Hello,

using the tool Sizer, you can calculate the harmonic distortions of these devices as the distortions are depending on your grid impedance.

SIZER is a useful tool for Harmonic predictions.

Also consider how supply harmonic distortion is created. 

The inverter drive is a non linear load, as the DC Link rectifier commutates the resulting current distortion is supplied by the supply; which at some point is provided by the supply transformer. The impedance of this supply therefore has a major impact upon the resulting Voltage distortion.

It is therefore the combination of the drive load and the impedance which creates the harmonic distortion, not the drive in isolation.

Supply, fault level, Voltage, impedance, and capacity are required by the tool for assessment.

For low cost attenuation consider 2% or 4% input reactors, thereafter harmonic filters and even costly active harmonic filters, to bring the distortion within acceptable limits.

A harmonic analysis of the installation prior to the addition of these inverter drives is essential, as existing distortion may be present in the system. If this is a modification to an existing installation, then any work you carry out may incur costs for correcting for the whole system.

It is common for 'specifications' to request the Harmonic distortion created by individual inverter drives, failing to accept that, it is the while supply system back to the 11kV side of the supply transformer which has to be taken into consideration. Further if the supply transformer is inadequate for this type of load, the cost of accommodating for this situation can be very high.

In summary:

Cost in, a pre installation Harmonic survey, by a competent organisation.

Obtain supply system detail, Capacity, fault level, impedance.

Use the SIZER assessment tool.

Be 'risk adverse'.

N.b, 3rd harmonic (Triplen) is produced by single phase loads, and not created by 6 pulse inverter drive systems. The drives you are considering are 6 pulse devices creating 5th, 7th, 11th etc.

Tractor