Harmonic current in one leg of 3-Phase supply

[PhaseShift]

In our facility I noticed that one of the 4.16kV feeder circuit feeding a 4.16kV-480V Delta/wye transformer was showing about 20% Total Harmonic Distortion (THD) on the B phase while the other two phases read only about 3% or so. There are no single phase L-N loads connected on the secondary 480V side of the transformer.

What can cause the harmonic distortion to be high in only one of the phases such as this?

 

[mivey]

In our facility I noticed that one of the 4.16kV feeder circuit feeding a 4.16kV-480V Delta/wye transformer was showing about 20% Total Harmonic Distortion (THD) on the B phase while the other two phases read only about 3% or so. There are no single phase L-N loads connected on the secondary 480V side of the transformer.

What can cause the harmonic distortion to be high in only one of the phases such as this?

What was the amps? High THD with low current doesn't mean a whole lot. Better to look at the THD on the voltage instead.