Rcd Nuissance Tripping Caused By Vsd

[munkey]

Hi,

 

Can anyone shed any light on this as it baffles me!

 

When feeding a machine which contains 5 VSD's (up to 260Kw) with a power supply, the French construction industry requires that supply to be fed from a 30mA RCD.

 

This always causes a problem, which i think is down to the harmonics on the supply caused by operating the VSD's.

 

The VSD's are all ABB and so contain Filters to help with the 'noise' on the supply but obviously just not enough.

 

At the moment the only solution is to use expensive and bulky isolating transformers on the incoming supply, but this obviously means that after the Tx the equipment is not RCD protected.

 

Has anyone had similar problems?

 

Can anyone give any cheaper/smaller solutions that will allow use with a 30mA RCD.

 

Many thanks in advance

 

Munkey