Excessive Load in UPS due to Harmonics

[dannyboy]

I have been told by a Contractor that they are seeing 30 amps of additional load on the UPS because of "dirty" power. Especially the 13th Harmonic. The claim is that to maintain the Load side having about 35 amps, the UPS is working overtime to convert the power on the line side.

This makes no sense to me.

Am I missing something?

Is there a suggested fix.

We have overhead, going down in the ground for about a 100 feet to a 12.47 KV - 208/120V delta Y, pad mounted transformer. This feeds an 800A ATS and gear. This gear feeds the 30 KVA UPS. The claim is the generator does not create a problem.

 

[GoldDigger]

Is this a constant on, dual conversion UPS?
What is the voltage percentage of the 13th harmonic?
Would that be one of the main current harmonics from a twelve pulse rectifier load somewhere?

 

[dannyboy]

This is one building within a amunition (bullets) plant. I do not have any data on what is causing the issue. The plant randomly runs equipment and much of it is original from the 1940s. Attached is the standard DoD specification used for bid. The UPS loads are computers, radios, etc typical for and emegency dispatch room and Telecommunications Equipment Room.