quality tools are available for just that; you just need to look in the crystal ball.
BINGHAM, manager of products and technology for Dranetz-BMI in Edison, N.J., can be reached at (732) 287-3680.