Power Quality problems are increasingly caused by in-house equipment; yet a misconception still exists that when an electrical disturbance does occur, it originates from an outside source.
As the business community has grown increasingly dependent upon computers and other complex electronic equipment, the need for reliable power has become critical. Corporations and institutions alike are annually losing billions of dollars from lost manhours due to computer downtime.
Types of Problems
There are various types of electrical disturbances.
Impulses and Spikes are fast fluctuations in voltage caused by lightning, switching capacitors, power supplies, or rectifiers.
Sags, Swells, and Surges are all voltage variations that are short in duration and are caused by a motor starting, welders, etc.
Longer voltage variations come in the form of Overvoltages and Undervoltages. These can result from circuit overloads, utility reductions, and poor voltage regulation.
Electrical Noise and Harmonic Distortion can result from a variety of electronic equipment including computers, motor drives, UPS, rectifiers, inverters, welders, and electric furnace controllers.
Finally, an Outage results from transformer failures, generator failures, downed power lines, or power system faults.
Identification of Problems
There are a variety of symptoms resulting from power quality problems: undervoltage trips; transformers and/or motors overheat; neutral conductors overload; circuit breakers trip for no apparent reason; starters trip sporadically; utility rate penalties for low power factor; emergency generator start & run problems; telecommunication distortions; and many other symptoms.
There is no catchall solution. Because there are so many potential causes of these problems, there are just as many potential solutions.