UPS Auxiliary supply to Intelligent MCC 1

[heraklio]

Dear all,

I am involved in the electrical engineering design of a industrial plant for which Intelligent type MCCs are required. My intention is the auxiliary supply to this MCC to be from UPS.
OK, on the other hand I need UPS power for Automation equipment and Instrumentation.
The UPS system shall be redundant as per specs.
The question is: should I install two UPS systems, one for MCC control and another one for ICA loads or could I install a common UPS for all the loads? What is your experience regarding this?

And as a step further, the auxiliary DC load for MV switchgear, should it be taken from independant batteries or could I use the same batteries as for the UPS?

Thanks in advance.

 

[dpc]

I would not combine the station batteries for the MV switchgear with the UPS. That would increase the risk of discharging the batteries should the charger fail.

As for the MCC aux power, if there is a lot of analog instrumentation that might be sensitive to voltage transients or EMI on the supply voltage, I'd keep the instrumentation power separate.

You might also look into operating the MCC starters on 24 V dc, instead of from a UPS.