The “Profile of the Electrical Contractor” in the July issue of ELECTRICAL CONTRACTOR showed 65–70 percent of those surveyed indicated they performed power quality work. Companies with 10 or more employees are more likely than smaller firms to perform power quality work, which may be due in part to the cost of some of the power quality tools. More than twice as many electrical contractors who undertook power quality training last year planned on doing so this year. And in training methods in general, the majority favored hands-on training, with only a small percent of people picking self-paced videos/CDs or webinars as their favorite method. The get-your-hands-dirty method seems to work best.
The ideal training session, from the trainer’s perspective, is a mix of classroom and hands-on exercises. While one could probably construct an elaborate setup to explain and demonstrate the basic principles needed when monitoring and analyzing for power quality problems or when conducting a benchmark study, a whiteboard and an LCD projector is more effective in explaining these concepts initially. Covering concepts, such as Ohm’s and Kirchoff’s Laws, intermixed with case studies that demonstrate how to apply them, is the way to go. Then it can be followed up with hands-on measurements using the “weapons-of-choice.” Seeing what can and what cannot be measured and recorded by power quality meters and monitors is a good education.
Use of both a power quality waveform generator and the actual powerline connections is valuable, as just about every location nowadays has some power quality phenomena that can be observed in the waveforms. While having a meeting with a customer in their home office, I plugged a power quality monitor into a 120-volt (V) receptacle in preparation for a hands-on demo. Unexpectedly, the monitor beeped periodically, indicating that a power quality disturbance had triggered the monitor, and it recorded the waveforms, such as the one in the figure below. If this 300V peak-to-peak, bipolar transient had occurred on a point on the wave closer to the peaks of the sine wave, there could have been significant damage to equipment that wasn’t protected by adequate transient-voltage surge suppression (TVSS).
There are plenty of places from which to get such power quality training for all skill levels, including institutions and colleges. The National Joint Apprenticeship and Training Committee recently developed a course based on a new book on power quality analysis that was written with the electrical contractor in mind—not as an engineering textbook. Also, regional and national conferences offer courses on power quality.
Some power quality trainers host free seminar courses, but the level of detail and hands-on experience are fairly limited in such. The more extensive courses can run from $250 to several thousand dollars, depending on number of days, location and class size. A typical course outline might be similar to the following:
• Understanding and applying Ohm’s and Kirchoff’s Laws
• Determining the quality of the facility wiring and its impact on power quality and equipment interaction
• Identifying the types of power quality phenomena and their cause and effect
• Making the proper connections for the wiring configuration and instrument
• Analyzing recorded power monitor- data and determining what is important
• Evaluating the quality of utility electrical service and what is normal
• Identifying the impact of facility/utility interface configuration
• Judging the effects of multiwire distribution and load harmonics
• Evaluating and selecting effective power mitigation devices
• Assessing the effect of various loads on a facility
• Measuring the interference loop created between electrical wiring and network wiring
• Planning and performing an effective power quality survey
• Preparing a survey report and presenting the data in a meaningful and effective manner
There also are more specific courses, tailored for the National Electrical Code, stray voltage, telecommunications, data centers and more. At any level of experience, there are training and educational courses that can increase knowledge and your revenue stream with only a minor investment.
BINGHAM, a contributing editor for power quality, can be reached at 732.287.3680.