When do you need a Power Quality expert?
When should you contact a Power Quality expert? There are many cases where calling a power quality expert isn't necessary right away. Electricians do a fantastic job with diagnosing issues and problems that often occur in facilities. Often times a failed breaker, loose connection or overloaded circuit can cause issues within a customer's facility. While these issues can sometimes be clear to diagnose, there are many times were a complex issue cannot be solved by basic intuition. A full power quality audit records and graphs all the power quality figures of merit. These include Voltage, Current, Harmonics, Power Factor, Transients, sag/swell detection, waveform snapshot during power events and finally a trend of the power at the location. These parameters give the power quality engineers a clear picture of what is going on and provides the basis for our recommendations alongside ANSI and IEEE power quality standards.
Over the years many customers have attempted to resolve issues with equipment utilizing their electrical contractor. Many equipment malfunctions can be resolved by the keen eye of an experienced electrician. However there are many situations where reoccurring problems cannot be resolved regardless of the countless hours the electrician has spent on replacing motors, wiring or even expensive control systems. A power quality issue that is caused due to system phenomena cannot be corrected with new wiring or a new breaker. After the electrician has exhausted his efforts, a call to a power quality expert is often times the escalated path they must utilize to solve their problems.
A power quality investigation will be able to test and characterize the power system in the facility. A report of the important power figure of merits of the electrical system is produced after the power quality study. The power quality data often times shows the source of the issue if an electrical issue is the root cause.
A great example of this is a customer who had their electrician replace a failed three phase motor about once a year over a five year period! The electricians checked the voltages and current balance at the motor and everything was within specification. The motor was previously de-rated appropriately for the current unbalance on the incoming line. Upon a power quality investigation it was found that the voltage total harmonic distortion at the motor was well above 9% (predominantly the 5th harmonic). The high harmonics caused excessive motor heating and significantly reduced the lifetime of the motor. The total harmonic distortion was a manifestation of non-linear loads in that section of the facility. A power quality report was presented that recommended selective harmonic filtering be installed on that electrical panel. The fifth harmonic was eliminated by a harmonic scrubber that was designed based off the data outlined by the power quality report. The customer has since then enjoyed 3 years and counting of trouble free three phase motor operation.
This is one of many examples where the customer had exhausted their efforts to solve a recurring issue using the standard electrician route. A power quality study can be a tremendous asset to facilities that have electrical issues which cannot be resolved using standard electrical testing.