Who cares or should care about harmonics?

Who cares, or who should care, about harmonics?

From a designer or a consultant standpoint, if you’re designing a building or a facility, such as a water treatment plant, for a customer—you need to care about harmonics. If you’re adding multiple variable frequency drives (VFDs) and rectifiers because you want the system to be robust, these loads are going to create harmonics and push them back onto the system. You don’t want your customer to come back to you in 10 years and say they have a problem related to harmonics because you made bad design choices. 

Plant operators and people who are operating the facility care about harmonics because if their system fails or doesn’t work properly, it’s on them to worry about and fix the problem. 

End users, whether on a residential, plant or larger facility level, also care about harmonics. There could be harmonics issues in the home or flowing from LED lights. Harmonics on a small scale or a large scale—doesn’t matter—they can be a problem. 

Salespeople also need to be aware of harmonics. For example, if you are selling VFDs to a customer and want them to have the best quality system, you may need to know IEEE 519 compliance and how to reduce harmonic currents to a very low level. It is your job as the salesperson to instruct or help guide the customer to reach the right level of distortion. But on the flipside, if you oversell a bunch of harmonic solutions that the customer doesn’t need, then you’ve cost the customer more money and that is a problem. The salesperson needs to sell the right amount of equipment at the right level, depending on the size of the system and the amount of harmonic current that’s going to be generated by those loads. 

Finally, the utility cares about harmonics because it is the mediator. If a facility is producing harmonics and distorting another facility’s voltage, there are going to be problems. This is where the point of common coupling comes into play and allows the utility to mediate and guide the customers to make sure that one facility is not negatively affecting another in terms of the electrical system.  

So, who cares about harmonics? All of these different people do, whether a designer, an operator, an end user, a salesperson or a utility. Everyone needs to have an understanding of harmonics. A lot of current distortion doesn’t necessarily mean there’s going to be issues. Different factors need to be considered. We all need to do the right thing from a cost perspective and design perspective.