Harmonics? Power Quality Disturbances?
The US standard electrical grid runs at a frequency 60Hz. So, what does this mean? To clarify, 60Hz means that the flow of current changes direction 60 times per second.
A harmonic(s) is defined as the content of the signal whose frequency is an integer multiple of the 60hz systems.
Power quality disturbances, however, are harmonics changes in the voltage shape, and the waveform increases the current and power factor supply levels.
When harmonics are not the frequency of 60Hz, we call this a harmonic distortion. These odd multiples of the number three (3rd, 9th, 15th, and so on) are particularly troublesome since they behave like zero-sequence currents, which is an unbalanced current. These triple harmonics are additive due to their zero-sequence-like behavior.
The harmonics that usually cause the most impacts on a facility’s power system are (3rd, 5th, 7th, and 9th). The presence of harmonic distortions can impact equipment in a facility. As well as, increase the cost of usage and shorten the life of the equipment.
Defining Harmonic Distortion
Placing power quality metering upon the electrical system is a must when determining what is occurring with an electrical system. This process allows one to measure the main point of entry and throughout electrical distribution equipment.
Installation can be permanent with an electrical power monitoring system (EPMS) or temporary with power quality recording meters. Moreover, installed metering offers the capacity to be uploaded into software capable of measuring each frequency cycle and identify all harmonic distortions present in the electrical system.
A Harmonic Solution
Having the correct power quality metering installed allows businesses to identify the suspect frequency distortions and define the harmonic source. As a result, it provides the solution to mitigate the issue. Maintaining the ability to see what occurs with the frequency of the 60 Hz electrical system in a facility remains a small investment compared to the cost of manufacturing and equipment failure.
Brian Curnutt, APT Field Service Manager