Harmonics - the Hidden Enemy

Harmonics are usually cause problem for sensitive equipment. The power losses from harmonics is usually small compared with other process losses such a keeping the plant door open in the winter or running both AC and heating all year long because nobody can adjust the HVAC system properly.

I don't believe that energy savings will ever be a "real" advantage for a filtering equipment especially that those same equipment do have their own losses...

Buyer beware...

So you are saying that if you do not have sensitive equipment, there is no reason to add filtering to eliminate the small amount of harmonics created by the drives. I have 87 AC drives running 24/7/365. I am working with NYSERDA now to qualify for some rebates as this is an all new plant with last system to go on line in the next 2 weeks.

NYSERDA is requiring these to be at least 3% impedance, they are only 2% from the factory. I am waiting to see if they are requiring me to add Line reactors to each drive to meet the 3%. Then I have to weight the cost + labor+ additional materials vs rebate from NYSERDA. I am not worried about harmonics due to 0 sensitive equipment in the plant other than the drives. I don't know how efficient these drives are VS ACL, Aside from the 0 inrush and operating average @ 48Hz. our electric bill is $35,000.00+ / Month.

Jim,

I wrote: "I don't believe that energy savings will ever be a "real" advantage for a filtering equipment especially that those same equipment do have their own losses..."

We were talking about power losses, not pollution... Now, you still have to meet the utility requirements so that you don't damage the neighbor's equipments. IEEE 519 still applies to NA plants.

Any plant has sensitive equipments. Your telephone system is one of them. Your main transformer might overheat if it feeds mostly VFD. 3% line inductors is a good rule of thumb to reduce the harmonics current drawn by VFD to about 20% ITHD. It might not be enough to meet IEEE if your electrical load is mostly drives. We usually assume that there is a sizable part of the plant load that is linear but it is not always the case.

You wrote : "Aside from the 0 inrush and operating average @ 48Hz. "

Is there a typo in this line? I don't understand what you are trying to say.